Lifestyle Chemistry · SAIRAH MURRAY – SENIOR SCIENCE NOTES 3 1.1.3 Explain that mixture can be:...

SAIRAHMURRAY–SENIORSCIENCENOTES 1

Lifestyle Chemistry

2 SAIRAHMURRAY–SENIORSCIENCENOTES

1.1.1 Identify that a wide range of substances are used daily as part of our food, our hygiene, and maintenance of our health

• Conditioner • Soft Drink • Detergent • Face Cream • Foundation • Toothpaste • Orange Juice • Sunscreen • Mayonnaise • Milk

1.1.2 Identify that solutions, colloids and suspensions occur in a wide

range of consumer products

Item Solution/Suspension/Colloid Advantage Conditioner Colloid It is smooth, adds a layer of

protection and hydration to the hair strands

Soft Drink Solution It allows for a smooth consistency and for a

sweet taste (sugar + water = solution)

Detergent Solution

The detergent holds to dirt and holds it within the

molecules Face Cream Colloid You want the product to

distribute evenly over the face

Foundation Colloid You want the product to distribute evenly over the

face Toothpaste Colloid Evenly distributes the

product throughout the mouth and provides and

even texture Orange Juice Suspension The pulp makes the orange

juice a suspension. You have to shake it to give it

flavour Sunscreen Colloid You want the product to

distribute evenly over the face and body so that you

get protected Mayonnaise Colloid Allows for even texture

Milk Colloid Evenly distributes all the fat and smooth consistency


1.1.3 Explain that mixture can be: - solutions that contain dissolved substances and are uniform

throughout - suspensions containing particles that settle out, or form

layers, quickly - colloids with particles that remain suspended for long periods

of time and include: • liquid-in-liquid (emulsions)

o oil-in-water o water-in-oil

• gas-in-liquid (foams) Many consumer products are mixtures of chemicals and appear in the form of solutions, suspensions and colloids. Products containing these types of mixtures may have emulsifiers added to them. Solutions are mixtures that contain at least one dissolved substances and are uniform throughout. The dissolved substance is known as the solute, and the solvent is the substance it is dissolved in. Examples include saltwater, household ammonia (a solution of ammonia gas in water) and vinegar (a solution of acetic acid in water).

Colloids are cloudy mixtures with particles that remain suspended for long periods of time. In a colloid, the particle of one substance are scattered throughout another. Colloids include oil-in-water mixtures, water-in-oil mixtures, gas-in-liquid mixtures (foams such as whipped cream which is a mixture of air in cream) and liquid-liquid (which is an example of oil-in-water). The advantage of a colloid is that, unlike a suspension, the particles will not settle out In a colloid, the particles are larger than in a solution but smaller than in a suspension. In colloids, the particles do

not settle out. The particles are too small to remove by filtering. When a beam of light is shone through a colloid, some of the light is scattered. This produces a bright cloudy effect.

• A gas dispersed in a liquid forms a foam – shaving lather • A solid dispersed in a liquid forms a solid form – Styrofoam • A liquid dispersed in a gas forms an aerosol – hairspray • A liquid dispersed in another liquid form an emulsion, when an emulsifier

is present – homogenised milk • A liquid dispersed in a solid forms a gel – jellies • A solid dispersed in a gas forms a solid aerosol – dust or smoke in the

air • A solid dispersed in a liquid form a sol – ink


Oil in Water Emulsions • Most common emulsion used around the home. • Examples include:

• Face cleanser • Hand lotions • Conditioner • Paint • Lipstick • Floor wax • Milk

Water in oil emulsions

• The types of surfactant molecules present in water-in-oil based emulsions are long starch molecules or protein chains.

• The chains wind among minute water droplets and prevent them form merging.

• Properties: • Poor conductors of electricity • Poor conductors of heat • Feel warm • Greasy and sticky to touch • Water evaporates slowly • Direct contact between the surface

and the oil phase, sunscreen • Are not miscible with water

Suspensions are mixtures containing large particles that settle our or form layers quickly. In a suspension the particles are larger than those in a colloid and can be removed by filtering. The advantage of a suspension is that particles eventually settle out and can be separated from the liquid.

• Beaten or whisked eggs • Salad dressing – oil and vinegar • Mayonnaise


1.1.4 Explain surface tension in terms of the forces experienced by particles at the surface of a liquid

Refers to the forces experienced by particles at the surface of a liquid. In any liquid, there are forces of attraction between molecules. These forces of attraction act equally in all directions on the molecules of the liquid. Molecules in the surface layer are very strongly attracted by the molecules in the layer underneath, but not by the molecules in the air above. The forces between the particles at the surface of a liquid make the liquid behave as if a stretched invisible skin covered it.

• The shape of liquid drops • The formation of menisci • The ability of some insects to walk on water. This is similar to

floating a needle on surface tension of the water prevents it from sinking.

Surfactant chemicals is the name often given to detergents. Surfactants are the main ingredients in cleaning products. Surfactants are a group of chemical substances that are surface-active-agents. Surfactants affect the surface tension of a liquid, such as water, thereby making water “wetter”. It is this property that makes surfactants useful as cleaning agents. In the presence of a surfactant, water has a greater ability to wet the dirty or oily surface and the dirt or oil can be more easily removed. Surfactants are used in a range of consumer products including satin and dirt removers, spray on oven cleaners, shampoos and anti-static and sanitising agents used in friction reducers such as hair rinses and fabric softeners.

• Catonic detergents, such as those found in disinfectants and fabric and hair conditioners, which ionise in solution to form a positive charge

• Non-ionic surfactants are low sudsing, and are usually used in laundry and automatic dishwashing detergents and rinse aids. They do not ionise in solution and therefore don’t carry an electric charge.

• Amphoteric surfactants are used in personal cleansing and household cleaning products because their mildness, sudsing abilities and stability.


1.1.5 Describe surfactants as substances that affect the surface tension of a liquid

Oily substances and water are example of substances that do not mix well. When put together they normally form a liquid-in-liquid colloid or suspension. Emulsifiers are substances which are partly water-soluble and partly oil soluble. Emulsifiers bring oil and water together. Soaps and detergents are emulsifying agents and surfactants, that is, soaps and detergents emulsify oils and greases and change the surface tension of liquids. Emulsifying agents reduce the difference in surface tension between two substances. This enables the substances to mix together. Soap is an emulsifying agent or emulsifier. Soap causes grease to be taken up by water as an emulsion and washed away. The dirt is washed away with the emulsified grease.

An emulsion is a mixture that contains two substances that do not normally mix well. To from an emulsion, an emulsifying agent must be added. The two liquids that do not ordinarily mix are called phases. To make the two phases mix together, an emulsifier must be added to reduce the difference in surface tension. The particles in the emulsion must also be small; if they are too heavy, they will settle into layers. Many cosmetics, foods, lubricants, medicines and paints are examples of emulsions. Milk is an example of a emulsion; butterfat (oil) in water to mix together is a protein called casein. In many emulsions, the liquids will separate after a certain time. The finer the particle size, the more stable and the more viscous the emulsion is. Water evaporates from oil-in-water emulsions leaving a film of the oily substance behind. If you apply a water-in-oil emulsion to your skin, you would feel a cooling effect. Water-in-oil emulsions are also useful because they allow direct contact between the surface and the oil phase.

• Oil-in-water emulsions: oil molecules are dispersed in water. Water

evaporates more readily from this emulsion. This emulsion can be dyed by water-soluble dyes, such as food colouring.

• Water-in-oil emulsions: water molecules are dispersed in oil, therefore the water evaporates less quickly. This emulsion can be dyed with oil-soluble dyes, such as fuchsin. Oil has a higher electrical resistance than water. For this reason, a water-in-oil emulsion is a relatively poor electrical conductor.


1.2.1 Process and analyse information to identify the range of chemicals used in everyday living including:

- Detergent - Lubricant - Pesticide - Solvent - Metal cleaner - Body hygiene chemicals - Cosmetic

And outline any precautions that may be needed in the use and handling of these chemicals

• Detergents (Wonder Soaker) contains ingredients which remove dirt from clothes (anionic surfactants), soften water and disperse oils (sodium polyphosphate), remove bleachable stains (sodium perborate), break up greasy dirt (sodium carbonate, sodium silicate), break down protein stains (enzyme), improve product processing (sodium sulfate) and small quantities of brightener and perfume.

• Lubricants – lubricating oils such as those used in car engines are made up of hydrocarbons (made from oil) with additives such as rust inhibitors, anti-wear agents and dispersants. Dispersants are usually heavy metal soaps (surfactants)

• Pesticides – in Australia pesticides contain organophosphates. They use many varieties of complex chemicals and may be classified by the type of animal killed, the way they act or the chemical group to which they belong. Many pesticides are accumulates in the food chain and thus cause environmental concern.

