Medical Technology: Bionics Experiments

OUTCOME 2:2.10 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

The heart rate increases when you exercise because your heart and body requires more oxygen and must get rid of carbon dioxide at a faster rate.

The heart beats faster and therefore the pulse rate increases.

The heart rate of different people will vary due to a variety of factors:- Level of fitness – people with high levels of fitness tend to have faster recovery rate after exercise- Food intake before investigation- Individual differences e.g. body weight

Independent variable: amount of activityDependent variable: rate of the heartbeatControlled variables: pace of exercise, timing of exercise

Conclusion—the heart rate changes as the level of physical activity changes. This is because as the pulse rate increases, the body and heart require more oxygen. The cardiovascular system links to the respiratory system to work the body’s muscles. The body and heart needs to get rid of carbon dioxide at a faster rate.

2.11 plan and perform an investigation to identify individual aspects that comprise the heartbeat

The heart contracts in the SYSTOLE phase and relaxed in the DIASTOLE phase.

The opening and closing of the heart valves cause “lub dub” sounds.

An electrocardiogram records the electrical activity of the heart as it goes through its rhythmic beating process.

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Electrocardiogram (ECG):

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TP

interval (ventricular diastole): atria and ventricles are relaxed; blood flowing into atria via veins.P wave (atrial systole): SA node fired, atria contracts, forcing all blood into ventricles.QR interval (end of ventricular diastole): the AV valves remain open as all the remaining blood is squeezed into ventricles.RS interval (ventricular systole): as the blood is now all within the ventricles and so pressure is higher here than in atria, the AV valves close. The ventricles start to contract.ST segment (ventricular systole): pressure increase, causing the SL valves to open, blood is ejected into aorta as ventricles contract.T wave (ventricular diastole): ventricles relax; pressure reduced; causing SL valves to close.

2.12 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

1950 Pacemaker worn externally, had external power source

1952 Pacemaker is able to be implanted into patient through surgery

1957 Battery-powered pacemaker1958 Internal pacemaker1959 Successful implantable pacemaker1960s Leads that could be fixed to the heart via a vein was

introduced1970s Leads with pronged or screw in ends were

developed; coating of pacemaker were improved to titanium

1990s More sophisticated, much smaller in size, more data can be stored in them

Early pacemakers delivered an electric shock to the heart

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of the person; device was plugged to wall socketTechnological advances that led to the development of the modern day pacemaker:

1. Leads that attach to the wall of the heart 2. Portable battery3. Surgically implanted4. Development of smaller pacemakers 5. Improvements in design, battery life, materials used,

reprogramming outside the body 2.13 process information to identify different types of functions of artificial valves in the heart

Mechanical valves E.g. ball and cage metal, disc in cage, bileaflet valve Ball and cage—metal housing with carbon discs; they

replicated the function of normal heart valves; very durable

Bileaflet valve—two semi-circular discs which open and close; replicate function of normal heart valve; last indefinitely

Biological valves E.g. pig, calf, human Made from animal tissue; is treated so it won’t be

rejected by recipient; less chances of rejection; degenerate gradually (need replacements)

OUTCOME 3:

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

Bones consist of living and non-living parts. The non-living part is made up of calcium which keeps the bones hard & rigid. The living part includes strands of protein, called collagen, which gives bones flexibility.

By removing the calcium in a chicken bone, via hydrochloric acid, the hardness of the bone is removed.

Calcium & organic matter gives strength to bones.

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

Cartilage is a bluish white rubbery tissue found in humans. It is found at the ends of bones & cushions the bone against shock (shock absorber) which reduces friction. Muscles make the body move. The hold bones of the skeleton together. Muscles

move bones by pulling on tendons.A tendon is a strong white cord which connects muscle to bone. When bones meet a joint is formed. Ligaments tie the bones together at the joints (bone to bone).

3.13 perform an investigation to demonstrate the different types of joints and the range of movements they allow

Types of synovial joints in the body;Body part Range of movement

of the jointType of synovial joint

Shoulder, hip - Side to side- Back & forth- Rotational movements

Ball and socket joint

Elbows, knees, ankles - Back & forth Hinge jointBase of thumb - Back & forth

- Side to sideDouble hinge joint

Spinal bones, tarsal - Back & forth Sliding/gliding joint

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bones of feet & hands - Side to sideBase of skull (neck) - End of one bone

rotates inside a ring formed by the other bone

Pivot joint

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

Comparing bone to cartilage, which has greater shock absorbing ability, why?

Cartilage has greater shock absorbing ability than bone because it is flexible.

Discuss the shock absorbing ability of the different parts of the bone (e.g. cartilage, tendons, muscle):

A bone is generally made up of 2 types of tissue; spongy & compact bone. The spongy, porous part of a bone is less dense & has lower shock absorbing ability. Compact bone is much denser & therefore has a higher rate of shock absorption e.g. arms, legs.

