MEDICAL TECHNOLOGY – BIONICS

1. Increases in scientific understanding and technological advances have broadened options for maintaining humans as functioning organisms.

Identify parts of the body and the biomaterials and biomedical devices that can be used to replace damaged or diseased body parts including

Biocompatibility: The ability of a material to function within an organism without the material being damaged or causing damage.

Biomaterials: Substances that can be safely placed in contact with living tissue without the tissues reacting adversely with it or rejecting it.

Example of Biomaterials: Metals (Titanium, Plastics (Teflon, Dacron), Ceramics, Biological Tissue.

Biomedical device: An implant or device made from biomaterials, which can be placed in the body and will function there.

Prosthesis: An artificial replacement for a missing part of the body.

Pins, screws and plates These are used to repair bone fractures. They are all made from metallic alloys and

covered by titanium. The pin is a versatile implant used for the fixation of bone fragments and is used when

the fracture is in a place where it is difficult to use a plate. Pins are also used when it is difficult to obtain adequate stability of the bone fracture

by any other means. Screws are some of the most widely used devices for repairing fractures. They are

used to fix bone plates to bones. Bone plates are also used to repair bone fractures. They are designed to be very strong

and absorb the large stress forces generated when the bone moves. It is also important that the bone plate be fixed to the bone with the use of screws.

Artificial Joints These replace joints that have been largely destroyed by degenerative diseases such as

arthritis or damaged badly in an accident. Can include knee, hip, shoulder, wrist, elbow joints Artificial hip joints are often made from a stainless steel-polyethylene or cobalt-

chromium alloy-polyethylene combination. Other materials that can be used are:– titanium– titanium-aluminium-vanadium alloy– ultra-high molecular weight polyethylene– metal-pyrolytic carbon coating– metal-bioglass coating– composites made from poly-methyl methacrylate (PMMA) and carbon fibre– porous stainless steel. Artificial knee joints are known to sink into the lower bone of the leg, causing

crushing of the trabecular bone. To combat this problem, knee joints are now made

from a layer of ultra-high molecular weight polyethylene (UHMW polyethylene) on a metal base.

Other joint replacements, such as fingers and ankles, have not been as successful, because of the complexity of movement of these joints.

Pacemakers Pacemakers are used to correct arrhythmias, that is, when the heart beats too fast, too

slowly or irregularly. A pacemaker is a battery-operated device designed to stimulate contraction of the heart at a certain rate. Some are internal (surgically implanted) and others are external. Pacemakers are connected to a small electrode, which is placed near the wall of the heart. Small electrical charges travel through a wire to the electrode, stimulating the heart to contract.

The casing of a pacemaker can be made of stainless steel or titanium. The electrodes are made from platinum or platinum-iridium alloy. Silicon rubber, polypropylene or epoxy can be used to seal parts of the pacemaker.

Artificial Valves Artificial valves can be used to replace damaged valves in the body that are no longer

functioning to keep blood flowing in one direction only. Early artificial valves in the 1960s were made from flexible leaflets but could not

withstand the fatigue for periods longer than about three years. Most artificial valves have a fabric ring surrounding them, which allows a surgeon to

sew the device into place during implantation. Where appropriate, artificial valves are constructed from collagen-rich materials, such

as pericardial tissues which have been obtained from pigs or cows and treated (to denature any animal proteins), to minimise the risk of rejection by the human body. Other materials used are cobalt-chromium alloys, low-temperature carbon and titanium alloy with pyrolytic carbon discs or balls.

Crowns and dentures A crown is a tooth cap that is placed over an artificial or natural root system. Crowns have traditionally been constructed from ceramic materials, which have

relatively low strength. The development of metal-ceramic crowns has led to an increase in strength.

Dentures (false teeth) are generally made from acrylic, so it’s easy to produce. Dentures present problems because:– they are not particularly stable– they do not always look natural– they allow the jawbone to absorb substances.

Lenses

Artificial lenses restore function in the eye where a cataract has caused the previous lens to go cloudy.

Artificial lens ix commonly made from PMMA, silicone rubber, copolymer blends; nylon; Dacron; or polypropylene. Tiny platinum, titanium or gold loops are sometimes used to hold lenses in place.

Ultrasonic waves are used to pulverise the inner part of the natural lens, which is then sucked out. An artificial lens, which measures about six millimetres in diameter and resembles a hard contact lens, is then inserted into the empty space.

There are 2 types of implants available: non-foldable and foldable. Nonfoldable lenses are made of PMMA, a hard-plastic material. Foldable lenses are made of either silicone or acrylic.

Prosthetic Limbs These are artificial limbs that are commonly used to replace entire limbs, or part limbs

on amputees. Materials that are sometimes used include silicone or silicone matrix (for liners), and

titanium, aluminium, stainless steel or carbon fibre composites. Modern prosthetic limbs often incorporate electronics mechanisms that are complex.

Cochlear Implants A cochlear implant is an artificial hearing device that can replace a damaged cochlea.

It is designed to stimulate nerves inside the inner ear, that produce a hearing sensation. The cochlear implant works by converting sound into electrical impulses, which can be used to stimulate the auditory nerves, sending a signal to the brain, which creates a hearing sensation.

Cochlear implants generally consist of two main components:– a headset with a 22-channel stimulator in a titanium capsule, with platinum electrodes

which are implanted inside the skull behind the ear close to nerves.– a pocket speech processor, which breaks down speech into its various components

before transmitting it back to the stimulator.

Biomedical device/implant

What it’s used for Biomaterials used Example

Pins, screws and plates

Replace bones and repair damaged joints.

Titanium, titanium-coated stainless steel.

Titanium plate inserted into damaged skull to protect brain.

Artificial joints Replace damaged joints to allow movement.

Metals, polyethylene. Knee, wrist, shoulder, hip and elbow joints.

Pacemaker Send electrical signals to the heart to maintain a regular beat.

Titanium, polyurethane, silicon semiconductors.

Pacemaker.

Artificial valves Replace damaged or faulty valves.

May be from a human donor or pig’s valves. Mechanical valves use stainless steel and strong polyester.

Artificial valve.

Crowns and dentures

Used to replace damaged or lost teeth.

Metal, porcelain, plastic and ceramics.

Artificial teeth.

Lenses Repair and aid eyesight. Silicone, Glass. Contact lenses.

Prosthetic limbs Replace damaged or unusable limbs.

Metals (titanium, alloy), polymer.

Arms, legs.

Cochlea implants Artificial hearing device that helps with hearing problems.

Bionic ear.

Material Example of how the material is used

Properties that make material biocompatible

Metals Aiding bone healing, replacement joints.

Titanium is biocompatible and doesn’t react with the body, stainless steel is strong and cheap but can rust, and cobalt alloys are expensive but last longer.

Ceramics Dentistry, joint and bone segment replacement, temporary bone repair.

Strong, non-flexible, resist corrosion, low density, and biocompatible

Plastics Repair and enhance the human body.

Can be created to suit almost any application, needs to be strong, and suited to body temp.