• Solvents – are liquids in which we can dissolve another substance, which is then called the solute. Ionic substances (where a positive ion bonded with a negative ion) and polar substances dissolve in polar solvents like water and alcohol. Non-polar substances dissolve in non-polar solvents such as turpentine, petrol, carbon tetrachloride and hexane. Methylated spirits (mainly ethanol) and strong solvents such as paint thinners (liquefied hydrocarbon) and mineral turpentine are highly flammable and can damage skin. substances dissolve in polar solvents like water and alcohol. Non-polar substances dissolve in non-polar solvents such as

• Degreasers dissolve oils, fats and greases, which are no soluble in water. Water is a polar substance and will only dissolve other polar substances. Non-polar substances, such as oils, will dissolve only in non-polar solvents such as hexane. Degreasers contain non-polar solvents and are used to clean oil and grease off machinery.

• Metal cleaners – such as Silvo contain abrasive particles (the polish) in methylated spirits. They are used to remove tarnish from metals. It results from the reaction of the metal with the oxygen in air. This type of chemical reaction is called corrosion. Metal cleaners also contain detergents and corrosion inhibitors to slow further tarnishing.

• Body hygiene chemicals – such as deodorants often contain aluminium compounds. These products are often solutions or suspensions but colloid mixtures are most common.


• Cosmetics – are made from oil and water with an emulsifying agent. These products are often solutions or suspensions but colloid mixtures are most common.

1.2.2 Use first-hand or secondary sources to gather, process, analyse and present information to identify examples of suspensions and colloids and outline one advantage of a mixture being in each form

Colloids are classified according to whether a solid, liquid or gas is dispersed and the medium of the dispersion.

• A gas dispersed in a liquid forms a foam – for example, shaving cream

• A solid dispersed in a liquid forms a solid foam – for example, Styrofoam

• A liquid dispersed in a gas forms and aerosol – for example, hairspray

• A liquid dispersed in another liquid forms and emulsion, when an emulsifier is present – for example, homogenised milk

• A liquid dispersed in a sold forms a gel – for example, jellies • A solid dispersed in a gas forms a solid aerosol – for example,

dust or smoke in air • A solid dispersed in a liquid forms a sol – for example, ink

The advantage of a suspension is that particles eventually settle out and can be separated from the liquid. The advantage of a colloid is that, unlike a suspension, the particles will not settle out.

1.2.3 Plan, select appropriate equipment or resources for and perform a first-hand investigation to produce a range of suspensions and colloids that are used by consumers including: - Beaten or whisked eggs - Salad dressing (oil/vinegar) - Mayonnaise

Part A : Foam Materials: • 2 egg whites at room temperature • ¼ tsp. cream of tartar • 2 mixing bowls of the same size • Electric mixer • 2 x 250ml beaker • Measuring spoons


Procedure: 1. Beat one egg white with an electric beater mixer until stiff peaks

are formed. 2. Pour the beaten egg into a beaker 3. Beat a second egg white and add 1/8 tsp of cream of tartar. Beat

again until stiff peaks form. 4. Pour into a beaker 5. Let the two mixtures stand

Part B : Suspension and Emulsion Materials: • 2 mixing bowls • 2 wire whisks • 250ml beaker • Measuring spoons • 1 egg yolk • 30ml vinegar • 500ml vegetable oil (2 x 250mL) • Measuring cylinder

Procedure: No emulsifier

1. Add 15 mL vinegar to a mixing bowl 2. Add oil, 15 mL at a time while continuously beating the mixture until

80mL has been added 3. Add 15mL of vinegar and continue to beat mixture 4. Repeat steps 2 and 3 until all liquids have been added

Emulsifier 1. Add egg yolk and 15 mL of vinegar to a mixing bowl 2. Beat vigorously until slightly thick 3. Add oil, 15mL at a time, while continuously beating the mixture,

until 80mL has been added 4. Add 15 mL of vinegar and continue beating the mixture 5. Repeat steps 2 and 3 until all liquids have been added

Note: the emulsion will not form unless the oil is added VERY slowly. You will know you have formed an emulsion when the mixture turns white and thick. Egg contains lecithin, which is an emulsifier Discussion The advantages of suspensions and colloids Mayonnaise could be made as a suspension in which the oil floats on top of the water. This mixture would need to be shaken when used. Such a product does not look inviting to use and the oil droplets formed by shaking would be much bigger than in a colloid. The advantage of the mayonnaise emulsion is that it looks better than oil floating on the top of the water and probably tastes better.


Homogenised milk has been processed so that the milk fat is reduced is size and spread evenly throughout the milk, this produces a “richer” taste and even texture. Un -homogenised milk has large fat globules which will rise to the top of the milk and produce a layer of cream. Many people do not like this texture. Skin creams can also be colloids or suspensions. A thin layer (oil) can easily spread over the skin. The water carries with it oil that is important to condition the outer layer of the skin. Chemicals that are insoluble in water can easily be carried into the skin. The chemicals are dissolved in the oil phase. Calamine lotion is a suspension as it allows for a solid (power) to be evenly distributed on to the skin.

1.2.4 Perform first-hand investigations to demonstrate the effect of surface tension on: - The shape of liquid drops - The formation of menisci - The ability of some insects to walk on water

The shape of liquid drops

The formation of menisci

The ability of some insects to walk in water. The surface tension of the water prevents the insect from sinking.


1.2.5 Process and present diagrammatic information to describe the effects of soaps, skin cleansers and shampoos on the solubility of oil

2.1.1 State the relationship between the properties of an emulsion and

the types of molecules present The properties of an emulsion depend on the type of particles present. Oil-in-water emulsions have different properties to water-in-oil emulsions. Two common types of emulsions are: • Oil-in-water emulsions à In this emulsion the tiny oil droplets are

spread throughout a continuous water phase. • Water-in-oil emulsions à In this emulsion tiny droplets of water are

spread throughout a continuous oil phase.

Each type of emulsion has distinct properties. Possible properties include: • The emulsion can feel cool or feel greasy • Water will mix easily with the emulsion [depending on the

concentration of the water the emulsion can become a free flowing or creamy liquid.

• Water will not mix easily with the emulsion [these type of emulsions tend to be thicker pastes]

• The emulsion can be a poor or good conductor of electricity. • Certain dyes will only dissolve in, and therefore stain, the dispersed

phase of the emulsion (water-soluble dyes – Methyl orange; Oil-soluble dyes – Sudan III)


2.1.2 Outline the purpose of the emulsifying agent in a range of consumer cleaning products

An emulsifying agent is a surfactant. That is, it is a “surface active agent”. Surfactants work at the boundary (the interface) between two substances. A surfactant molecule has two chemical groups: one end that is attracted to water (hydrophilic) and the one that is attracted to substances that are not water-soluble (hydrophobic). As an emulsifying agent the hydrophilic end of the molecule projects into the water. The hydrophobic end of the molecule projects into oil. When the mixture is shaken oil droplets form, and the surfactant molecules surround each of the dispersed droplets The molecules prevent the droplets from joining and so maintain the stability of the emulsion. The suspension has now been “emulsified” – an even spread of oil droplets in water that is relatively stable.

2.1.3 Identify that soaps and detergents are emulsifying agents and

surfactants Soaps and detergents are emulsifying agents and surfactants, that is, soaps and detergents emulsify oils and greases and change the surface tension of liquids. Soap is an emulsifying agent as it causes grease to be taken up by water as an emulsion and washed away.

2.1.4 Explain why cleaning agents must be surfactants and emulsifiers

The purpose of the surfactants in cleaning products is to break up greasy oil based compounds into small droplets. Then the emulsifying agent helps to thoroughly disperse the droplets and then keep the droplets separated.

2.1.5 Define the term biodegradable

The term biodegradable is applied to those substances that can be decomposed by fungi and microorganisms such as bacteria. Soaps are generally more biodegradable than detergents. Biodegradable products are less harmful to the environment than non-biodegradable ones because they do not accumulate in the environment. Soap biodegrades very rapidly and it tales only a few days for the microorganisms to do their work.

2.1.6 Discuss the biodegradability of soaps and soapless detergents

Chemicals in hard water react with soap to form scum. When it was found that soaps were not effective in hard water, synthetic detergents were manufactured. Detergents are like soaps but do not create scum. The first detergents were branched-chain alkyl benzene sulfonates, which do not biodegrade in sewage treatment plants. The bacteria used in sewage treatment plants digest unbranched linear chain molecules, such as those in soap. This is why soap is biodegraded more easily than detergents. Additives in synthetic detergents pose additional problems. For example, phosphates, which are added to remove soluble calcium salts in hard water, cause problems in water systems. Most detergents contain wetting agents that assist transport of pollutants deeper into soils.


More recently, biodegradable, phosphate-free detergents have been developed. Soap molecules are not very versatile and cannot be adapted to today’s range of fibres, washing temperature and water conditions. The effectiveness of soap is reduced in hard water – water which contains a high level of calcium and magnesium salts. Soap scum does not wash away easily and tends to leave visible deposits on clothes, and attaches to the insides of baths, sinks and washing machines. Detergents are more versatile cleaning products because they can be adapted to perform well under a variety of conditions, are less affected by water hardness (therefore lathering more easily) and don’t from scums. In the 1960’s, enzymes were added to detergents to break down blood and other protein stains, and solvent-based pre-wash removers developed.

