Past Exam Papers Flashcards
A surgeon recently said “A malignant neoplasm of the skin has the potential to affect every organ and system in the body.” Please say whether you agree or disagree with this statement, and then explain what the surgeon meant.
I would agree, because a malignant neoplasm can metastasize elsewhere in the body where it may grow and block ducts, replace tissue, or compress tissue, in an area where damage/death of tissue is life-threatening.
Define each of the following:
(1) ischemia
(2) hypoxia
(3) anoxia
(1) ischemia, A reduction in the supply of oxygenated blood to an area (
2) hypoxia A reduction in the amount (or concentration) of oxygen
(3) anoxia. A lack of oxygen
A physiologist recently said “External compression of a vein draining an organ can be just as damaging as external compression of an artery supplying blood to that organ.” Please explain their statement.
If the removal of blood from an organ is reduced or completely blocked, then blood will back up in the organ and reduce or prevent the incoming flow of oxygenated blood, causing hypoxia (or even anoxia) which can result in cell damage or death. Therefore, compression of a vein can have the same effect as compression of an artery.
Define ‘preload’ and ‘afterload’.
’Preload’ is the pressure exerted on the wall of the heart when it fills with blood and therefore stretches during diastole. Afterload is the pressure (in the artery) against which the heart must overcome (or ‘work against’) to pump its contents into that artery.
What is left systolic heart failure?
and
What are two common causes of this condition?
This is when the left hand side of the heart has a reduced ability to contract and therefore deliver sufficient cardiac output to meet the needs of the body.
Causes
- Increased afterload as a consequence of atherosclerosis and increased peripheral resistance
- Narrowing of the coronary arteries, resulting in ischemia of heart tissue.
Please compare and contrast emphysema, chronic bronchitis, and asthma, including giving any common features of these conditions.
Similarities
all are obstructive pulmonary diseases and reduce gas exchange in the lungs
Differences
- ASTHMA is reversible,
- Emphysema and Chronic bronchitis are chronic progressive conditions.
- Emphysema is scarring of alveoli,
- chronic bronchitis is the inflammation and thickening of the walls of the bronchi, leading to narrowed airways. Asthma is the widespread reversible narrowing of airways.
- Emphysema and chronic bronchitis are frequently associated with cigarette smoking.
- Asthma appears to be caused by an over-responsive immune system.
What effect does hypokalemia have on the resting potential of a nerve cell and how does this affect the function of this cell?
This will decrease the resting potential, making the cell less likely to reach the threshold potential when it is stimulated and therefore less likely to fire.
hypokalemia=a lower amount of potassium in the blood
Define each of the following:
(1) renal insufficiency
(2) end stage renal failure
(3) uraemia.
_ renal insufficiency_ When renal function has reduced to 25%,
end stage renal failure When renal function is reduced to 10%,
uraemia. The collective symptoms of renal failure, and which include increased urea levels in the blood, fatigue, nausea and itching.
What occurs in the brain when a person has an epileptic seizure?
Why are many epileptic seizures accompanied by severe convulsions?
An epileptic seizure is caused by the uncontrolled discharge of neurons in the cerebral cortex. It usually starts at a particular point and spreads across the cerebral cortex.
Convulsions occur when the discharge spreads to cells of the primary motor cortex and result in action potentials being sent from there to muscles in the body.
What part of the CNS is damaged when a person has multiple sclerosis, and what type of damage occurs to the affected tissue?
MS affects myelinated nerves within the CNS.
The immune system attacks the myelin sheath of these cells, resulting in inflammation and interference with the transmission of action potentials.
Compare and contrast diverticulitis and diverticulosis.
diverticulitis = inflammation of diverticuli
diverticulosis = The presence of diverticuli – blind pockets that form from herniation of the wall of the large intestine, and are usually caused by high pressure within the intestine.
Explain why people who suffer from chronic gastritis are often anaemic.
This is chronic inflammation of the lining of the stomach.
The stomach lining secretes intrinsic factor, which improves the absorption of vitamin B12 across the wall of the small intestine.