Polyethylene Replacement parts e.g. hips and knees

Dense. Resistant to abrasion and cutting, self-lubricating.

Silicone Breast implant replace cartilage in small joints.

Stable, heat resistant, not damaged by light, long life span.

Gather and process information from secondary sources to trace the historical development of one of the following implants:

- Artificial Valves

2. The regular beating of the heart and continuity of the flow of blood through the heart and around the body is needed to maintain good health

The circulatory system consists of the heart and blood vessels, which maintain a continuous flow of blood through the body.

The heart is a muscle. Its function is to pump blood around the body.The blood carries oxygen, nutrients and other chemicals such as hormones to body cells and carries waste

products such as carbon dioxide, to appropriate organs for removal.

Explain the relationship between the structure and function of the following parts of the heart

Valves Valves are structures present in the heart and in veins that allow blood to flow in one direction only. Valves consist of flaps of tissue that are oriented to allow this unidirectional flow. Flow in the opposite direction will cause them to close.

Atria The function of the atria in the heart is to receive blood from the veins before passing

it on to the ventricle. About 80% of the blood received in the atria flows into the ventricles while the heart

is relaxed. The first beat of a heartbeat cycle is the contraction of the atria pushing the remaining 20% of the blood into the ventricles.

The atrium has thin elastic walls, as only a small amount of heart muscle is required to push the 20% of remaining blood into the ventricle.

Ventricles The ventricles receive blood from the atrium. The function of the ventricles is to

pump the blood either to the lungs for re-oxygenation (right ventricle) or to the body for distribution to cells (left ventricle).

Because the ventricles must pump the full component of blood received (unlike the atria), the walls of the ventricle are much thicker and much more muscular than those of the atria.

Major arteries and veins Arteries carry blood away from the heart and veins carry blood back towards the

heart. There are two major veins, one bringing blood back to the heart from the upper and

one bringing it from the lower body. The walls of the major arteries and veins are composed of four layers:- an inner layer of connective tissue- a thick layer of elastic fibres surrounding the connective tissue, allowing the vessel to

change size depending on blood flow- a layer of smooth muscle, ensuring that the vessel does not over-expand- an outer layer of connective fibres, giving the vessels elasticity and strength. Veins do not have to withstand the high pulsing pressures that arteries do, because the

intricate capillary network absorbs much of the force of the heartbeat. Veins, therefore, have much thinner layers of muscle and elastic fibre.

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

right atrium

lungs

oxyginated blood

left atrium

left ventricle

arteries

body

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.

INFERIOR VENA CAVA: Large vein that carries deoxygenated blood from the lower half of the body to the right atrium of the heart.SUPERIOR VENA CAVA: Large vein that carries deoxygenated blood from the upper half of the body to the right atrium of the heart.

Explain that specialised tissues in the heart produce an electrical signal that stimulates rhythmic contractions of the cardiac muscle

The heart has its own natural pacemaker, a small mass of specialised cells in the top of the right atrium. This mass of specialised cells is called the sino-atrial (S.A.) node or sinus node.

The chambers of the heart will contract when an electrical impulse moves across them.

The sinus node sends electrical signals directly to the atria, stimulating them to pump, before sending electrical signals through other nerve connections to the ventricles.

Discuss the problems that can result from interruptions to the normal rhythm of the heart

Arrhythmia refers to the disturbance of the normal heart rhythm. An arrhythmia is any deviation from or disturbance of the normal heart rhythm. The basic rhythm of the heart is a tightly regulated occurrence ensuring maximum

efficiency and optimal performance. Heart rate is a dynamic occurrence that changes according to the metabolic needs of

the body resulting from the factors such as changing exercise rates.

Heart Murmur If the flow of blood is obstructed, the flow becomes turbulent (heard on a

stethoscope). 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.

Common in children with thin heart muscles walls, and is non problematic. Occasionally indicates faulty valves and a back-flow of blood into the wrong

chamber.

Ischaemia and Fibrillation Ischaemic → Lack of oxygen 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.

Causes the heart to pump rapidly to try to get more oxygen to the heart. Heart muscle contracts erratically - called fibrillations. May result in heart attack and death.

Arrhythmias Arrhythmias (or Dysrhythmias) are problems that affect the electrical system of the

heart muscle, producing irregular heart rhythms. Irregular rhythms can cause the heart to pump blood less effectively and this reduces

the supply of oxygen to the body and reduces CO2 removal.

Tachycardia 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

Bradycardia 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

Palpitations – Irregular Heartbeat

Heart Attack – If one of the coronary arteries is blocked by a blood clot then part of the heart muscle will die-causing severe chest pain and cardiac arrest.

Cardiac Arrest - The heart stops pumping effectively- most commonly the muscles of the ventricles start beating fast and irregularly, without pumping blood.

Damage to the S.A. Node If the S.A. node is faulty, or the electrical signals sent by the S. A node are blocked,

the heart muscle contracts uncontrollably. Ventricles beat at wrong rate. Decreases in heart pump efficiency. Artificial Pacemakers can help fix this by emitting an electrical impulse at regular

intervals.

Identify that a pacemaker will produce a regular electrical impulse

A cardiac pacemaker is an electronic device, usually implanted in the upper chest, beneath the collarbone.

A cardiac pacemaker is used to correct arrhythmias initiating from conduction problems with the natural pacemaker, the sinus node.

The stimulator of the pacemaker produces an electrical current, which is transmitted down conducting electrodes. The electrodes are positioned near the side of the atrium.

The pacemaker delivers an exact amount of electrical current to the heart at varying rates.

Identify the types of materials used to make pacemakers and the properties that make these suitable for implanting in the body

A pacemaker is made up of a stimulator and electrodes the stimulator is fully sealed in a titanium casing (non-corrosive and non-reactive in

the body) electrode outlets:- are protected by a polypropylene cuff (prevents loss of electrical signal)- insulated with silicone or polyurethane rubber, except for the tips which are

embedded into the cardiac wall

- tip of electrode is usually made of platinum-10% iridium alloy (non-corrosive, non-reactive and possesses reasonable mechanical strength)

strong electromagnetic fields can disrupt the programming of pacemakers, so modern pacemakers are shielded from electromagnetic forces and also have a backup mode that takes over if the main circuit is disrupted.

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.

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

A defective heart valve may result in the valve failing to open fully. If a heart valve can’t open completely, blood flow is reduced, preventing parts of the

body from receiving enough oxygen. A reduced oxygen supply to the body is the immediate consequence of faulty valve,

causing breathlessness, fainting and unconsciousness.

A defective heart valve may result in the valve failing to close fully. A valve that is not able to close completely leads to regurgitation, which also reduces

the supply of oxygen to the body. Diminished oxygen supply is the immediate consequence of faulty valves. The more extensive the damage to the valve, the less efficient the heart action and the

greater the strain placed on the heart.

If a heart valve is not functioning properly, a certain amount of blood will flow back into the chambers of the heart. This means that the usual amount of blood required by the body to function is not being sent at the normal rate therefore, the heart has to pump at a greater speed to keep up with the needs of the body. The more damaged a heart valves, the harder the heart muscle has to work (it is put under more strain).