2.2.1 Perform a first-hand investigations to prepare an emulsion and

compare its properties to those of a solution and suspension Colloids can be distinguished from solutions by:

a) Their inability to diffuse through a semi-permeable membrane, and

b) Their ability to scatter light, that is, an emulsion will scatter some light to produce a cloudy effect, whole the solution will allow light to pass through with no scattering

To make a paint emulsion:

1. Mix together distilled water and pigment 2. Grind the mixture, The mixture of pigment and water is a

suspension. Observe its properties. 3. Add egg yolk (containing the emulsifying agent) to from and

emulsion. Observe its properties.

2.2.2 Plan, chose equipment or resources for, and perform a first-hand investigation to gather information about the properties of different emulsions and use available evidence to compare those properties • Moisturising creams, lotions and milks, vanishing creams and

foundation creams are oil-in-water emulsions • Paints contain a pigment, a binder to hold the pigment in place and

a solvent such as water (water based paints) or turpentine (oil based paints)

• Hair gel is an emulsion of fat in oil • Peanut butter is an emulsion of peanuts, sugar, salt and vegetable

oil. Peanut butter may also contain an emulsifying agent that prevents the oil separating out.


3.1.1 Identify the role of the skin as: - An organ to separate the body from the external environment - An organ assisting in body temperature control - An organ to protect against entry by disease-causing

organisms Skin forms an airtight; fairly waterproof covering that protects the body from changes in the external environment. The skin helps to conserve water. Skin pigments shield the rest of the body from the harmful effects of excessive light. The skin is a mechanical barrier. The outer layer of the epidermis protects he body from minor mechanical injuries.

Skin assists in body temperature control. Humans have warm and cold receptors present in the skin. In response to increased temperature, small blood vessels in the skin dilate, increasing the blood flow to the skin and therefore the amount of heat lost by radiation. The activity of the sweat glands also increases. In response to cold, blood circulation through the skin decreases, the activity of the sweat glans decreases, and hairs on the skin become erect to trap an insulating layer of air (seen as goose bumps in humans). Skin protects against disease-causing organisms. The outer layer of the epidermis forms a barrier against bacterial invasion. Unbroken skin protects other tissues and collects and holds pathogens (disease-causing organisms). Acid pH of the skin discourages growth of many microbes. Oil glands on the skin secrete fatty acids that inhibit the growth of some bacteria and fungi.

3.1.2 Define the term ‘microflora’ and discuss the role of the microflora

on skin in different parts of the body The term microflora includes bacteria, fungi, algae, protozoa and viruses. Hundreds of bacteria live on the skin, in saliva and in the large intestine. Most of these are harmless, and sometimes are even beneficial. Some of the bacteria and fungi can be beneficial. Some can be harmful (such as fungus that causes tinea). Bacteria such as lactobacilli are natural microflora found in the gastrointestinal tract. These microflora can help combat pathogenic (disease-causing) microorganisms. Drier parts of the body such as the scalp support fewer micro-organisms but moist areas such as the armpit support a larger population. Some microflora thrive in these harsh conditions, using the nutrients in sweat and sebum for their needs. An imbalance if microflora in the body or on the skin can cause conditions such as tinea and thrush. Thrush is a disease caused by an imbalance in the growth of the fungus ‘Candida albicans.C.albicans’ is one of the natural microorganisms of the human body that occurs in the mouth, respiratory tract, female genital tract and gastrointestinal tract.


An increase in microflora can be brought about by antibiotics or steroids, the use of oral contraception (the pill), pregnancy, malnutrition and diabetes mellitus. When the bacteria come into contact with the epidermis, they cause red spots. White blood cells then congregate to attack the bacteria, form pus, which in turn forms the pustules we call pimples. The skin is generally an inhospitable place for the most microorganisms; some microbes are established as part of the normal flora. Some aerobic bacteria produce fatty acids from sebum. These acids inhibit the growth of many microbes and allow better-adapted bacteria to flourish. Washing the skin can reduce the numbers of microflora on the skin but those remaining in hair follicles and sweat glands will soon re-establish normal populations.

3.1.3 Discuss the term pH in terms of its ability to describe the acidity of

a substance pH is a way of describing the acidity of a substance. pH is measured on a scale from 0 to 14. A pH of 7 is neutral. This means it is neither acidic nor alkaline. A low pH level shows high acidity. A strong acid has a pH range of 0 to 3. A weak acid has a pH of 3 to 7. A strong alkali (or base) has a pH range of 11 to 14. A weak alkali has a pH range from 7 to 11. The factors, which cause skin to have a naturally acidic pH, are:

• Sebum – the natural oil produced by glands in the skin. Sebum has a slightly acidic pH.

• Perspiration – the composition of sweat varies according to the stimulus that produced its secretion. Sweat produced by heat is more acidic than sweat in response to exercise. A ‘cold sweat’ that is secreted in response to intense excitement or fear has a more acidic pH.

• The skin is a secretory organ – it rids the body of water, urea and minerals in the form as sweat while providing temperature control for the body

• The skin protects the body from the outside environment – it provides a barrier against disease-causing bacteria

• The skin allows sufficient sunlight to penetrate fro the manufacture of vitamin D, while protecting the underlying tissues from damage

• The skin contains senses and transmit information about temperature and pressure


The skin consists of three layers – the underlying fatty material called subcutaneous tissue, the dermis layer and a thin outer layer called the epidermis. At the bottom of the epidermis is a layer of growing cells that continuously moves upwards to replace those above. Most of the cell division takes place at night and it takes a new cell between 40 to 56 days to reach the surface. By that time, the cell as died from lack of oxygen and food. These dead cells lie at the surface, flat and firmly attached to each other in a barrier called the stratum corneum, which protects the underlying cells and acts to prevent water loss from the body. The thicker dermis contains the sensory nerves, hair follicles, sweat and oil glands and blood vessels. The dermis has a plentiful supply of blood vessels that keep the tissues alive, but also assist in the regulation of body temperature. Each hair follicle contains several sebaceous glands that excrete an oily substance called sebum that controls the oiliness of the skin. Sensory nerves have their endings in the dermis and they also react to stimuli. The nerves can detect pain, temperature and pressure. Sweat glands are made up of a tube which soils at one end, then becomes a duct leading to the surface of the skin where it opens as a pore.

The action of microflora such as bacteria can change the pH of the skin. Sweat can also have a slightly alkaline pH. Respiration keeps us alive, but heat is released as a result of this process. In order to maintain a constant temperature of 37, the blood vessels and sweat glands of the skin help to maintain this constant temperature. When the body is too hot, the blood vessels dilate and fill with blood. This makes more blood flow to the surface of the skin and makes the cheeks and ears look flushed.

pH is measured using pH indicators such as litmus paper, pH meters or universal indicator. • Universal indicator – the

colours of the indicator helps you determine the ph. In acids, universal indicator turns red. In alkalis, universal indicator turns blue. Neutral is green. A colour chart helps you determine the actual pH.

• Indicator paper – litmus paper turns pink in acid and blue in alkali.

A range of skin and hair products can be tested with universal indicator: • Soap is alkaline – pH 9 or 10 • Shampoo is alkaline – pH 8.5 • Hair removal cream is alkaline – pH 11


3.1.4 Explain the relationship between the natural pH of the skin and the action of: - Microflora - Natural oil produced by glands in the skin - Perspiration

3.1.5 Identify and explain the use of common components of body

soaps, cleansers and shampoos and the reason for their use Skin Soaps – soap coats the skin in grease removing chemicals. Soap cleans because it consists of a hydrocarbon chain, which is repelled by water but attracted to oil, grease and dirt, a carboxylic (fatty) acid which is attracted to water. Therefore, soap is made by reacting sodium hydroxide with an animal or vegetable fat such as coconut oil. Skin soaps also contain colouring and perfume. Soaps are the water-soluble sodium or potassium salts of fatty acids. Soaps are made from fats or oil, or their fatty acids, which are treated with a strong alkali solution. Cleansers – common components include mineral oil, water and stearate. Most cleansers also contain a moisture absorber. Cleansers dissolve sebum and loosen particles of grim and dirt. Soaps are effective cleansers of the skin, removing sweat, chemicals and bacteria that cause body odours. Soaps are alkaline though, and strip away the acidic surface of the skin, leaving it feeling dry. Shampoos – extra chemicals in shampoo make the lather stay in the hair and remove grease. Sebum is produced by the sebaceous gland in each hair follicle. The sebum controls the loss of water from the hair that helps keep the hair soft and flexible, limit the growth of microorganisms and keep the hair smooth and shiny. Common components include coconut oil, some olive oil, alcohol, glycerol and water, detergent or soap and perfume. Sodium stearate (stearic acid) is used in soapless shampoos.

