Understanding Ourselves
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Transcript of Understanding Ourselves
04/22/23
Understanding Understanding OurselvesOurselves
W Richards
The Weald School
(OCR)
04/22/23Body systemsBody systems
The RESPIRATORY SYSTEM: takes in _____
The DIGESTIVE SYSTEM: takes in ________
The ___________ SYSTEM: transports oxygen and glucose around the body
The SKELETAL and MUSCULAR systems: use the _____ from glucose to allow ________
Words – energy, movement, oxygen, glucose, circulatory
04/22/23CirculationCirculation1) Blood gets pumped from the heart to the lungs and picks up oxygen
2) The blood is then taken back to the heart…
3) The heart pumps the blood to the intestine (where oxygen and glucose are removed)…
4) … and to the rest of the body (where oxygen is removed)
5) After the oxygen and glucose have been removed for respiration the blood is sent back to the heart and starts again
04/22/23The Circulatory systemThe Circulatory systemThe circulatory system is responsible for pumping ______ around the body. We need blood to be taken around the body because blood contains ________ and _______. These are needed so that all the ____ in our bodies can produce _____ through _________.
Blood is pumped at high pressure. Blood pressure is measured in mmHg (millimetres of ______). Normal pressure is about 120/80 mmHg.Words – energy, mercury, blood,
glucose, respiration, oxygen, cells
04/22/23High Blood PressureHigh Blood PressureHigh blood pressure is a condition where the ______ and blood vessels experience extra strain. It can be caused by:
• Excess weight• High stress levels• _____• Excess _______• Diets that are high in saturated ___, sugar or salt
Long term high blood pressure can cause blood vessels to weaken or even ______.
Words – alcohol, burst, smoking, heart, fat
04/22/23(Aerobic) Respiration(Aerobic) Respiration
Words – breathing, energy, Mrs Gren, respiration, food
A while ago we learnt about ___ ______. Each of these life processes needs ENERGY. ___________ is the process our bodies use to produce this energy:
The glucose we need comes from ______ and the oxygen from _________. Water and carbon dioxide are breathed out. The MAIN product of this equation is _________.
Glucose + oxygen water + carbon dioxide + ENERGYC6H12O6 + 6O2 6H20 + 6CO2 + energy
04/22/23Anaerobic respirationAnaerobic respirationUnlike aerobic respiration, anaerobic respiration is when energy is provided WITHOUT needing _________:
This happens when the body can’t provide oxygen quick enough for __________ respiration to take place.
Anaerobic respiration produces energy much _______ than aerobic respiration but only produces 1/20th as much.
Lactic acid is also produced, and this can build up in muscles causing ______ and an oxygen ______.
This “debt” then needs to be “repaid” by deep breathing to ________ the lactic acid.
Words – debt, oxygen, fatigue, oxidise, aerobic, quicker
Glucose lactic acid + a bit of energy
04/22/23The Effect of Exercise The Effect of Exercise Heart rate/min
Breathing
rate/min10075
50
25
225
17512575
5 mins 10 mins 15 mins 20 mins
Rest Exercise Recovery
04/22/23Balanced dietBalanced dietA balanced diet should contain fats, proteins and carbohydrates in roughly these amounts:
It should also contain water, vitamins, minerals and fibre.
04/22/23Modern diets and health Modern diets and health problemsproblems
% obesity in the UK
04/22/23Poor dietsPoor dietsIf we don’t have a balanced diet we may suffer form a “deficiency symptom”:
Vitamin D
Protein
Vitamin C
Vitamin A
Iron
Calcium
Anaemia
Scurvy (bleeding gums and joints)
Weak bones and teeth
Wasting of body tissue
Rickets
Poor night vision
Lack of… Causes…
04/22/23Metabolic Rate and healthMetabolic Rate and healthThe rate at which our bodies carry out chemical reactions is called the “metabolic rate”. This rate varies with:• The amount of work we do• The amount of fat in our body• Inherited factors
Condition How this affects our health
Lack of exerciseFatty dietsWarm weatherUsing cars instead of walkingPlaying XBox instead of football
04/22/23Body-Mass IndexBody-Mass IndexA commonly-used way to indicate is someone is overweight or underweight is the Body Mass Index (BMI):
BMI = Mass (kg)Height2 (m2)
BMI Meaning<18.5 Underweight
18.5-25 Ideal25-30 Overweight30-40 Obese
04/22/23ProteinProteinProteins are long chains of amino acids. There are two main types of these:• Essential amino acids (must be eaten)• Non-essential amino acids (can be made in the body)
Meat and fish are “first class” proteins
People who do not eat enough protein will not grow properly. Protein deficiency can result in a disease called kwasiorkor, where the muscles waste away and the belly swells.