Describe the properties of materials such as Teflon/pyrolytic carbon that make them versatile materials for making artificial body parts, including heart valves

Teflon Teflon is used in the manufacture of a wide array of artificial body parts, including blood vessels, hip sockets and soft tissue prostheses, such as ear and nose replacements.

- it is flexible- it is easy to fabricate- it has a high density- it has a low coefficient of friction

- it is one of a few polymers that can be dry sterilised, and therefore made aseptic with minimal contact with other factors.

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.

Pyrolytic Carbon Is used as a coating in the manufacture of artificial body parts It has excellent compatibility with living tissues and therefore is less likely to be

rejected by the body. It possesses greater elasticity than graphite, an alternative material. Its compressive strength is about four times the strength of graphite. It is not prone to absorption or swelling in the body, and therefore may be used as a

coating on the ball or disc in artificial heart valves. Earlier artificial heart valves that used silicone swelled up and caused blockages in the flow of blood around the heart.

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

The build-up of plaque on the walls of arteries and veins is termed atherosclerosis. The fatty deposits can harden into plaque, which then narrows the arteries and reduces

their elasticity. If the artery becomes blocked by a blood clot, a heart attack or stroke may occur.

A heart that has narrow or hardened arteries is not able to function as effectively as a pump because the blood flow is restricted. If areas of the heart are denied oxygen, pain called angina or even heart attack may occur.

These attacks may result in scar tissue in the muscle walls of the heart that weakens it. Build-up of plaque also causes the walls of the artery or vein to become weakened, to

bulge or split.

A fat deposit can build up on these walls when fat or cholesterol is carried by the bodies blood

The smooth walls of these arteries and veins is then broken down leaving exposed rough, fibrous tissue

The blood platelets can adhere to this rough surface causing a blood clot The common results of blood clots are a raised blood pressure leading to aneurysms

(bulging and weakening of the blood vessel wall) or obstructions such as embolisms (mobile blood clot) or a thrombosis (a localized blood clot).

Atherosclerosis of the coronary artery can lead to a fatal heart attack

Discuss ways in which plaque could be eliminated or altered to ease blood flow

Medication To orally take thrombolytic (clot-dissolving) agents, such as tissue plasminogen

activator. Modern medications can lower a person’s blood pressure and thus reduce the strain on

the heart as a pump, widen the blood vessels so that blood flow is not restricted, or slow down the heart rate

Angioplasty Laser angioplasty uses a laser beam to remove plaque from blood vessels. A catheter

containing the laser is pushed under the skin Balloon angioplasty is used to improve blood flow by widening the artery. A small

cut is made in 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 diameter is widened.

Coronary by-pass surgery This is where a section of healthy artery, usually from the leg is taken and placed

around the artery of the heart to bypass the blockage. This provides a detour for the blood around the damaged vessel.

Gather, identify data sources, plan, choose equipment or resources for, perform a first-hand investigation and analyse information about changes in the heartbeat rate before and after physical activity

Aim: To determine how exercise affects the pulse rate.Hypothesis: Exercising does affect the pulse rate and it will increase the amount of pumps because when you exercise, your body has to pump more blood.Materials: Timer/stopwatch, the method of exercise (e.g. star jumps, dancing), pen and piece of paper.Method:1. Test your heart rate before exercising for 1 minute.2. Write down the results.3. Do an exercise. Whether it will be star jumps, running around the block or dancing. 4. After exercise, test your heart rate for 1 minute.5. Write down the results.6. Repeat Steps 1-5 for Trials 2 and 3.

Results:Discussion: Conclusion: The results show that the hypothesis was correct, and it estimated that my heart rate would take about 4-6 minutes to return back to normal.

Plan and perform an investigation to identify individual aspects that comprise the heartbeat.

A stethoscope is a medical instrument for listening to the action of someone's heart or breathing, typically having a small disc-shaped resonator that is placed against the chest, and two tubes connected to earpieces.When conducting this experiment:

Hear two thumps. Notice the closing of the valves. “Lub” – AB valve closing. “Dub” – Pulmonary/Aortic valves closing.

Identify data sources, gather, process and analyse information to outline the historical development of pacemakers and use available evidence to identify types of technological advances that have made their development possible.

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 onto a wall socket.

Some of the technological advances that led to the development of the modern-day pacemaker include:

Devices which reduced the amount of voltage and increased the length of time in the electronic pacing.

Pacemakers with leads attached directly to the out wall of the heart. Portable devices, which used a battery as the power source. An Australian physician

Mark Lidwill, together with a physicist Edgar Booth, are credited with inventing the first portable pacemaking unit, demonstrated in 1931.

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 pacemaker into a vein and threading the lead into the heart chamber.

Development of smaller pacemaker units. Improvement 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, reprogrammed and monitored from outside the patient’s body. The most common pacemaker monitor’s the heart’s activity and takes control when the heart rate falls below a programmed minimum – usually 60 beats per minute.

Construct a simple model to demonstrate the function of valves in the heart

Gather, process and analyse information to outline areas of current research in heart transplants and/or artificial hearts and their impact on society.

Heart transplants

Question 1: Define heart transplants.A heart transplant is surgery to remove a person's diseased heart and replace it with a healthy heart from a deceased donor. Most heart transplants are done on patients who have end-stage heart failure. Heart failure is a condition in which the heart is damaged or weak.

Question 2: Outline the use of heart transplants.Your diseased heart is removed, and the donor heart is stitched in place. The heart-lung machine is then disconnected. Blood flows through the transplanted heart, which takes over supplying your body with blood and oxygen.

Question 3: Describe current research about heart transplants.The preservation of donor organs and clinical trials of new therapies to improve patient outcomes after heart transplantation.

Question 4: Assess the impacts of heart transplants on society. ADVANTAGES DISADVANTAGES

May be the only solution to save a person’s life.

Higher risk on operation

Reduces reliance on continual medicine Higher costsProvides the person a better quality of life after transplants

Limited supplies of suitable donors

The judgement of heart transplants is that based allocation on a judgement of whether one's condition was self-inflicted is simply not possible.

The development of medical procedures that allow heart transplants to take place has several impacts in society:

People with heart disease will have an extended lifespan - this contributes to an aging population.

People awaiting heart transplants can wait years for a transplant due to the lack of doors. This can have significant impact on the recipient, caregiver and hospitals which attempt to keep the person alive after their own heart ceases to function.

Heart transplant recipients experience emotional distress at being called into hospital to receive a transplant and the donor heart is found to be damaged and not viable for transplantation.

Ethical, moral and religious implications argue for and against replacing body parts to extend the lives of people who would otherwise die.

Patients may increase their susceptibility to other life-threatening diseases as a result of a heart transplant by taking immune suppressing drugs which minimise the rejection of transplanted tissue.