3.2.1 Perform a first-hand investigation to examine prepared slide of

human skin


3.2.2 Perform a first-hand investigation to measure the pH values of a range of skin and hair products

Aim: Compare the pH of a range of skin and hair products. Hypothesis: All the samples will have a similar pH because they are used on our body Equipment:

1. Dimple tile 2. Safety glasses 3. Universal indicator 4. Scale card 5. Paddle pop stick 6. Work Mat 7. Sample

Risk Assessment:

Possible Risk Ways to reduce risk Chemicals in the eye Safety glasses Ingestion Wash our hands Breaking equipment Use work mats, place equipment in centre of the

table

Variables: Independent – Sample Dependent – the pH Controlled – Same amount of indicator Method:

1. Place 3 samples of the selected product in the dimple tile 2. Place 3 drops of universal indicator in each sample 3. Stir with a paddle pop 4. Record

Results:


Discussion:

1. Evaluate the method. Our results could be affected with the size of each sample, as each sample size could be bigger or smaller than another. This could affect the colour and pH of the product sample.

2. Is your investigation reliable? Our investigation is somewhat reliable due to the fact we repeated the measuring of pH on each sample of product three times before coming to a conclusion. However, our results could be affected to the different sizes of sample, as there was no set weight or size.

3. Is your investigation valid? Yes, our investigation is valid. Our investigation is valid due to the amount of times we completed our investigation.

4. Graph the ‘average’ results.

Name of Product Colour pH Reading Trial Average pH

Acid or Alkaline 1 2 3 Foaming Cleanser

(Priceline) Orange

5 Orange

5 Orange

5 5 Acidic

Candy Pop Body Wash Orange 5 Orange

5 Orange

5 5 Acidic

Johnsons Baby Oil Orange 5 Orange

5 Orange

5 5 Acidic

Cancer Council Sunscreen Yellow 6 Yellow

6 Yellow

6 6 Acidic

Colgate Toothpaste Aqua 8 Aqua

8 Aqua

8 8 Alkaline

Candy Pop Hand Cream Orange 5 Orange

5 Orange

5 5 Acidic

Woolworths Select Refreshing Hand Soap

Orange 5

Orange 5

Orange 5 5 Acidic

Wella Conditioner Pink 4 Pink

4 Pink

4 4 Acidic

Pears 2 in 1 Shampoo and Conditioner

Red 3

Red 3

Red 3 3 Acidic

Candy Pop Body Frosting Orange 5 Orange

5 Orange

5 5 Acidic

Celique Blonde Shampoo Red 3 Red

3 Red

3 3 Acidic

Donna Bella Perfume Yellow 6 Yellow

6 Yellow

6 6 Acidic


5. Research: What is the recommended pH for body products? And why? The pH of body products should range from a pH level of 4.5 to 6.5 to compliment the pH level of the skin (pH of 5.5).

Conclusion: In conclusion our investigation shows that most of our tested products of a pH level of 5 or a level reading of close to 5. There were some products we found would not compliment the skin or hair. These products were Celique Blonde Shampoo and Pears 2 in 1 Shampoo and Conditioner. We found that the Toothpaste had a high pH reading.

3.2.3 Identify data sources, plan, choose equipment or resources for,

and perform first-hand investigation to test the manufacturer’s claim(s) in a commercial product such as soap, shampoo or shower gal and use the available evidence to analyse the results and discuss the validity of the claim(s)

Product 1: Imperial leather: Triple moisturising body wash Claim: Skin friendly pH Ingredients: Aqua, Sodium Laureth Sulfate, Sodium chloride, cocamidoprophy betaine, cocos nucifera (coconut oil), gardenia tahitensis (Tiarne) Flower extract, polyquaternium-7, parfum, citric acid, sodium benzoate, styre/acrylates copolymer, tetrasodium EDTA

Product 2: Imperial leather: Anti bacterial hand wash Claim: Skin friendly pH Ingredients: Aqua, sodium laureth sulfate, cocamidopropyl betaine, glycerine therobroma Cacao (cocoa), Seed butter, vanilla planifolia (vanilla), fruit extract, polyquaterium-7, parfum, benzophenone-1, cocamide MEA, glycol distearate, Laureth-4, lactic acid, laureth-10, methylchoroisthiazolinone, methylisothiazolinone, sodium chloride, sodium benzoate, tetrasodium EDTA, CL 19140, CL 14700

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Productused

pHofskinandhairproducts


4.1.1 Identify water and alcohol as commonly used solvents A solvent is a liquid used to dissolve a solute and form a solution. Water is a universal solvent. It is capable of dissolving more substances than any other solvent. Alcohol is another frequently used solvent. It is used as a solvent because of its ability to dissolve some substances that will not dissolve in water.

4.1.2 Explain the relationship between the properties of solvents and their use in cosmetics and external medications

Properties of solvents that affect their use in cosmetics and external medications include: • Ability to transport particular chemicals, (drugs, active ingredients) • Toxicity • Occlusiveness (ability to form an impermeable barrier).

Occlusiveness - Fats and oils are used as solvents in cosmetics and external medications because they occlude the skin. That is, substances like white soft paraffin (Vaseline) cover the skin and form a protective barrier (occlude the skin). A consequence of this is that the moisture in the skin is prevented from escaping. This causes the skin to rehydrate itself – that is absorb water. Also, this rehydration increases absorption of substances by the skin. Therefore drugs will be more readily absorbed when the skin (is occluded) is covered by fat and oil compounds. Toxicity - Water, by itself, is safe to use on the skin. It has a neutral pH and does not affect the skin’s acid mantle. The problem occurs with the substances used with, or dissolved in, the water. For example, just about all water based cosmetics and external medications need to have a preservative added. Unfortunately, these preservatives can be irritating to the skin for a significant number of people. Alcohol is also not toxic to the skin. However, the drying effect of alcohol can cause problems. Alcohol evaporates quite quickly from the skin. This drying effect can cause the population of beneficial micro flora to be significantly reduced. So, water and alcohol are used in cosmetics and external medications because they are non-toxic to the skin. Ability to transport particular chemicals - The main reason particular solvents are used in cosmetics or external medications is their ability to dissolve and transport chemicals.

• Chemicals that will dissolve in water include:

• Drugs such as: • Antiseptic – eg chlorohexidene in savlon • Local anaesthetic – eg lignocane • Anti-inflammatory – eg hydro-cortisone and • Substances like the water-soluble vitamins

• Substances that will dissolve in alcohol include: • Essential oils (substances that provide pleasant odour) • Drugs such as hydro quinone used for fading sunspots • Sunscreens - substances that absorb UV light


4.1.3 Identify cosmetics and external medications where water is the solvent

Water is used as a solvent for hair shampoo, moisturising creams, conditioners and hair gels. Water is used in substances that need to flow.

4.1.4 Identify cosmetics and external medications where alcohol is the

solvent Alcohol is used as a solvent for: • Aftershave lotion • Deodorants • Suntan oils • Spray deodorants • Face packs • Hair lacquers • Vapour rubs and menthol rubs such as Deep Heat • Nail polish and nail polish remover.

Alcohol evaporates quickly from the mixture to leave the solute on the skin or nails. Alcohol dissolves fat, and therefore can dry the hair and the skin when some products are used in excess. • For example, nail polish contains a resin, a plasticiser and

pigments in acetone. • When the nail polish dries the alcohol (acetone) evaporates,

leaving being the sticky solid that stays on the nail.

All organic solvents can be considered harmful and should be used with care. Organic solvents need to be used and stored in well-ventilated areas, and should not come in contact with the skin. If absorbed through the skin, solvents pass into the bloodstream and are filtered out by the kidneys and liver. Inhalations of solvent vapours can cause nose and throat irritation and damage to lung tissue. • Methylated spirits • Paint thinner or paint stripper

4.2.1 Perform an investigation to gather data comparing the rate at

which capsules, tablets, enteric-coated tablets, and slow-release tablets dissolve

Types of medications: 1. Simple hard tablet, usually white.( type taken 4 hourly eg.