How much protein should we eat?
RDA of protein (in g) = 0.75 x body mass (in kg)
04/22/23Eating disordersEating disordersAnorexia nervosa – this is a condition where sufferers restrict what they eat and sometimes starve themselves, leading to possible weight loss, abdominal pains, discoloured skin, irregular periods etc.
Bulimia nervosa – this is when people vomit or take laxatives straight after eating to get the food out as quickly as possible. It can lead to weight fluctuations, poor skin, hair loss, irregular periods, tiredness etc.
04/22/23The digestive systemThe digestive systemThe whole point of digestion is to break down our food so that we can get the bits we need from it…
The main foods affected are CARBOHYDRATES – these are broken down into GLUCOSE.
Hydrochloric acid is produced in the stomach to kill bacteria. Digestion also depends on “enzymes”...
04/22/23EnzymesEnzymesEnzymes are chemicals produced by the body to help _______. When they react with food they break it down into ______ pieces which can then pass into the ______:Carbohydrase (produced in the mouth, pancreas and small intestine) breaks _______ (a carbohydrate) down into glucose:Protease (produced in the stomach, pancreas and small intestine) breaks _______ down into amino acids:
Lipase (produced in the pancreas and small intestine) breaks fats (_____) down into fatty acids and glycerol:
Words – blood, lipids, proteins, digestion, starch, smaller
Bloo
dstre
am
04/22/23Bile and the liverBile and the liverBile is a chemical produced in
the liver and stored in the gall bladder. It has 2 functions:
1) It neutralises stomach acid and produces alkaline conditions for enzymes to work in
2) It emulsifies (“breaks down” fats:
Fat globules
Fat droplets
04/22/23DiseaseDiseaseA disease is any condition where the body does not work properly. It can be caused by a number of things:
• A spread of infection from another person (an “infectious disease”, e.g. A cold)• Poor diets (e.g. Scurvy)• Organ malfunction (e.g. Diabetes)• Genetic inheritance (e.g. Colour blindness)• Mutations in cells (tumours, e.g. Cancer) – these can be caused by smoking, drinking, too much sun etc
04/22/23PathogensPathogensPathogens are microbes (micro organisms) that can cause diseases. They can enter the body in a number of ways:
…or other natural openings…
They can be breathed in through the mouth or nose
They can enter through cuts or bites in the skin
04/22/23DiseaseDiseaseA disease is any condition where the body isn’t working as it should. This could be caused by a malfunction in the body (as with diabetes) or it could be caused by a type of pathogen:
VirusesBacteria
• 1/1000th mm big• Living cells (some are harmless)• Grow very quickly• Affected by antibiotics• Examples: food poisoning, tetanus, sore throats
• 1/1,000,000th mm big• Genetic info inside a protein coat• Not affected by antibiotics• Release poisons• Examples: colds, flu, polio, chicken pox
04/22/23Using AntibioticsUsing AntibioticsAntibiotics can be used to kill bacteria. However, there
are two problems: 1) Overuse of antibiotics can lead
to bacteria becoming resistant (e.g. the MRSA “superbug”). This means that antibiotics must be used sparingly.
2) Antibiotics have no effect on a virus, like the common cold. It is difficult to kill a virus without damaging body tissue. A virus is usually allowed to “run its course”.
04/22/23FungiFungiFungi can also cause unwanted conditions. These conditions can be treated with anti-fungal medicine and antibiotics. Some examples (don’t look if you’re faint hearted!):
04/22/23Transmitting DiseasesTransmitting DiseasesPathogens can be transmitted in a number of ways:
1) “Horizontal transmission” (directly ______ an ill person)2) “Vehicle transmission” (touching an ill person’s
________)3) “Vertical transmission” (mother to ____)4) Airborne (______ in the air)5) Vector-borne (third party, e.g. __________)
Words – mosquitoes, belongings, touching, baby, germs
04/22/23MalariaMalaria
04/22/23Microbes: our defence against Microbes: our defence against themthem
Our bodies have defence mechanisms against invading microbes:
If our skin is cut platelets seal the wound by clotting
The breathing organs have hairs and produce mucus to cover the lining of these organs and trap the microbes
The skin acts as a waterproof barrier
Our blood contains white blood cells
Tears contain lysozyme, an enzyme that kills bacteria
04/22/23Cleaning our airCleaning our airOur respiratory system has two types of specialised cell that help to keep our lungs clean:
1. Mucus is produced and traps dust, bacteria etc
2. The mucus is swept upwards to the mouth by cilia (cells with tiny hairs)
04/22/23White blood cellsWhite blood cellsIf microbes enter our body they need to be neutralised or killed. This is done by WHITE BLOOD CELLS:
White blood cells do 3 things:1) They eat the microbe (these
white blood cells are called “phagocytes”)
2) They produce antibodies to neutralise the microbe (“lymphocytes”)
3) The produce antitoxins to neutralise the poisons produced by microbes (lymphocytes again)
04/22/23Producing antibodiesProducing antibodies
Step 1: The lymphocyte “sees” the pathogen (microbe)
Step 2: The cell produces antibodies to “fit” the pathogen
Step 3: The antibodies fit onto the pathogens and cause them to “clump”
Step 4: The pathogens are “eaten” by the white blood cells
You’re going down
04/22/23Specific antibodiesSpecific antibodies
Antibodies are specific – they will neutralise the microbe they have been made for.