Upon obtaining a driver’s licence, people must choose to be an organ donor or not. Families of people who dies suddenly are faced with organ donation decisions as they

are coming to grips with the tragedy. Organs are often removed while the body is still functioning and to optimise the

recipient’s chances of survival. Removal of organs such as a beating heart from a brain-dead person has emotional

impacts on nurses and medical staff as the person is technically still alive.Gather information from secondary sources on techniques used, including angioplasty, to ease blood flow to and from the heart and in blood vessels, when there has been a build-up of plaque

Bypass surgery – this involves taking a vein from the patient’s leg and using it to construct a new pathway for blood to flow around the blocked vessels.

Replacing the blocked blood vessel with an artificial vessel – a woven plastic artificial graft is soaked in blood and then sewn in place. Body cells (fibroblasts) invade the artificial structure and eventually it becomes ‘normal’ tissue.

Angioplasty – a technique for easing blood flow. 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.

Balloon angioplasty is used to improve blood flow by widening the artery. A small cut is made in 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 small 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.

Angioplasty is a surgical technique used to improve blood flow. A stent is being inserted into an artery. A catheter is inserted into the artery with a rotating blade or laser on the end. This removes part of the plaque built up inside the walls of the artery. The catheter then inserts the stent to hold the artery open and improve blood flow. The catheter is removed when the stent is in place.

This technique might be necessary because the plaque as built up inside artery walls reducing the flow of blood through the artery. This is affecting the person by causing breathlessness, inability to exercise effectively and possibly angina. If flow isn’t improved, the person could have a heart attack.

The decision to use a particular technique is based to some extent on the degree to which the blood vessel(s) is blocked.

Process information to identify different types and functions of artificial valves in the heart

Artificial valves are more durable than biological valves but need anti-coagulant to prevent blood clots forming around the implant.

The bi-leaflet 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. Biological valves include valves from a human donor 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 is seven to ten years before the tissue degenerates. The use of pig donor tissue for human transplants is currently being reconsidered following concerns that diseases can be transferred to humans by implanting pig tissue.

Replacement heart valves may be taken from an animal, e.g. a pig, or manufactured from synthetic materials.

The requirements of an artificial heart valve that allow it to function effectively include:

- Be able to open and close at a regular rate for many years.

- Be smooth so there’s no turbulence or clotting as the blood flows through it.- Close firmly so that it doesn’t allow any blood to leak backwards.- Be biocompatible so the body doesn’t reject it.- Be sterile so the person doesn’t become infected.

The TWO types of manufactured heart valves are:1. Ball-in-cage valve: A ball inside a metal cage-like container. The blood pushes the ball out of the way as it flows through. If the blood tries to flow backwards, it pushes the ball against the ring, sealing the space.2. Bi-leaflet valve: Two semicircular discs, usually made of carbon, which open to allow the flow of blood and then close to prevents its back-flow. These cause less blood turbulence than the ball- in-cage valves.

3. The wide range of movements, continual absorption of shocks and diseases make the skeletal system vulnerable to damage, but new technologies are allowing the replacement of some damaged structures

Identify the role of the skeletal system particularly in relation to maintaining an upright stance and protecting vital organs

Support - Our bones provide the internal framework to support all our organs, the S-shaped structure of our backbone makes it possible for us to stand upright using our leg bones as pillars.

Protection - Our bones protect the soft organs of our bodies from damage. The bones of the skull protect the brain, the rib cage protects the heart and lungs, and the vertebrae of our backbone protect the spinal nerve.

Movement - The muscles attached to our bones provide our bodies with movement. They contract and relax to help us walk, run and jump and must be firmly anchored to our skeleton.

Storage - Bones can be spongy or compact in structure and hold inside them minerals like calcium and phosphorus. Calcium is important for contracting muscles, sending nervous messages and makes bones strong and hard.

Production of blood cells - Bone marrow produces red blood cells, some white blood cells and some platelets.

Skeletal System: The framework of the body, consisting of bones and other connective tissues, which protects and supports the body tissues and internal organs.Bones: A structure composing the skeleton of a vertebrate.Tendons: A flexible but inelastic cord of strong fibrous collagen tissue attaching a muscle to a boneCartilage: A firm, flexible connective tissue.Ligaments: A short band of tough, flexible fibrous connective tissue which connects two bones or cartilages or holds together a joint.

Describe the different types of synovial joints as (and identify their location):A synovial joint is a freely moving joint because there is a space between the bones forming the joint. A synovial membrane surrounds the joint, secreting synovial fluid into the space to provide lubrication and allow easy movement.

Ball and Socket Joints: which occur where a rounded head (ball) fits into a cup-shaped socket on another bone. These allow side-to-side, back-and-forth and rotational movements. Examples include the hip and shoulder joints.

Hinge Joints: Which occur where a bone with a concave shape meets a bone with a convex shape, permitting only back and forth movement, such as bending and straightening. Examples include the knee, knuckle and elbow joints.

Double Hinge Joints: Which are found where two saddle-shaped surfaces join at right angles to each other. The joint allows side-to-side and back-to-forth movement, but no rotation. An example is the double hinge joint between the carpal and metacarpal bones of the thumb, which allows the thumb to be placed across the palm of the hand. A double hinge joint is also known as a saddle joint.

Sliding Joints: Which are found where two bones with flat surfaces slide on each other. Their movement is restricted by a number of ligaments. Sliding joints permit side-to-side and back-to-forth movement. Examples include those between the ribs and thoracic vertebrate, between the carpels and between the tarsals.

Pivot Joints: Which occur where a cylindrical bony point rotates within a ring composed of bone and ligament. Rotational movement is the main movement allowed. An example is the radioulnar joint just below the elbow, which allows us to rotate our forearm inwards and outwards.

Type of synovial joint Properties Location of jointBall and socket -a well-rounded head fits into

a ball-shaped socket on another bone-allowing side-to-side, back-and-forth and rotational movement

-hip -shoulder

Hinge -occur when a bone with a concave shape meets a bone with a convex shape-allowing only back and forth movement (e.g. bending and straightening)

- knee-knuckle-elbow

Double hinge -occur where two saddle-shaped surfaces join at right angles to each other-allowing side-to-side and back-and-forth movement but no rotation-also known as a saddle joint

-the base of the thumb (only saddle joint in the entire body)

Sliding -occur where two bones with flat surfaces slide on each other-movement is restricted by numerous ligaments-allow side-to-side and back-and-forth movement

-between the ribs and thoracic vertebrate-tarsal bones in the feet

Pivot -occur where a cylindrical bony point rotates within a ring composed of bone and ligament-allowing rotational movement

-radioulnar joint just below the elbow, allowing inwards and outwards movement of the forearm-neck-wrist

Describe the role of cartilage and synovial fluid in the operation of joints

Cartilage lines the ends of bones and reduces friction. This allows for smoother movement. If the cartilage is damaged or becomes worn, movement is less smooth and can cause pain. The synovial membrane encloses synovial joints. This produces synovial fluid to lubricate the joint and acts as a cushion, ensuring that the bones keep apart. Damage to the synovial membrane can cause excessive secretion of the fluid, which results in swelling of the joint.