Panadol) 2. Soluble white hard tablet. (Aspro clear) 3. True capsules (gelatine like mould on the outside) 4. Slow release (12hour cold preparation/ allergy) 5. Enteric-coated tablets (“plastic looking” coating) 6. Slow releases capsules (gelatine like capsule with different

coloured or size granules inside)


Aim: To compare the solubility of various medications. Materials:

• Panadol Rapid, Aspirin Tablets, Cartia (Enteric Coating), Fish Oil Capsules, Claratyne

• Distilled Water • 5 x (25ml) small Beakers • Thermometer • 10ml Measuring Cylinder • Stopwatch

Method: Part A:

1. Observe each form of medication and comment on its appearance, shape and mass.

2. Dissolve one tablet in 10ml of water (temperature 240 C –room temperature)

3. Record if the tablet dissolves and how long it takes for it to dissolve.

4. Repeat steps 1 and 2 twice more. 5. Repeat steps 2 -5 for the other three medication types

Part B: 1. Repeat the investigation for water at 370 C (body temperature)

Independent variable: Time it took to dissolve the tablet Dependent variable: The water Controlled variables: Amount of water used, temperature of water Result:

Example Pre

Appearance Purpose Time taken to

Dissolve Average Post

Appearance Water Temp

Panadol Oval, Hard, Large, Large Surface Area

Multipurpose Pain Relief

4.03 1.55 1.44 2.34 Opaque, White, Liquid Form, Suspension

24

Aspirin Small, Hard, White, Round

Reduce Fever and relieve mild to moderate pain

1.30 0.23 2.26 0.93 Transparent, Suspension, Liquid Form

24

Fish Oil Large, Oval, Transparent, Soft, Jelly, Brown

Cholesterol and blood pressure

0 0 0 0 Large, Oval, Transparent, Soft, Jelly, Brown

24

Cartia Small, Orange, Hard, Round

Thin the blood

0 2.12 4.44 3.6 Orange liquid, Suspension, Opaque

24

Claratyne Small, Oval, White, Hard

Hay Fever 1.43 0 0 1.43 Transparent, Cloudy, Suspension

24


Example Pre

Appearance Purpose Time Taken to

Dissolve Average Post

Appearance Water Temp

Panadol Oval, Hard, Large, Large Surface Area

Multipurpose Pain Relief

0.25 2.08 2.66 1.67 Opaque, White, Liquid Form, Suspension

37

Aspirin Small, Hard White, Round

Reduce fever and relieve mild to moderate pain

0.17 0.12 6.51 2.27 Transparent, Suspension, Liquid Form

37

Fish Oil Large, Oval, Transparent, Soft, Jelly, Brown

Cholesterol and blood pressure

8.00 9.30 9.53 8.94 Large, Oval, Transparent, Soft, Jelly, Brown

37

Cartia Small, Orange, Hard, Round

Thin the blood

5.20 7.20 13.0 8.47 Orange liquid, Suspension, Opaque

37

Claratyne Small, Oval, White, Hard

Hay Fever 1.07 1.14 0.21 0.81 Transparent, Cloudy, Suspension, Liquid

37

Discussion

1. Is your investigation reliable? Our investigation is reliable because we performed the experiment 3 times and we controlled the water temperature so it remained the same for all the experiment attempts.

2. Is your investigation valid? Yes – our investigation is valid. People would find that knowing how long it takes for their medication to dissolve to plan ahead and for how long to expect for pain-relief etc to start.

3. Discuss any problems or modifications that needed to be made. We found that everyone disagreed on what was considered ‘dissolved’ in terms of the medications dissolving in the water. This could have been prevented through an example first. Because of this, our times were quite different.

Conclusion: In conclusion we found that our experiment was successful. We found that the difference of water temperature affected the rate of which the medication dissolved. From what took over 20 minutes for our fish oil to dissolve in room temperature water (24 degrees), we found that placing the fish oil tablets in the body temperature water (37 degrees) allowed the fish oil to dissolve in an average of 8.94minutes. Our investigation was reliable because we completed the experiment 3 times in order to get an accurate time of which the medication dissolved.


4.2.2 Identify data sources, gather, process, analyse and present information from secondary sources to identify how subdermal implants release their medication into the body

• Transdermal patches allow for a small amount of the drug to be released constantly through the skin and into the blood stream. Transdermal patches are easy to use but have to be worn constantly.

• Ointments are mixtures for external use. Greasy preparations and water-in-oil emulsions and non-greasy preparations are oil-in-water. The base of the ointment is to be absorbed by the skin. The skin absorbs water-in-oil ointments.

• In a liniment the drug is placed in an oil, alcohol or soap solution that is rubbed on the skin.

Most Soluble Least Soluble

Capsules – liquid content Capsules – powder content Tablets Enteric – coated tablets Layered tablets Slow Release Tablets and Capsules

5.1.1 Identify the parts of the digestive system

Digestion is the process of converting large, complex organic molecules to smaller, simpler ones that can pass through cell membranes. To break down food, digestion must take place in two stages:

1. Mechanical digestion – this is the physical breaking up of large pieces of food into smaller pieces 2. Chemical digestion – this is the breakdown of large molecules into smaller molecules. Chemical digestion is achieved by enzymes which speed up the rate of chemicals reactions and cane be used again. Each type of food needs a different type of enzyme to break it down. • Mouth – digestion starts in your mouth. Mechanical digestion

occurs when you chew your food to break it up into smaller pieces. This increases the surface area, helping the digestive enzymes to reach more food molecules. When you chew, saliva from your salivary glands is missed with the food. The saliva wets the food so that it will slip down your throat. Saliva also contains an amylase enzyme that starts the digestion of starch.

• Oesophagus – the food then travels down into the part of the tube called the food pipe or oesophagus, which connects to your stomach. The food is squeezed down the oesophagus (and later through the intestines) by the contraction of muscles. This process is called peristalsis.


• Stomach – The stomach is a muscular bag where both mechanical and chemical digestion takes place. o Mechanical digestion takes

place in the stomach by the muscular contractions of the stomach walls. This helps to break down your food and mixes it with gastric juices.

o Chemical digestions takes place by the action of gastric juices, which is produced by some of the cells that line the wall of the stomach. Gastric juice contains protease enzymes, which digest proteins to amino acids.

o Other cells produce hydrochloric acid, which kills micro-organisms in food and helps the enzymes work

o Mucus produced by cells in the stomach wall stops the stomach from being digested by its own juices.

o After one to four hours the food is reduced to a fluid called chime, which is released slowly into the small intestine.

• Small Intestine – the small intestine is about 7m long in adults. The ‘small’ refers to the diameter of the tube. The top part of the small intestine is called the duodenum. In the duodenum: o Enzymes made by the pancreas (pancreatic juices) and the

intestinal juice from the walls of the intestine are added to the chyme. These juices help with the final chemical digestion of the food.

o Bile, a yellow-green liquid made in the liver and stored in the gall bladder, is added via the bile duct. Bile helps in the mechanical digestion of lipids.

o The digested food and enzymes are finally absorbed through millions of tiny finger-like projections called villi, which line the inside of the small intestine. They provide a large surface area for the absorption of soluble, digested food.

• Large Intestine – the material that passes from the small intestine into the large intestine consists of water and roughage (fibre) that cannot be digested by the enzymes in humans. As the material passes along the large intestine, water, vitamins and slats are absorbed, so the contents gradually become more solid. This solid material, called faeces, consists of undigested food and many bacterial cells. The faeces are stored in the last part of the intestine, called the rectum, before being expelled through the anus.


• Appendix – the appendix is a small tube with only one opening at the beginning of the large intestine. The appendix probably has no function in humans, but it is important in animals that eat grass. In herbivores it is enlarged into an organ called a caecum, which helps to digest cellulose.

5.1.2 Outline the role of the stomach and the small intestine in breaking

down food The role of the stomach includes:

• Storage of food. • Conversion of the food by gastric juices into a soft semi-fluid

mass that is released into the duodenum for transfer to the small intestine.

• Protein digestion. Food in the stomach is mixed with digestive juices called gastric juice. Gastric juice contains enzymes that begin the break down of proteins. Glands of the stomach also produce hydrochloric acid which provides the optimal pH for the action of the enzymes, and mucous which protects the walls of the stomach from the acidic juices.

• Only a small amount of water is absorbed in the stomach, and a few fat-soluble substances, such as alcohol and drugs, are absorbed.

The role of the small intestines includes: • The breakdown of food is completed in the small intestine. • Digestive juice from the pancreas and bile from the liver are

delivered through ducts to the small intestine. The wall of the small intestine produces other enzymes.

• In the small intestine, carbohydrates are converted to glucose and protein digestion is completed. Proteins are converted to amino acids.

• Some fats are converted to fatty acids and glycerol. • Most fats are emulsified by bile and are absorbed without

chemical change. • During the digestion process, most of the water is absorbed in

the duodenum and small intestine. Of the 5-10 litres of fluid that enters the small intestine, only half a litre reaches the large intestine.

• Pancreatic juice, containing enzymes such as amylases, proteases and lipases, is released into the small intestine via the pancreatic duct. The pancreas is a small, chilli shaped organ that produced pancreatic juice.

• Bile is added to the small intestine via a small tube called the bile duct. Bile is produced by the liver and stored in the gall bladder. Bile acts very much like a detergent and, like detergents, is strongly alkaline. Because bile is alkaline, it neutralises the stomach acid and this provides the best pH for the enzymes to work.

• The glands in the wall of the small intestine make intestinal juice.


5.1.3 Discuss the difference in pH of the stomach and the small intestine The glands of the stomach produce hydrochloric acid. Therefore, stomach contents are much more acidic – lower pH – than the contents in the small intestine which are alkaline. This is important in neutralising the contents from the stomach and in providing an optimum pH for the action of enzymes in the small intestine.