04/22/23Fighting diseaseFighting diseaseNATURAL IMMUNITYThis is when antibodies are produced by a person when needed or they are passed on by the mother during pregnancy.
ARTIFICIAL IMMUNITYCan be done in two ways:1) A vaccine with dead microbes is
injected – the body is “tricked” into producing antibodies ready for the real thing. This is called ACTIVE IMMUNISATION
2) The antibodies are injected directly into the body – this is called PASSIVE IMMUNISATION.
04/22/23VaccinationsVaccinationsSome people argue that the MMR vaccine is a good idea, others think it is a bad idea. Briefly summarise each side of the argument:
MMR vaccine
For Against
04/22/23Researching new medicinesResearching new medicinesBefore new drugs can be approved they have to go through three stages:
3. Does it work? People with the illness are tested on. This can involve using a “placebo” – a dummy pill
1. Is it toxic? Tests are done on animals
2. Is it safe for humans? Human volunteers trial the drug
04/22/23The Nervous SystemThe Nervous SystemThe CENTRAL NERVOUS SYSTEM (CNS) enables us to react to our surroundings. It consists mainly of the brain, the spinal chord, nerve cells (“neurones”) and receptors.
Types of receptor:1) Light receptors in the eyes2) Sound receptors in the ears3) Taste receptors on the tongue4) Smell receptors in the nose5) Touch, pressure and temperature receptors in the skin6) Changes of position receptors in the ears (balance)
04/22/23Nervous ReactionsNervous ReactionsWhen we react to a stimulus our bodies use the following pattern:
Stimulus Receptor Coordinator Effector ResponseFor example, consider
a man and a camel: Oh No!
What are the stimulus, receptor, coordinator, effector and response in this situation?
04/22/23Examples of reactionsExamples of reactionsStimulus Receptor
(i.e. the thing that detects the stimulus)
Effector (i.e. the thing that will do
the reaction)
Response (i.e. action
taken)
Bright light
Sour taste
Losing balance
Sit on a drawing pin
04/22/23Types of nerve cellTypes of nerve cellNucleus Muscle strands
(effector)Cell body
1) Motor neurone 2) Sensory neurone 3) Relay neurone
Impulse Impulse
Nerve cells (neurones) are elongated with branched endings to connect to many muscles
fibres.
Dendrites
04/22/23SynapsesSynapses
Neurones never ____ each other – there is a small gap between them called a _____. A signal is sent from one _______ to the next by a _______ transmitter across the synapse. These transmitters are then ________.
Words – chemical, synapse, neurone, touch, destroyed
04/22/23Conscious actionsConscious actionsA conscious action is one where the brain makes a considered response. Here’s what happens:
Stimulus Receptor Sensory Neurone Coordinator Motor Neurone Effector Response
1) Receptors in your skin detect a stimulus
3) Here another sensory neurone carries the signal to the brain
4) The brain decides to move away the hand
5) This impulse is sent by MOTOR NEURONES to the hand muscles (the effectors) via the spinal chord…
2) The impulse is carried by SENSORY NEURONES to the spinal chord
6) Which then moves the hand away
04/22/23Reflex actionsReflex actionsSometimes conscious action is too slow to prevent harm, e.g…
In situations like this the body bypasses the brain to produce a quicker response. Here’s how it works…
04/22/23Reflex actionsReflex actions
1. Receptor
2. Sensory neurone
3. Relay neurone in the spinal chord
4. Motor neurone
5. Effector
04/22/23VisionVision
“Binocular vision” “Monocular vision”
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Suspensory ligaments
Optic nerve
The EyeThe Eye
Retina
Pupil
Cornea
Ciliary musclesSuspensory ligaments
Optic nerve
Lens
Iris Sclera
04/22/23Seeing thingsSeeing things
Rays of light are refracted (bent) first by the cornea and then by the lens. They focus on the retina.