The porous, sponge-like part of a bone is less dense and therefore has lower shock-absorbing ability than the shaft of long bones (such as the arms and legs), which are designed for maximum strength and shock- absorbing under stress or impact.

Identify the properties of silicone that make it suitable for use in bionics

It has a high permeability to oxygen, which means minimal obstruction to the distribution of oxygen around the body.

Resistant to acids, ozone and UV light Inert, meaning it doesn’t react with the human body’s chemistry and so can be used in

implants, medicines and food processing Able to maintain its flexibility and elasticity in high or low heats, so it can be used for

things like oven door seals or freezer door seals Does not dissolve or react with water and is water-resistant Low flammability

Explain why silicone joints would be suitable substitutes for small joints in the fingers and toes that bear little force

Silicone joints would be suitable substitutes for small joints in the fingers and toes because they can be made as strong and as flexible as natural joints. They are biocompatible, as they allow the flow of oxygen and do not react with living tissue. They would last a long time, as they do not dissolve in watery solutions and are not rejected by living tissue.

Describe the properties that make ultrahigh molecular weight polyethylene (UHMWPE) suitable alternative to cartilage surrounding a ball and socket joint in terms of its:

Biocompatibility with surrounding tissue - It possesses a similar density to living tissue and tends not to cause properties in the body.

Low Friction – It has a low friction coefficient

Durability It has no known solvent at mild temperatures It has very high creep resistance (creep resistance - tendency to deform when under

constant strength).

Extras High tensile strength High elasticity High hardness

Explain why artificial joints have the articulating ends covered in polyethylene

A natural synovial joint has cartilage which cushions the end of the joint and provides ease of movement when combined with synovial fluid. It is important that when an artificial joint is placed in the body it replicates the joint’s natural characteristics. Polyethylene is used to coat the end of artificial joints because it has:

a similar density to the body’s natural tissue it is elastic it has a low coefficient of friction it has high creep resistance

Recently, ultra-high molecular weight polyethylene (UHMWPE) has been developed, which exhibits superior characteristics under stress.

Describe the properties of the materials, including ‘superalloy’ that make a ball and stem for the bone components of a large joint including:

Superalloys are made from metals. They combine the ‘superior’ properties of metals such as iron, cobalt or nickel with molybdenum, chromium and titanium. The resulting properties include, high strength, low weight, good compatibility with body tissue and inertness. E.g. Cobalt, chromium and molybdenum alloy used in biomaterials is non-magnetic with high strength, corrosion/wear resistance. Superalloy materials are used to make a ball and stem for the bone components of a large joint.

Identify that artificial implants can be either cemented or uncemented into place

Cemented Implants Used for joints in hip or knee replacements Relies on a fixing agent to secure the superalloy structure into place After being placed in the joint the cement is then exposed to a catalyst causing the

‘glue’ to react which then forms long polymer chains. These chains interweave about the bone tissue and around the surface of the artificial

stem, forming a tight, solid bond. The ‘glue’ used in these cases is a compound called methyl methacrylate. The

metallic artificial stem is inserted and cemented into the femur of a hip replacement. The cement may be pre-treated by centrifuging to reduce porosity. It may also be mixed with an antibiotic to help stop infection.

Uncemented Implants Uncemented joints have microscopic pores which allow the bone of the normal femur

to grow into and around the artificial stem. Once the body’s own bone and scar tissue interweave with the implant, it will be held securely in place.

The uncemented hip replacement is considered to last longer than a cemented one and is therefore more commonly used in younger patients.

It will not be recommended to patients who have had a fractured femur or if the bone stock is of poor quality as sufficient growth of bone tissue into the implant may not occur.

Describe the properties of the cement that is used in implants and discuss how an uncemented implant forms a bond with bone

The cement used in a cemented implant serves many purposes. These include the following: It allows the initial fixation of the implant to the bone. it acts as a shock absorber for the joint, as it is a viscoelastic polymer. It helps to spread the load more evenly over a large area and reduces the stress

concentrated on the bone by the prosthesis. In contrast, a cement-free implant is coated with a porous layer, which comes into contact with the bone, placing less pressure on the bone (which sometimes leads to bone reabsorption and therefore loosening). The porous layer of cement-free implants allows the bone to grow into the implant, creating a dynamic interface of bone and implant.

Perform a first-hand investigation to remove calcium compounds from chicken bones to examine the flexible nature of bones

Aim: To observe how the flexibility of bone changes as the calcium content is changed.Hypothesis: I predict that the chicken in white vinegar solution will become flexible and soft, while the more calcium it has, the more solid it will become after a couple of days.Materials: 2 chicken wing bones, 2x 100ml measuring cylinder, 2x 250ml beaker, 100ml white vinegar, 100ml plain water, Glad Wrap and 2x elastic bands.Method:1. Collect all equipment.2. Place an 8cm chicken bone in a beaker each.3. Using a measuring cylinder, fill 100ml of plain water and pour it into a beaker.4. Repeat Step 3 but fill 100ml of white vinegar and pour it into another beaker.5. Put on Glad Wrap on all beakers securing with an elastic band on each. Leave for 2 days and note the changes.

Results

Discussion

Conclusion: The results show that the hypothesis was correct as the chicken bone placed in white vinegar solution has become slightly bendy as it lost calcium.

Perform an investigation to examine the relationship between cartilage, muscle, tendon and bone in an animal limb.

Example: Chicken wingThe table shows the properties that a Year 12 student has observed for each of the following components of a chicken wing.

Perform an investigation to demonstrate the different types of joints and the range of movements they allow.

The following table shows some joints they would have observed, identified their type and compared their movement.

Process secondary information to compare the shock absorbing abilities of different parts of bones

Aim: To examine a bone and compare the shock absorbing abilities of different parts of the bone. Materials: Large bone, sawn open lengthwise.Method:1. Observe the bone provided by your teacher.2. Draw a neat, labelled diagram of the bone using a pencil.Results:

Discussion: Cartilage is considered to be the most elastic. The following parts of a bone in decreasing order of shock absorbing ability are: cartilage, spongy bone, compact bone and bone marrow.Conclusion: A bone was examined and the different parts abilities to absorb shocks were compared.

A bone is made up of two types of tissue: spongy bone and compact bone. Compact bone provides protection and support, and forms a hard, thin layer over the inner spongy bone. It therefore has little role in shock absorption. Spongy bone is very porous and contains bone marrow. Compact bone is must denser, with a porosity ranging between 5% and 10%. Spongy bone is soft and spongy and therefore more open to shock absorption. It distributes and dissipates the energy transferred to it by compact bone.

Plan choose equipment or resources for and perform a first-hand investigation to demonstrate properties of silicone such as acid resistance, flexibility and imperviousness to water that make it suitable for use in bionics.