5.1.4 Explain why knowledge of the solubility of materials can be used to

design drugs for specific tasks There are many way in which drugs can be administered to the body:

• By mouth for absorption by the stomach or small intestine • By inhalation for absorption by the nasal passages and lungs • As a skin or dermal patch for absorption by the skin • By creams or ointments for protection of and absorption by the

outer layers of the skin • As suppositories for absorption by mucous membranes of the

rectum or vagina • By injection directly into the blood or muscle tissue • By drops (ear or eye) for absorption by the affected area

Depending on the rate of solubility of different drugs, different means of administration are more appropriate. For example, fast-acting drugs administered by inhalers are contained in aerosols or ‘puff’ powders and must be able to diffuse rapidly across the nasal cell membranes. Drugs given by the skin patches or muscle injection are absorbed by the body are slower rates. The rate depends on the substances in which the drugs is dissolved or suspended. A drug is a chemical substance, not normally required by the body, which alters the biological functioning of the body. The solubility of a drug affects where it is absorbed on or in the body. Many commonly available drugs are taken by mouth for absorption in the stomach or the small intestine. Water-soluble, fat-soluble and alcohol-soluble drugs are absorbed by the wall of the stomach into the bloodstream for distribution around the body (the drugs must not be affected by the pH of the stomach). The walls of the small intestine may also absorb water-soluble drugs. Absorption is the passage of the drug from the site of administration into the bloodstream. The solubility of a drug effects:

• How the body absorbs the drug • The rate of absorption • The action of the drug on and in the body • How the drug is administered and the site for administration

For example, some tablets and capsules have a coating that dissolves slowly and therefore remains intact for some hours after being taken in order to delay absorption and/or to ensure that the absorption occurs in the small intestine (rather than the stomach).


• Subdermal patches are often capsules implanted under the skin for slow absorption and long-lasting action. The drugs are absorbed at different rates, depending on the solvent in which they are dissolved or suspended.

• Ointments are mixtures for external use. Oil or fat based ointments are readily absorbed into the skin and may have paraffin, lanolin, hydrophilic petroleum jelly and polymers of ethylene glycol as their base. Greasy preparations are water-in-oil emulsions and non-greasy preparations are oil-in-water.

• Pastes are similar to ointments in that they are made from a base of glycogelatin, paraffin or starch and are stiffer, less greasy and more easily absorbed than ointments.

• Liniments usually consist of the drug in an oil, alcohol or soap solution, to be rubbed onto the skin.

• Jellies are made from and aqueous gel, such as acacia, cellulose derivatives, chondrus, gelatine or starch, as a base.

• Troches are lozenges which dissolve in the mouth. The active ingredients are slowly released from a base of sugar and gum, or gelatine.

• Syrups are aqueous solutions of the medication, sweetened with sugar.

• Suppositories are solid medicated tablets designed to be absorbed into the body through the lining of the rectum. Pessaries are suppositories for use in the vagina and bougies are for insertion into the urethra, nostrils or ears.

• Capsules, tablets, enteric-coated tablets and slow-release tablets

Drugs are often prescribed in different forms in order to control the rate at which they dissolve and therefore the rate at which they are released in the body and absorbed into the bloodstream.

• For example – aspirin, which is made up of acetyl salicylic acid, occurs in two forms – in acid solutions, which is fat-soluble, and in neutral or alkaline solution which is water-soluble. Acetyl salicylic acid in fat-soluble form easily diffuses through the stomach wall. However, aspirin can upset the stomach, so acetyl salicylic acid is also manufactured in a form that prevents it from dissolving until it reaches the small intestine.

Different forms of aspirin – Disprin capsules, aspirin tablets, Aspro clear (a soluble tablet), Cartia (an enteric-coated aspirin) and Fefol (delayed-release iron and folate capsules may be used. An enteric coating prevents the aspirin from being released in the stomach. The aspirin is released in the small intestine where it is absorbed slowly into the bloodstream.

• Capsules may be hard or soft. • Hard capsules contain powdered drugs in a shell or alcohol as

the solvent. • Semiliquid and liquid drugs can be enclosed in a soft capsule

with a gelatine shell.


• Long-acting capsules, for example, asthma medications, slowly release their contents into the patient’s intestinal tract.

• Enteric-coated capsules of tablets are coated with an polymer substance that will not dissolve in water or the acidic stomach juices, so that it will not break down until it has reached the small intestine.

• Tablets are by far the most common method of administering drugs. The drug is usually mixed with ingredients such as dextrin, lactose, starch or synthetic substances designed to ensure the drug disintegrates in the body.

• The mixture is then compressed in moulds to ensure a correct dose.

• Sugar coatings have to be applied in several coats and then polished, and so are more time consuming and costly than thin, transparent cellulose-derived coatings.

• Enteric coating will not dissolve in the stomach and the drugs dissolve in the more alkaline small intestine. Cellulose acetate phthalate is used as the coating.

• Layered tablets can also be made which incorporate two or more drugs which might be incompatible if formulated in the same tablet.

5.1.5 Account for the absorption of a drug and its action on/in the body in terms of its solubility

Pharmacology is the science of the nature and properties of drugs and their actions in the body. There are a large number of factors to be considered in the design of effective drugs. For a drug to be effective it needs to be:

• Absorbed • Distributed through the body and then • Interact with receptors in the target area (act on the body).

An important factor for the absorption, distribution and action of a drug is solubility. This solubility may refer to the solubility of the drug itself or the chemical carrier of the drug. Absorption is the movement of a drug from the site of administration into the blood. In the blood the drugs are either dissolved in blood plasma or attached to proteins in the blood. At the site of action the drug becomes attached to a receptor compound to carry out its function.

Oral intake of drugs

• The drug must be water-soluble and therefore dissolve in the stomach or small intestine before absorption can occur.

• Then the drug must cross several cell membranes ot the stomach and/or intestine walls to reach the circulatory system (capillary - blood vessel). These membranes are mainly made up of lipids (a group of fat and fat-like substances). To cross this barrier the drug needs to be lipid soluble. In water-soluble form, drugs cannot pass through the lipid membranes.


• Once in the blood the drug is again in a water-soluble form and is then transported around the body. Alternatively, the drug is transported in the blood attached to a protein molecule.

• Finally, at the site of action the drug may again need to move across several cell membranes. Again it may need to return to its lipid soluble form to pass across this biological barrier.

5.1.6 Identify that the manner of administration of a drug may be related

to its solubility Depending on the rate of solubility of different drugs, different means of administration are more appropriate. For example, fast-acting drugs administered by inhalers are contained in aerosols or “puff” powders and must be able to diffuse rapidly across the nasal cell membranes. Drugs given by the skin patches or muscle injection are absorbed y the body at slower rates. The rate depends on the substance in which the drug is dissolved or suspended.

• By mouth for absorption by the stomach or small intestine • By inhalation for absorption by the nasal passages and lungs • As a skin or dermal patch for absorption by the skin • By creams or ointments for protection of and absorption by the

outer layers of the skin • As suppositories for absorption by the mucous membranes of

the rectum or vagina • By injection directly into the blood or muscle tissue • By drops, such as ear and eye drops, for absorption by the

affected tissue 5.1.7 Identify vitamins that are water-soluble and those that are fat-

soluble Vitamins are divided into two categories: fat-soluble and water-soluble. Fat-soluble: are vitamins A, D, E and K. Because they are fat-soluble, they can be stored in body tissues. Water-soluble: are B1 (thiamine), B2 (Riboflavin), Niacin, B6 (pyridoxine), pantothenic acid, biotin, B12, folate (folic acid), and vitamin C. These must be consumed daily because the body will excrete them in the urine rather than storing them.


5.2.1 Gather, process and analyse information from the first-hand or secondary sources to relate the significance of solubility of medication to its action on/in the body

Aim: • Compare the solubility of different medications in an acid and a

base

Equipment: • HCl (hydrochloric acid) acid in stomach • NaOH (sodium hydroxide) base in small intestine • 30 x test tubes • 4 x beaker • Water (37 degrees) • 4 x 10ml measuring cylinder • 1 x kettle • 2 x thermometer • 10 x stopwatches • Safety glasses • Work mat • Tablets: (x 6)

a. Soluble tablet b. Tablet c. Enteric coated (Cartia) d. Slow release (Claratyne) e. Capsule

Risk Assessment:

Method:

1. Boil water 2. Pour boiling water into beaker 3. Pour 5ml of HCl or NaOH into test tubes 4. Place test tubes into beaker with HCl or NaOH at 37 degrees

(use thermometer) 5. Place one of the 4 tablets into each of the 4 test tubes 6. Record with stopwatches, the time taken to dissolve

Possible Risk: Ways to Reduce: - Chemical in eyes - Safety glasses - Chemical

burn/water - Chemicals in dropper bottles - Small amount of chemicals - Tidy work area - Teacher supervision of use of hot

water - Ingestion - Wash hands after practical work


Tablet HCl NaOH Time taken to

dissolve (sec – min) Average Time taken to

dissolve (sec – min) Average

1 2 3 1 2 3 Aspirin (Tablet)

0.21 0.15 0.15 0.17 0.31 0.28 0.27 0.28

Aspro Clear (Soluble)

0.02 0.02 0.03 0.02 0.04 0.06 0.03 0.043

Fish Oil Tablets

(Capsule)

9.40 9.26 9.24 9.30 10.30 10.48 10.40 10.39

Cartia (Enteric coated)

20.0+ 20.0+ 20.0+ 20.00+ 8.04 12.57 15.36 11.99


Medical Technology: Bionics


1.1.1 Identify parts of the body and the biomaterials and biomedical devices that can be used to replace damaged or diseased body parts including: - Pins, screws and plates - Artificial joints - Pacemakers - Artificial valves - Crowns and dentures - Lenses - Prosthetic limbs - Cochlear implants

Some of the devices, which can be used to replace damaged or diseased body parts include:

• Pins, screws and plates – these are sued to replace damaged bones and repair joints: for example, titanium plates are inserted into damaged skulls to protect the brain; titanium-coated stainless steel bone pins are used to repair severe bone fractures: hip screws are used to stabilise fractures of the neck or the thigh bone(the femur).