Conclusion – different parts of the bone have different shock absorbing abilities due to their density & structure. The bone has different elasticity than the cartilage between the bones. Cartilage is designed to absorb more shock because it acts as a “cushion” between the bones. It is flexible but strong, supportive tissue.

3.15 plan, choose equipment or resources for

Relating to silicone...Flexibility – very flexible, soft and sticky

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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

Resistance to acid – high resistance, does not change shape & hardens slightly to stay togetherImperviousness to water – high imperviousness, silicone is not penetrated by waterEffect of body temperature – hardens and sticks to itself

Independent variable: condition in which the silicone sample is subjected toDependent variable: flexibility, acid resistance, water imperviousnessControlled variables: time, amount of silicone

Silicone has the characteristics of being inert, flexible, water resistant, acid resistant, and easy to shape which makes it an optimal material for the use in bionics.

3.16 analyse secondary information to compare the strength of UHMWPE and “superalloy” metal

Comparison of stainless steel & titanium alloys;Property Stainless steel Titanium alloy UHMEPE

Ultra high molecular weight polyethylene

Tensile strength 960 960 17Elasticity 200 110 700Density 7.8 4.5 0.95

OUTCOME 4:4.6 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 – diaphragm contracts (moves down)Exhalation – diaphragm relaxes (moves up)

4.7 perform a first-hand The air we breathe in contains about 21% oxygen &

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investigation to identify carbon dioxide in inhaled air and in exhaled air and determine which has the greater concentration

0.03% carbon dioxide. Immediately exhaled air contains 16% oxygen & 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 & the “whiter” the solution.

4.8 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.

Kidney dialysis machineThe 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 & toxins from the human body.

This dialysis machine filters blood by removing wastes. It is 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 & the patient can die as a result.

OUTCOME 5:5.4 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 techniquesGeneral advantages – less risk to patient, fewer side effects, less chance of infections, faster recovery time, less need for medication.General disadvantages – limited number of treatments per year (x-rays have radiation)

Advantages & disadvantages of non-invasive techniques;

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X-rays – Adv; cheap, widely available, provides images of bones & internal organs. Dis; only 2D, may be hard to interpret, cannot see structures deep within tissue, amount of x-rays must be limited (as it can damage or destroy tissue: cancer)CAT scan – Adv; clearer than x-ray, allows the changes in organs as they work to be viewed, e.g. blood flow. Dis; require more skill to interpret images, more expensiveUltrasound – Adv; can examine many areas of the body, pregnancy: no risk to mother or baby. Dis; cannot determine conditions of the bone or lungs.MRI – Adv; provides very detailed images, good for diagnosis of many conditions (MS, tumours, infections, strokes), 3D, no radiation. Dis; some people cannot have MRI (pacemakers, dentures), long procedure, very expensive, difficult for claustrophobic patients.Thermography – Adv; large areas can be assessed, safe & fast, no pain or radiation. Dis; extremely expensive, images are hard to interpret

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

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

How the discovery of ultrasound led to the understanding of blood flow in the body

A Doppler ultrasound is a non-invasive test that can be used to estimate the blood flow in blood vessels by bouncing high-frequency soundwaves (ultrasound) off circulating red blood cells. A regular ultrasound uses soundwaves to produce images, but can’t show blood flow.

It may help to diagnose many conditions – blood clots, poorly functioning valves in leg veins (venous insufficiency), heart valve defects and congenital heart disease, blocked arteries, decreased blood circulation to legs (peripheral artery

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disease), bulging arteries (aneurysms), narrowing of arteries.

How the discovery of x-rays led to the understanding of bones and its movements

The x-ray machine helped to revolutionise how doctors detected disease & injury. X-rays were used in treatment of illnesses like real & imaginary pains. The discovery allowed doctors to see inside the human body for the first time without surgery. X-rays provided insight into our skeletal systems which was an important step in understanding how the human body functions – movement-wise.

How antibiotic developments were important in understanding how the body’s immune system works

Antibiotics are a group of medicines that are used to treat infections caused by bacteria & certain parasites. Antibiotics do not aid the immune system, it weakens it but replaces one of its functions. They only work on bacterial infections – these chemicals kill the bacteria cells but do not affect cells that make up the body.

Sometimes the body’s immune system is unable to activate itself quickly enough to outpace the reproductive rate of harmful bacteria. Other times, the bacteria are producing toxins so quickly they will cause permanent damage before the immune system does it jobs. In these cases, the immune system needs help from something that can kill the invading bacteria directly (antibiotics).

Senior Science – By Natalie C 2014