Aim: To demonstrate properties of silicone such as acid resistance, flexibility and imperviousness to water.Hypothesis: The silicon will have acid resistance and will also be impervious to water. Materials:

Method:1. Collect all equipment.2. Weigh in a piece of silicone each and record results.3. Add the 20mL of acid in a test tube and place it into the test tube holder.4. Repeat Step 4 but this time add 20mL of water into another test tube and place it into the testtube holder.5.Leave for 10 minutes and observe changes.

Results:

*If there was no change in weight, there has been no chemical reaction with the acid.^If there was no change in weight, water has not been absorbed by the silicon – i.e. the silicon is impervious to water.

Discussion

Conclusion: Silicon has a number of properties that make it suitable for use in implants. It is acid resistant and impervious to water. Analyse secondary information to compare the strength of UHMWPE and ‘superalloy’ metal

Properties of superalloys include:- An extremely high impact resistance- Resistance to wear and abrasion- A very low coefficient of friction- Very good chemical resistance- Excellent low-temperature properties

Properties if UHMWPE include:- High-abrasion and impact resistance- Low slip/stick friction- High stress-crack and chemical resistance- Contains no other additives

4. Life support systems can be used to sustain life during operations or while the body repairs itself

Describe the structures of the respiratory system and identify their function including: The exchange of oxygen and carbon dioxide gases between the blood and the air takes place in the lungs. Air is forced into the lungs through a process called inhalation. Air is forced out of the lungs through a process called exhalation.

Trachea long tube connecting the pharynx, mouth and nasal cavities to the bronchi it is supported from collapse by rings of cartilage during inhaling, when the pressure

in the lungs is negative

Bronchi The bronchi connect the trachea to the lungs. There are two bronchi, one going to each lung, each having a similar structure to the

trachea, with cartilage rings for support during times of negative pressure.

Alveoli The bronchi divide into smaller bronchioles, which eventually terminate in the

gaseous exchange zone of the lung, the alveoli. There may be as many as 100 million alveoli in each lung. The walls of the alveoli are thin and moist, allowing gases to dissolve and move easily

from inside the alveoli to the blood capillaries that surround the alveoli.

Capillary network around the alveoli The capillaries are fine blood vessels that transport high-oxygen blood from the lungs

to the pulmonary vein (to be taken to the heart and pumped to the body) and low-oxygen blood from the pulmonary artery to the lungs for exhalation.

The intricate capillaries surround each alveolus, maximising the surface area. When the oxygen enters the alveolus, it dissolves in the cells of the moist alveolar

wall, moving through the wall into the capillary and then to the pulmonary vein.

Explain why cardio-pulmonary resuscitation techniques can maintain life when the heart has ceased beating

All living cells require oxygen. When the heart stops, circulation stops, and cells do not receive oxygen. CPR can maintain life when the heart has ceased beating.

External Cardiac Compression (ECC) provides artificial blood circulation by putting a rhythmic pressure on the chest at regular intervals. This compresses the heart between the breastbone and the spinal column. ECC along with EAR (Expired Air Resuscitation) may be enough to keep the het and brain alive by providing oxygenated blood even when the heart has stopped.

CPR combines EAR (Expired air resuscitation) and ECC (external cardiac compression) to ensure that oxygenated blood continues to reach the brain. The brain can only survive for 4 minutes without oxygen, and by performing CPR a person is effectively carrying out the complete respiratory and cardiac process.

Life may be maintained by the use of CPR, because CPR effectively takes over the breathing and the circulation in a person whose body has stopped carrying out these functions. CPR prevents brain damage by keeping vital organs supplied with oxygen.

Mouth-to-mouth supplies patient with oxygen Heart compressions massage the heart causing it to circulate the blood. This keeps

the oxygen reaching the cells until heart arrives.

Identify that artificial lungs remove carbon dioxide from the blood and replace it with oxygen

Artificial lungs remove carbon dioxide from the blood and replace it with oxygen. In a heart-lung machine, tubes are inserted into the main veins. The blood returning to the heart can then be diverted to the heart-lung machine. Oxygenated blood is pumped back into the aorta (and then into the heart) through another tube.

The heart and lungs must be temporarily stopped during surgery for heart transplants and heart implants. A heart-lung machine is used during these operations to perform the functions of the heart and lungs.

How does it work?- Blood flows into an oxygenator where it is exposed to oxygen- CO2 crosses back to the oxygenator to be removed from the blood

Discuss the type of operations that would require the use of an artificial lung

Artificial lungs may be used to treat patients with acute respiratory distress syndrome, pneumonia and chronic lung disease, as well as organ transplant patients and patients in intensive care.

Artificial lungs are necessary for any patient that must undergo major surgery inside the chest cavity. This includes such operations as open-heart surgery, heart and/or lung transplants, and aortic surgery.

Identify the devices that constitute life support systems in any major hospital

Life support system: An artificial or natural system that provides all or some of the functions necessary for maintaining life or health.

Electrocardiographs (ECGs)

Record the electrical activity of the heart to monitor any problems.

Ventilators Used to supply oxygen to a person who can no longer breathe naturally.

Respirators Machine which induces artificial breathing via a tube inserted in the trachea.

Heart-lung machines Performs functions of heart and lung when stopped during surgery.

Renal dialysis Artificial kidney regulates the concentration of the patient’s blood by removing toxins and adding other substances.

Monitoring devices such as ECG’s and echo-cardiographs (ultrasonic scans of the structural composition of the heart) that allows the heartbeat to be recorded and problems anticipated. For example, echocardiography is used to confirm and determine the seriousness of valve diseases.

Perform an investigation to model the action of the diaphragm in inhalation and exhalation

Air enters the lungs when the chest cavity is expanded. To do this, the ribs are pulled outward & the diaphragm contracts & moves downward. Air is exhaled when the muscles relax & the diaphragm moves up to its original position. Inhalation occurs when the diaphragm contracts (moves down). Exhalation occurs when the diaphragm relaxes (moves up). When the rubber sheath was pulled out it allowed for the balloons to be filled with air. When the rubber sheath went flat again the balloons exhaled the air. This represented the act of inhaling and exhaling and showed how the diaphragm helps aid the inhaling and exhaling.Advantages:

Visual See action of the diaphragm Inflating of lungs

Limitations: Lung cavity (intercostal muscle, ribs) doesn’t move – unlike the “real” thing

Perform a first-hand investigation to identify carbon dioxide in inhaled air and in exhaled air and determine which has the greater concentration

The air we breathe in contains about 21% oxygen and 0.03% carbon dioxide. Immediately exhaled air contains 16% oxygen and 4% carbon dioxide. In this experiment, lime water is the indicator of the presence of carbon dioxide. The greater the amount of carbon dioxide the more precipitate is produced and the “whiter” the solution.