• Artificial joints – such as artificial knee, hip, shoulder, wrist and elbow joints.

• Pacemaker implants – electronic devices that send a series of small electric impulses to the heat causing it to beat regularly.

• Cochlear implants – a cochlear implant is an artificial hearing device. It is sometimes called a bionic ear. Cochlear implants were developed to bypass dead hair cells and electronically stimulate the auditory nerve directly. They consist of three main components: the cochlear implant package and receiver-stimulator, a speech processor and a headset. The receiver is implanted in the patient’s skull. A microphone behind the patient’s ear picks up sounds. These are passed to as sound processor usually worn in a belt or in a jacket. The processor highlights important works making them easier to understand. The processor then transmits the signals to the receiver.

• Artificial valves – heart disease can lead to narrowing or leakage of heart valves. Heart valves can also become stiff. Faulty heart valves can be replaces with biological valves from a human donor or the valve from a pig’s heart. Bionic mechanical valves can also be used.

• Crowns and dentures – dentures are artificial teeth. The teeth are made of metal covered in porcelain. The teeth are set in plastic gums.

• Lenses – contact lenses and intraocular lenses. The lens of the eye growing cloudy and eventually becoming opaque causes cataracts. Opaque areas of the lens prevent light from reaching the retina and the sufferer becomes bling. Cataract surgery involves replacing the damaged or cloudy lens with an intraocular lens.


• Prosthetic limbs – artificial limbs such as arms/hand and legs/feet. Artificial body parts are also called prostheses. Myoelectric prosthetic limbs use electric signals from the patient’s muscles to move the limb. Computers are now used to design tailor-made models for amputees.

1.2.1 Gather and process information from secondary sources to trace

the historical development of on of the following implants: - Cochlear implants - Artificial valves

Artificial valves – the first implantable artificial valve was invented in 1952. It was not until the invention of the heart-lung machine, however, that surgeons could safely enter the heart and repair or replace parts. In 1961, the first successful replacement for the human vitral valve was implanted. The valve was made from a steel cage enclosing a silicon rubber ball.

2.1.1 Explain the relationship

between the structure and function of the following parts of the heart: - Valves - Atria - Ventricles - Major arteries and veins

The heart is made up of valves, the left and right atria and the left and right ventricles. Blood vessels, veins and arteries, carry blood to and from the heart.

• Valves – the flaps in the heart are called valves. Valves ensure a one-way flow of blood. The valves between the aria and ventricles prevent the blood flowing back into the aria as the ventricles contract. The valves in the arteries prevent the blood that leaves the heart from flowing back into the ventricles.

• Atria – the in-flow chambers. The atria collect the incoming blood and, when they contract, transfer the blood to the ventricles.

• Ventricles – the out-flow chambers. When the ventricles contract, blood is pumped away from the heart.


Deoxygenated blood flows through the veins into the right atrium then into the right ventricles where it is squeezed out to the lungs to pick up oxygen. From the lungs, oxygenated blood flows into the left atrium, then into the left ventricle and then out to the rest of the body via arteries. The chambers of the heart have thick muscular walls made up of cardiac muscle.

• Major arteries and veins – include the aorta, the pulmonary artery and the pulmonary vein, the vena cava and the coronary artery.

• Arteries – carry blood away from the heart. The blood is pumped under pressure. Therefore, arteries have thick muscular walls.

• Veins – carry blood to the heart. Blood flows through veins under low pressure. Veins have thick walls. The movement of blood in veins is assisted by the contraction of body muscles. Valves in veins prevent back-flow of blood. (There are no valves in the arteries).

• The aorta and pulmonary artery are the major arteries of the heart. The aorta takes blood from the left ventricles to blood vessels that go to the rest of the body. The pulmonary artery takes blood from the right ventricles to the lungs. Two main arteries called the coronary arteries lead from the aorta to supply the heart muscle itself with blood.

• The caval veins and the pulmonary vein are the major veins of the heat. During the relaxing phase, deoxygenated blood laden with carbon dioxide and other wastes, returns to the right side of the heart. This blood enters the right atrium via two large veins – the superior vena cava (from the head, neck and arms) and the inferior vena cava (from the abdomen, pelvis and lower limbs). Blood returns from the lungs to the left atrium via the pulmonary vein.

2.1.2 Explain the specialised tissues in the heart procedure an electrical

signal that stimulates rhythmic contractions of the cardiac muscle The heart is the pumping centre for blood. The rhythmic pumping is the heartbeat. Cardiac muscle contract and relaxes involuntarily (we do not consciously think about it). The heart muscles pump every second of a person’s life. The heart beats about 70 times per second – 100,000 thousand times per day. In one day, the heart pumps the body’s supply of blood through the whole circulatory system. The electrical signal starts in the sinoatrial node. After the impulse starts, it quickly travels from cell to cell in the muscles of the atrium, causing it to contract just before the ventricle does. Special cells delay the impulse long enough for the atrial contraction to fill the ventricle with blood. As the impulse moves through, the chambers relax. A stethoscope is used to listen to the sounds from the heart (and lungs). The heart contracts in the systole phase and relaxes in the diastole phase.


2.1.3 Discuss the problems that can result from interruptions to the normal rhythm of the heart Problems that can result from interruptions to the normal rhythm of the heart include an irregular heartbeat called arrhythmia. Arrhythmia can be detected using an electrocardiogram. Fibrillations are a type of arrhythmia. The heart fibrillates when individual muscle fibres of the heart’s ventricles beat quickly and chaotically (at a rate of more than 100 beats per minute). Many patients with pacemakers suffer from arrhythmia in which the heart beats too slowly. This is usually due to deterioration in the heart’s natural pacemaker as a person ages. Pacemakers are electronic devices implanted under the skin of the chest. An artificial pacemaker helps to produce a regular electrical impulse, and therefore a regular heartbeat.

Heart Murmur (noisy abnormal blood flow) The rhythmic closing of the heart valves causes the familiar ‘lub-dub’ sound of the heartbeat as blood is pumped in and out of the chambers. A heart murmur is a whooshing, humming, or rasping sound between the heartbeat sounds. Cause

• This is caused by noisy blood flow within the heart. Blood can flow abnormally through the heart for many reasons, including: • Congenital heart disorders – during fetal development, the

heart and blood vessels fail to grow properly. Passage of blood inside the heart or vessels may be blocked, blood travels abnormally through heart valves or heart itself may be underdeveloped

• Mitral regurgitation – the mitral valve separates the left atrium from the left ventricle. Mitral regurgitation means the mitral valve doesn’t close properly, allowing blood to backtrack into the atrium

• Anaemia – the bloods inability to deliver sufficient oxygen to the cells. The heart pumps the blood around faster to supply the body’s demand for oxygen and other substances

Symptoms • Pains in the chest • Accelerated heart rate (tachycardia) • Heart palpitations/breathlessness • Fatigue • Cyanosis (blue tinge to the skin caused by lack of oxygen)

Treatment • Treatment depends on the cause:

• Innocent heart murmurs – no treatment necessary • Heart surgery – to repair leaking valves or repair structural

abnormalities of congenital heart disorders


• Anaemia – treated with iron supplements and changes to diet. Serious cases include blood transfusions or removal of the spleen

Ischemia (reduced blood flow) Ischemia is any reduction in blood flow resulting in decreased oxygen and nutrient supplies to a tissue. It can occur anywhere in the body and heart attacks and strokes can occur as a result of this. It is a condition that affects the supply of blood to the heart. Cause

• The major risk factors are smoking, diabetes and cholesterol levels

• Hypertension is also a risk factor in the development of Ischaemic Heart Disease

• Genetic and hereditary factors may also be responsible for the disease

Symptoms • Angina • Acute chest pain • Heart failure

• difficulty in breathing or swelling of the extremities due to weakness of the heart muscle

Treatment • Organic nitrates • Aspirin • Calcium channel blockers • Reduce coronary flow • Beta blockers

• reduce cardiac work and oxygen consumption

Fibrillation (irregular heart beat) Atrial fibrillation (AF) is a type of arrhythmia, which means that the heart beats fast and irregularly. The risk of AF increases with age. Without treatment, the risk of a fatal stroke or heart attack is high. Three main types of AF:

• One-off: the heart has a single episode of irregular beating • Occasional: the heart is prone to repeat episodes of irregular

beating, for short periods of time • Persistent: the heart beats irregularly all the time

Cause • Caused by a distortion of electrical messages that control the

steady rhythm of the heart. AF is commonly triggered by another chronic illness or event that irritates the heart, including: • Chronic high blood pressure • Coronary heart disease • Chest surgery • Chest trauma • Excessive intake of ‘social’ drugs such as caffeine and

alcohol


• Certain illnesses such as pneumonia Symptoms

• Sensations of a fluttering heartbeat (palpitations) • Irregular heartbeat • Angina (chest pain) • Dizziness • Inability to tolerate exercise • Fainting spells

Treatment • Treatment depends on many factors including the severity of the

condition, person’s age and general health. The longer the person has been experiencing AF, the less effective non-invasive treatments (such as medications) will be.