04/22/23Focussing on different distancesFocussing on different distancesFor distant objects the ciliary muscles
relax and the suspensory ligaments pull tight making the lens pull thin – the
light doesn’t bend as much.
For close objects the ciliary muscles
contract allowing the lens to go fat, thus bending the light
more.
04/22/23The Iris ReflexThe Iris Reflex
When the light is bright the radial muscles relax, the circular muscles contract and the pupil increases in size.
When the light is bright the radial muscles _____, the circular muscles _______ and the pupil ________ in size.
04/22/23Drugs Research ProjectDrugs Research ProjectExplain and give examples for the following:
1) Why do people use legal drugs?
2) What are the drawbacks of legal drugs?
3) Alchohol is a legal drug. What does it do to the human body?
4) Why do people use illegal drugs?
5) What are the drawbacks of illegal drugs? What can they cause?
6) Find out which drugs are in which classes
04/22/23DrugsDrugsDrug Effect on
nervesEffect on activities
Abnormal behaviour
causedCaffeine/ other stimulants
Barbiturates/ other sedatives
Paracetamol/ other painkillers
Speed up synapse transmissions
Reactions could become faster
Highly strung, leads to exhaustion
Slow down synapse transmissions
May make you drowsy, you shouldn’t drive
Highly addictive, make you irritable
Prevent synapse transmissions
May make you drowsy, you shouldn’t drive
Side effects include dizziness or itchiness
04/22/23SmokingSmokingCigarettes contain 3 harmful things:1. NICOTINE, which is an ___________ drug that raises the
heart beat, narrows the arteries and so causes ____ _____ _____. This leads to heart _________.
2. TAR, which coats the lining of the _______ making them less able to take in oxygen. It also contains carcinogens which cause ______________.
3. CARBON MONOXIDE, which is a _______ ____ which joins up with ____ blood cells making them incapable of transporting _____________ around the body. In pregnant women it can cause oxygen deprivation, leading to low birth ______.Words – high blood pressure, oxygen, red, addictive,
disease, poisonous gas, lungs, cancer, mass
04/22/23HomeostasisHomeostasisHomeostasis means “controlling internal conditions”:
Waste products that need to be removed + howCO2
Urea
Internal conditions that need controlling + howTemperature
Ion contentWater
contentBlood
glucose
Produced by respiration, removed via lungsProduced by liver breaking down amino acids,
removed by kidneys and transferred to bladder
Increased by shivering, lost by sweatingIncreased by eating, lost by sweating + urine
Increased by drinking, lost by sweating + urineIncreased and decreased by hormones
04/22/23Maintaining Body Maintaining Body TemperatureTemperature
Cold Hot
Vasodilation
Vasoconstriction
04/22/23HormonesHormonesHormones are “chemical messengers” produced by endocrine _____. They control the way in which parts of the body work and are transported to their target organs in the _______. Some examples...
• The pancreas produces _______• The adrenal gland produce ________• The pituitary gland produces FSH and LH• Testes produce __________• Ovaries produce progesterone The adrenal
glandWords – testosterone, glands, bloodstream, insulin, adrenaline
04/22/23Controlling Blood Sugar Controlling Blood Sugar levelslevelsWe need glucose in our bodies to help our cells to respire
and produce energy. What happens if we have too much glucose?
If blood sugar is too high the pancreas releases
insulin
The liver then converts glucose into insoluble
glycogen and is removed from the blood
04/22/23DiabetesDiabetesDiabetes is a ________ in which a person’s blood sugar (i.e. glucose) level may rise to a _______ level. This is because the ______ doesn’t produce enough _________.
Diabetes can be treated by __________ carefully or by injecting extra insulin when needed. Diabetics have to test their blood sugar level before they decide how much insulin to _______ themselves with.
Words – insulin, disease, inject, dangerous, eating, pancreas
04/22/23The Menstrual CycleThe Menstrual Cycle
Hormone concentration
Oestrogen – produced in the _______ and causes the lining of the uterus to ______
Progesterone – produced by the empty ________ and maintains the ______. If egg is _______ progesterone continues to be produced
Words – follicle, lining, ovaries, thicken, fertilised
Thickness of uterus lining
Day 0
Day 7
Day 14
Day 21
Day 28
04/22/23FertilityFertility
In normal circumstances natural hormones are responsible for releasing the egg and for thickening the lining of the womb. These hormones are produced by the pituitary gland in the brain and in the ovaries.