Title: Investigating Carbon Dioxide levels in exhaled and inhaled air.Aim: To identify the differing carbon dioxide levels in inhaled air exhaled air, to determine which (inhaled or exhaled air) has the greater concentration of CO2. Hypothesis: Exhaled air would have a greater concentration of CO2 than inhaled air because…Risk Assessment:

What is the risk Why is it a risk How to prevent the riskIngesting limewater Is very detrimental to health Do not ingest limewater,

gently inhale into limewaterHandling Glassware can cause cuts, creating loss

of bloodHandle with care

Glassware can fall and break Dangerous, can cause cuts, creating loss of blood

Ensure glassware is kept in the middle of lab bench to avoid falling and breaking

Equipment: 120mL of Limewater 3 test tubes Sticky labels and pens Stopwatch/timer

Independent variable: Exhaling and inhaling to limewaterDependent variable: If inhaled or exhaled air contains higher CO2 levelsConstant variables: Same amount of Limewater in each test tube, 40mL, same time when exhaling and inhaling into limewater, 30 seconds, same type of test tube. Control: Limewater exposed to no exhaled and inhaled air.

Method:1.Add 40mL of limewater to 3 identical beakers labelled A, B and C by using sticky labels (writing with pens)2.Immediately start the stopwatch/timer and gently breath/inhale into beaker A for 30 seconds. 3.Immediately start the stopwatch/timer and blow/exhale into beaker B for 30 seconds4.Don’t inhale or exhale into beaker C (controlled).

5.Record observations and compare results with other students, exclude outliers.

Results: Beaker A (inhaled air) Beaker B (exhaled air) Beaker C (No exhaled or

inhaled air exposed, control)The limewater changed very minutely from colourless into a slight milky/whitish colour. Also, minor bubbles were observed.

The limewater changed dramatically/immensely from colourless into a strong milky/whitish colour. Also, rapidly bubbles were observed.

The limewater remained colourless/clear, no bubbles were observed.

Discussion:The aim of the experiment was to determine which (inhaled or exhaled air) has the greater concentration of CO2. Given that limewater forms a milky/whitish colour when exposed to high CO2 levels, this proposed that exhaled air contained the highest level of co2 as beaker B formed a very strong milky/whitish colour as it was exposed to exhaled air. On the other hand, beaker A was exposed to inhaled air, and formed a very slight milky/whitish colour, which proposed that inhaled air contains small concentrations of CO2 in comparison to exhaled air.

The experiment undertaken was reliable, as many students had also followed the experimental method and hence, the results were compared and were consistent. Furthermore, the experiment was accurate as variables were controlled using appropriate equipment, e.g. measuring cylinders were used to measure 40mL of limewater by observing at eye level. The experiment was also valid, as variables were identified and incorporated, e.g. the experimental method accounted for a control, and also variables were controlled, e.g. same amount of limewater etc. These factors further provide that exhaled air forms a strong milky/whitish colour when exposed to limewater, proposing that exhaled air contains higher concentrations of CO2 than inhaled air (given that limewater forms a milky/whitish colour when exposed to high CO2 levels).

These results can be beneficially used as it allows an understanding of why expired air resuscitation can maintain life when the heart has ceased beating. This is because exhaled air still contains 17% oxygen despite exhaled air containing higher CO2 levels in comparison to inhaled air.

Despite the experiment determining that exhaled air contains higher levels of CO2 levels than inhaled air, it did not determine the specific amount of the levels of CO2 and the specific amount of how much more of CO2 does exhaled air contain than inhaled air. However, this can be improved by researching the specific amount of the levels of gases in inhaled and exhaled air, as research proposes that inhaled air contains 21% oxygen, 0.03% carbon dioxide, whereas exhaled air contains 16% oxygen and 4% carbon dioxide. Hence, this research is vital, as it’s more specific when understanding the specific higher amount of CO2 in exhaled air than inhaled air.

Conclusion: The aim of the experiment was to determine which (inhaled or exhaled air) has the greater concentration of CO2. This was easily determined by the lime-water test, which showed that when the limewater was exposed to exhaled air, it formed a very strong milky colour, as limewater forms a very milky colour when exposed to high CO2 levels. However,

when the limewater was exposed to extremely low amounts of CO2 levels. Therefore, exhaled air contains higher amounts of CO2 than inhaled air.

Gather, process and present information from secondary sources to identify monitoring and other devices that constitute life support systems and use available evidence to explain their roles in maintaining life.

Life support systems include: Ventilators – when a person can no longer breathe naturally, an artificial ventilator is

used. Respirators – machine that induce artificial breathing. Air is transmitted to the lungs

via a tube inserted in the trachea. Renal dialysis – the artificial kidney regulates the concentration of the patient’s blood

by removing substances and adding substances selectively.

Device chosen: Kidney Dialysis Machine The kidney dialysis machine is a device which replaces the function of the kidney

when the patient’s kidney is not doing the job adequately. The kidney’s function is to filter blood, remove wastes and toxins from the human body. This dialysis machine filters blood by removing wastes.

It’s connected to a patient through a tube in the patient’s artery in which the blood flows into the device where the blood is filtered. Then a separate tube carries blood back into a vein into the arm.

The kidney dialysis machine as a life support system helps to maintain life by filtering blood which is essential in removing waste from the body. If the wastes were not properly removed, then the toxins would build up and the patient can die as a result.

5. The use of non-invasive or minimally invasive medical techniques has reduced risks to patients and has increased our understanding of how the body works

Discuss the terms non-invasive and minimally invasive in relation to medical techniques

Non-invasive: Non-invasive surgery refers to the performing of a surgical technique without making

an incision in the skin at all. The removal of gallstones using laser treatment is an example of a non-invasive technique currently in use.

Non-invasive diagnostic techniques include ultrasound, x-rays, thermography and magnetic resonance imaging.

Minimally invasive: Minimally invasive refers to techniques that are performed by making the smallest

practical incision in the skin. Keyhole surgery is a recently developed form of minimally invasive surgery. A small

incision is made in the skin, and specially designed surgical tools are inserted through the incision to perform the required tasks. A small camera called an endoscope using optical fibres is also inserted into the hole, so the surgeon can obtain a view on what he is doing. Other examples include laser technology, microsurgery.

Identify non-invasive diagnostic techniques including X-rays, ultrasound, thermography and magnetic resonance imaging (MRI) and discuss their importance in diagnostic medicine

X-RaysX-rays travel through some but not all materials. They pass through skin tissue but not bone. This property is used in diagnostic medicine to get a clear picture of internal structures, such as the skeletal system and organ placement, without invasive, exploratory surgery. X-rays are used to diagnose limb or joint injury fractures of the bone, large tumours and enlarged organs. Mammography’s, or breast X-rays are used as both a diagnostic and screening technique for breast cancer. The disadvantages of X-rays include: they only provide a 2D view, bones often hide other tissues that cannot be seen with X-rays and over exposure can damage tissue and cause cancer.

An X-ray image is produced by passing X-rays through a person and detecting the using a film or digital sensor on the opposite side of the body.

X-rays are absorbed by bone and so areas corresponding to bones show up as light areas on an X-ray image.

X-ray technology is rapidly transforming to a digital process, without the use of film. X-rays are an economical way to diagnose fractures that need medical attention. X-rays are also used in CAT scans which give high resolution images of soft tissue

such as the brain. (used to diagnosed brain tumours). However X-rays are no good forimaging soft tissue damage.