• Treatment options may include: • Medications – to normalise the heart’s rhythm, slow the

heart rate or reduce the risk of stroke • Electrical shock therapy to the heart – resets the hearts

electrical system Tachycardia (abnormally rapid heart rate) The upper and lower chambers of the heart beat significantly faster and pumps less efficiently, reducing blood flow to the rest of the body and the heart itself. The faster heartbeat increases in demand for oxygen, increasing the risk of stroke and sudden cardiac arrest or even death. 60 – 100 beats per minute Cause

• Disruption in the normal electrical impulses that control the rate at which our heart pumps

• Heart-related conditions such as high blood pressure (hypertension)

• Poor blood supply to the heart muscle due to coronary artery disease

• Alcohol or drug abuse • Emotional stress • Thyroid disease and certain lung diseases

Symptoms • Shortness of breath • Dizziness • Sudden weakness • Fluttering in the chest • Light-headedness • Fainting

Treatment • Fever: fever reducing medications • Blood loss: intravenous fluids or blood transfusions • Lung disease: blood clot removal medications • Radiation or surgical procedures, massages and timed electrical

shocks


Bradycardia (abnormally slow heart rate) Bradycardia is an abnormally slow heart rate of less than 60 beats per minute. Bradycardia can be a form of cardiac arrhythmia, a heart-rate abnormality cause by a problem in the sinus node, or it can be related to some disturbance in the passage of heartbeat signals. Cause • Changes in the heart that are the result of aging • Diseases that damage the hearts electrical system e.g. heart

attack, coronary artery disease • Too much potassium in the blood can slow electrical impulses

through the heart Symptoms

• Dizziness • Weakness • Lack of energy • Fainting spells

Treatment • Regular exercise improves the hearts ability to pump blood

efficiently • Permanent pacemaker

2.1.4 Identify that a pacemaker will produce a regular electrical impulse

A pacemaker consists of three parts: a battery powered generator, circuitry and wires that connect it to the heart. The generator is usually implanted just beneath the skin below the collarbone. The leads are threaded into position through the veins in a titanium or titanium alloy case. The lead is made of a metal alloy insulated by a plastic such as polyurethane. The circuitry is usually made of silicon semiconductors. The material used to construct pacemakers must be biocompatible, inert, non-toxic and able to be sterilised. For example – titanium is suitable for implanting because it is a strong, light, biocompatible material. Early ‘pacemakers’ delivered an electric shock to the heart of a person in an emergency, such as having a heart attack. The device was plugged into a wall socket. Some of the technological advances that led to the development of the modern day pacemaker include:

• Devices that reduced the amount of voltage and increased the length of time of the electronic pacing.

• Pacemakers with leads attached directly to the outer wall of the heart.

• Portable devices, which used a battery as the power source. An Australian physician, Mark Lidwill, together with physicist Edgar Booth, is credited with inventing the first portable pace-making unit, demonstrated in 1931 (although there is some debate about this).


• Devices which could be surgically implanted (rather than being worn externally). The first artificial pacemaker was implanted in 1958.

• Techniques for inserting the lead from a pacemaker into a vein and threading the lead into the heart chamber.

• Development of smaller pacemaker units. • Improvements in design, electrical circuitry, longer lasting

batteries and computer technology. A microprocessor is used in modern pacemakers. This means that the pacemaker can be programmed and monitored from outside the patient’s body. The most common pacemaker monitors the heart’s activity and takes control only when the heart rate falls below a programed minimum, usually 60 beats.

2.1.5 Identify the types of materials used to make pacemakers and the

properties that make these suitable for implanting in the body A pacemaker consists of three parts: a battery powered generator, circuitry and wires that connect it to the heart. The generator is usually implanted just beneath the skin below the collarbone. The leads are threaded into position through the veins leading back to the heart. The pacemaker is sealed in a titanium or titanium alloy case. The lead is made of metal insulated by plastic such as polyurethane. The circuitry is usually made of silicon semiconductors. The material used to construct pacemakers must be biocompatible, inert, non-toxic and able to be sterilised. For example, titanium is suitable for implanting because it is strong, light and biocompatible.

2.1.6 Describe the problems that can result from faulty valves in the

heart With a leaky or faulty valve(s), the heart must work harder, which can cause a heart attack or death. If valves leak, a heart murmur is heard. Symptoms of a faulty valve include shortness of breath during exercise, tiredness, a continual cough and occasional chest pain. When heart valves become inflamed, this can result in adhesions causing scar tissue, which fuses part of the valves together. Rheumatic fever (can auto-immune disease initiated by a bacterial infection) is the most common cause of this type of valve damage, particularly the mitral valve. Types of artificial valves include the bileaflet valve, the tilting disc valve and ball-and-cage valve. The bileaflet valve consists of two semi-circular carbon discs which open and close. The ball-and-cage valve consists of a metal housing with carbon discs. Artificial calves are more durable than biological valves, but need anti-coagulant to prevent blood clots forming around the implant.


Biological valves include valves from a human or modified from a pig donor. Pig valves are similar to humans. They do not cause blood clots (as mechanical valves do) but they only have a working life of 7 to 10 years before the tissue degenerates. The use of pig donor tissue for human transplants is currently being reconsidered following concerns that diseases (such as deadly viruses) can be transferred to humans by implanting pig tissue.

2.1.7 Describe the properties of materials such as Teflon/pyrolytic

carbon that make them versatile materials for making artificial body parts, including heart valves

Materials such as Teflon or pyrolytic carbon must be biocompatible, that is, not rejected by the body’s immune system. Teflon is used for artificial blood vessels because it is elastic, porous and strong. It functions like real blood vessels, dilating and contracting with changing blood flow. Other biocompatible materials include titanium, titanium coated stainless steel, platinum, cobalt, chromium alloys and silicone. New research in Australia is aiming to develop new polymers that can be used in a range of biomedical devices including valves. The research aims to combine the strength and good mechanical performance of polyurethane with the flexibility and biostability of silicone.

2.1.8 Describe and explain the effects of a build-up of plaque on the

walls of major arteries and veins on blood flow to and from the heart

One of the main causes of heart (cardiovascular) disease is the build up of plaque on the inside of the walls of major arteries and veins. The plaque is made of deposits of fat (cholesterol) and other substances. If plaque builds up sufficiently it can:

• Cause the walls of the artery or vein to become weakened, to bulge or split.

• Block the blood vessel(s) completely. If the coronary arteries become blocked, this results in a heart attack.

2.1.9 Discuss ways in which plaque could be eliminated or altered to

ease blood flow Since the mid 1980s, surgeons have developed and refined techniques for easing blood flow in weakened and blocked blood vessels. The technique is called angioplasty. Balloon angioplasty is used to improve blood flow by widening the artery. A small cut is made is the arm or groin. A thin plastic tube is inserted into an artery and pushed to the blocked blood vessel. A catheter containing a small balloon is threaded through the tube until it reaches the blockage. When the balloon is inflated it pushes the plaque against the artery wall and the diameter is widened. Balloons are also used to widen the mitral and aortic valves in the heart. Laser angioplasty uses a laser beam to remove plaque from blood vessels. This was initially done during bypass surgery. Surgeons now use minimally invasive techniques such as percutaneous laser


angioplasty to remove plaque. A catheter containing the laser is pushed under the skin. The decision to use particular technique is based to some extent on the degree to which the blood vessel(s) is blocked. The plaque can be eliminated or altered by:

• Removing the diseased blood vessel and replacing it with an artificial blood vessel or a vein from the patient’s leg.

• Removing the plaque using a laser beam. Bypass surgery – this involves taking a vein from the patients leg and using it to construct a new pathway for blood to flow around the blocked vessel. Replacing the blocked vessel with an artificial valve – a woven plastic artificial graft is soaked in blood and then sewn in place. Body cells (fibroblasts) invade the artificial structure ad eventually it becomes ‘normal’ tissue.

2.2.1 Gather, identify data sources,

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