1) …stimulate the release of eggs
2) …inhibit the release of eggs
The amount of glucose in our blood is an example of a process controlled by hormones. Hormones are “chemical messengers”, produced by glands and tranposrted by blood. Another example of a process controlled by hormones is the menstrual cycle, where hormones can...
04/22/23Genes, Chromosomes and Genes, Chromosomes and DNADNA
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Some facts: - Made up of paired bases – A links with T and C links with G – to form a “double helix” - Contain instructions on what a cell does, how the organism should work etc - The instructions are in the form of a code - The code is made up from the four bases that hold the strands together - The bases represent the order in which amino acids are assembled to make proteins - Only some of the genes in each cell are “switched on” - DNA can be “mutated” by X-rays, UV, certain chemicals etc
How genes workHow genes work
04/22/23Sexual ReproductionSexual Reproduction
The human egg and sperm cell (“GAMETES”) contain 23 chromosomes each.
When fertilisation happens the gametes fuse together to make a single cell called a ZYGOTE. The zygote has 46 chromosomes (23 pairs) and contains information from each parent.
We have similar characteristics to our parents due to genetic information being passed down in genes through gametes:
04/22/23Sexual vs. Asexual Sexual vs. Asexual reproductionreproduction
Sexual reproduction:•2 parents are needed•Offspring will have “pairs” of chromosomes•This will cause genetic variation
Asexual reproduction:•Only 1 parent needed•Offspring are GENETICALLY IDENTICAL to parent (“clones”) “Snuppy” – the
first cloned dog (Aug 05)
04/22/23Boy or Girl?Boy or Girl?
X Y X
XX XYGirl Boy
“Allele”
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Father
Mother
Son
Daughter
Boy or Girl?Boy or Girl?
04/22/23Eye colourEye colourIn eye colour the brown eye allele is dominant, so we call it B, and the blue eye is recessive, so we call it b:
bbBB Bb
Homozygous brown-eyed
parent
Heterozygous brown-eyed
parent
Blue-eyed parent
What would the offspring have?
04/22/23Eye colourEye colourExample 1: A homozygous brown-eyed parent and a
blue-eyed parent:
Example 2: 2 heterozygous brown-
eyed parents
BB bbX Bb BbXParents:
Gametes:
Offspring: Bb Bb BbBb BB Bb bbbB
B B bb B bB b
(FOIL)
All offspring have brown eyes
25% chance of blue eyes
04/22/23Eye colourEye colourExample 3: A heterozygous brown-eyed father and a blue-eyed mother:
Bb
Bb Bb bbbb
bb
b bB b
Equal (50%) chance of being either brown eyed or blue eyed.
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B bbb
Another methodAnother methodExample 3: A heterozygous brown-eyed father and a blue-eyed mother:
B bb Bb bbb Bb bb
Father
Mother
04/22/23Example questionsExample questions1) In mice, white fur is dominant. What type of offspring would you expect from a cross between a heterozygous individual and one with grey fur? Explain your answer with a genetic diagram.
2) A homozygous long-tailed cat is crossed with a homozygous short-tailed cat and produces a litter of 9 long-tailed kittens. Show the probable offspring which would be produced if two of these kittens were mated and describe the characteristics of the offspring (hint: work out the kitten’s genotype first).
04/22/23Inherited diseasesInherited diseases1) Cystic fibrosis – a disease that causes thick and sticky mucus to coat the lungs, gut and pancreas. It’s caused by recessive alleles:
2) Huntingdon's disease – a disease of the nervous system that causes shaking and eventually dementia. It’s caused by a dominant allele:
3) Sickle cell anaemia – a disease that alters the shape of red blood cells, thereby reducing their oxygen capacity, causing weakness and anaemia. It’s caused by recessive alleles:
Ff FfX
Cc ccX
Ss SsX
04/22/23Key wordsKey wordsGamete
Zygote
Allele
Dominant
Recessive
Homozygous
Heterozygous
•This allele determines the development of a characteristic•This is formed when an egg is fertilised by a sperm•This allele will determine a characteristic only if there are no dominant ones•This word refers to a pair of chromosomes being made of two different alleles of a gene•An egg or a sperm are called this•This word refers to a pair of chromosomes being made of two of the same alleles of a gene•An alternative form of a gene