UltrasoundUses ultrasonic sound waves. The sound waves, transmitted from a probe, penetrate the body and are reflected off internal structures. Different layers of tissues and organs reflect the sound differently. The echoes are received and analysed by the probe and converted into an image on the screen. Ultrasound is used in diagnosis and to study foetuses in the uterus.

Sonography uses reflective sound to detect objects inside the body. Ultrasound is extremely safe and can be used for obstetrics and it can show tumours

and some soft tissue injuries. Ultrasound technology is relatively cheap (compared with other scanning

technologies) and widely available. Ultrasound’s disadvantage is that the image does not show fine detail visible in an X-

ray or MRI scan does not require surgical procedures Ill patients can be examined without sedation, and relatively quickly and

conveniently Since sound is non-ionising it does not damage DNA, cells and tissues

Disadvantages of using ultrasound

The images obtained are highly dependent on the operator’s skill Images are not as easy to interpret as x-rays or MRI It is difficult to produced clear images with obese patients (due to sound absorption

and reflection from fat).

The presence of air and bone obscure objects behind them because both reflect ultrasoundstrongly at boundaries with other tissues.

ThermographyUses infra-red waves and differences in body temperature to create images and is useful as a diagnostic technique in locating cancerous tumours. Tumours are more active metabolically and therefore produce more heat. Thermography (or digital infra-red thermal imaging – DITI) also helps identify areas where there is restricted blood flow (in this case the temperature of tissue is lower).

Thermography examinations could prove a simple and less expensive complement to mammography. They are particularly useful for women under 50 where mammography is less effective.

TDITI has been shown to be useful as a diagnostic tool in the diagnosis of neuromusculoskeletal injuries and their prognosis for return to participation in sport.

Magnetic Resonance Imaging (MRI)Also called nuclear magnetic resonance. MRI uses radio waves and the body’s water molecules to create images. The MRI machine produces a powerful magnetic field that causes hydrogen atoms in water to line up parallel to the direction of the field. The machine then releases radio waves that cause a shift in the hydrogen atoms. The hydrogen atoms are then allowed to return to their earlier position. This brief change is recorded and analysed.MRI can be used for diagnosis because not all body tissue contains the same amount of water. Hard tissue such as bone, for example, contains little water. MRI is used therefore to clearly identify soft tissue such as the brain and spinal cord, which are encased in bone.

Magnetic resonance imaging is a technique of scanning the body. It is based on the fact that living tissues give off their own special electromagnetic signals, depending on the water content of the tissue.

If the tissue is subjected to a large external magnetic field, the small electromagnetic signals may be detected and built up to form a 3D image.

MRI is a popular diagnostic technique, as it ignores bones (as they contain little water), concentrating on soft tissue. In this respect, MRI is the opposite of x-rays, which tend to concentrate on the bones.

Describe the advantages of using minimally invasive surgery techniques such as keyhole surgery

Minimally invasive medical techniques, such as keyhole surgery, have several advantages over standard surgical techniques (i.e. those techniques requiring larger incisions). They involve:

smaller incisions less post-operative pain fewer complications from healing wounds minimal scarring quicker recovery time shorter hospital stays and so they are cheaper.

Minimally invasive techniques refer to minor surgery that has little effect on the body and only uses small cuts to access the inside of the body. Techniques include endoscopy and keyhole surgery.

An endoscope is a thin plastic tube containing optical fibres. A tiny camera can also be placed at the end of the endoscope and images are shown on a screen. They are often inserted via a ‘keyhole’ which is a tiny incision in the body. Endoscopes are used in gynaecology, cardiac bypass surgery and in the thoracic cavity to remove lumps on the surface of the lung and take samples for analysis.Identify data sources, gather, process, analyse and present information to discuss the advantages and disadvantages of non-invasive and minimally invasive medical techniques.

Non-invasive techniquesAdvantages – less risk to patient, fewer side effects, less chance of infections, faster recovery time, less need for medication.Disadvantages – limited number of treatments per year (x-rays have radiation).

X-rays – Advantages: cheap, widely available, provides images of bones and internal organs.Disadvantages: only 2D, may be hard to interpret, cannot see structures deep within tissue,number of x-rays must be limited (as it can damage or destroy tissue: cancer).

CAT scan – Advantages: clearer than x-ray, allows the changes in organs as they work to beviewed, e.g. blood flow. Disadvantages: require more skill to interpret images, more expensive.

Ultrasound – Advantages: can examine many areas of the body, pregnancy: no risk to mother or baby. Disadvantages: cannot determine conditions of the bone or lungs.

MRI – Advantages: provides very detailed images, good for diagnosis of many conditions (MS,tumours, infections, strokes), 3D, no radiation. Disadvantages: some people cannot have MRI(pacemakers, dentures), long procedure, very expensive, difficult for claustrophobic patients.

Thermography – Advantages: large areas can be assessed, safe and fast, no pain or radiation.Disadvantages: extremely expensive, images are hard to interpret.

Minimally invasive techniquesAdvantages – keyhole: allows surgeon to view inside the body without making large incisions, smaller scars, less pain, less risk of infectionDisadvantages – endoscopes only allow a small area to be illuminated at a time, may not detect some conditions, risk of infection

Keyhole Surgery – Advantages: less risk of infection, under general anaesthesia, less pain and body trauma, less scarring of body and faster recover for patient. Disadvantages: The doctor may not have as clear or wide a view of the area, this surgery can be difficult, and this surgery may take longer.

Gather, process and analyse information and use available evidence to discuss how technological developments have impacted on the understanding of how the body works

The development of X-ray machines had a huge impact on our understanding of how the body works. For the first time, doctors could look inside the body without cutting it open. X-rays allow doctors to see bone fractures and to study the healing process.

Ultrasound is a safe technique to use with pregnant women. It can be used to monitor the development of the foetus during pregnancy and has provided a great deal of information about the development of the human embryo especially in the early stages. Three-dimensional ultrasound imaging is a technique that allows for clearer images of internal organs and is allowing doctors to study the development of growths such as fibroids and polyps. The technique of echocardiography uses ultrasound to form images of the heart. This technique helps doctors to understand the action of heart muscles and valves. MRI can be used to scan the body using a large magnetic field. It analyses electromagnetic signals given off by living tissues and is based on the water content of tissues. The ability of MRI scans to provide clear three-dimensional images of soft tissues has improved our understanding of the structure and functions of the body components. For example, it has increased our knowledge of brain functioning by pinpointing areas of the brain which respond to certain stimuli.

Biotechnology is an area of science which combines our knowledge about organisms with the developments of applied science. Nanotechnology is the study or use of very small structures (a nanometre is 10-9 metres).

The 4 areas of current research in biotechnology are:1) Bioengineering2) Tissue engineering3) Biosensing4) Biological nanotechnology

We should fund research in these areas because they play an invaluable role in saving lives and improving the quality of life for many people. They also help in our quest for knowledge. In future years the information discovered may have applications far beyond our present understanding.