Vitamin B12 is needed for the formation of red blood cells.
Secretion of intrinsic factor is reduced if the stomach lining is inflamed, so absorption of B12 is also reduced.
A rare disease of humans called ‘post-viral cortisone crisis’ occurs following a minor viral infection such as the common cold. The immune system makes antibodies that bind to the virus, but unfortunately the shape of these antibodies is almost identical to the hormone cortisone. What would be the consequences and symptoms of post-viral cortisone crisis?
If the antibodies resemble cortisone they will have the same effect as that hormone. Therefore the person will have a greatly reduced immune response and be extremely susceptible to infection.
What is osteoarthritis and why does its incidence increase with age?
Osteoarthritis is damage to a joint that results in reduced movement and minor inflammation.
It occurs as a result of ‘wear and tear’ so the incidence increases with age as damage accumulates.
Why does kidney dysfunction often lead to a person suffering from a form of arthritis?
When the ability of the kidneys to remove urea from the blood is reduced due to dysfunction the concentration of this waste will increase in the person’s bloodstream.
Therefore, crystals of uric acid can be precipitated in the joint cavity, interfering with the movement of synovial joints and causing pain and inflammation.
There are three common types of skin cancer: (a) squamous cell carcinoma, (b) basal cell carcinoma and (c) malignant melanoma. Please compare and contrast all three.
All are neoplasms of the skin and are more common on sun-exposed skin.
Basal Cell Carcinoma *benign ** from the stratum basale
Squamos cell Carcimona *malignant ** rises from the stratum spinosum
Malignant melanoma *malignant ** from the stratum from melanocytes in the stratum basale
.
What is polycystic ovary disease and what hormonal imbalance is thought to be responsible for it?
This is when ovarian follicles never mature sufficiently to release their ova, thereby forming many cysts in/on the ovary. It is thought to be caused by a deficiency of FSH.
What is the most common cause of carcinoma of the cervix?
Why is early diagnosis of this condition particularly important?
The human papilloma virus.
Early diagnosis is important because this neoplasm can metastasize elsewhere after an initial latent period.
Define
Glaucoma.
Cataracts
Retinal detachment.
Conjunctivitis.
Retinitis pigmentosa.
Meniere’s syndrome.
- *Glaucoma.** Intraocular pressure greater than 21 mm Hg.
- *Cataracts.** An opacity of the lens of the eye.
- *Retinal detachment.** Detachment of the retina from the choroid layer
- *Conjunctivitis.** Inflammation of the conjunctiva
- *Retinitis pigmentosa.** Death of cells of the retina, giving the impression of dark patches (where the cells have died) on examination
- *Meniere’s syndrome.** Accumulation of excessive fluid in the semicircular canals in the inner ear, resulting in dizziness and possibly nausea
Please compare and contrast presbyopia, hyperopia and myopia.
MUST KNOW
All are disorders of the eye that interfere with focus.
Presbyopia is the inability to focus on close objects and becomes worse as we age. It is caused by the lens in the eye becoming progressively more rigid.
Myopia is the inability to focus on distant objects. It is caused by the eyeball being too long.
Hyperopia is the inability to focus on close objects, but is caused by the eyeball being too short.
Two people had identical surgery to remove a single 3 cm diameter tumour from
exactly the same part of their large intestine. Both were treated by the same
surgeon. A week later the first person was told ‘There is no need for any further
surgery.’ The second was told ‘More surgery is needed and we need to examine
your liver and other organs for neoplasms’. Please explain, in relation to the two
main categories of neoplasia, why the two people were given such different advice.
It seems the first person had a benign neoplasm and the second had a malignant one. Benign neoplasms are slow growing single tumours that are often encapsulated and do not metastasise (or you could say “do not spread elsewhere”). In contrast, malignant tumours are fast growing, show radiating growth and often metastasise. Venous blood from the intestines flows through the liver on the way to the heart, so the liver is a prime location for secondary growths of intestinal tumours.
There are five main ways in which an artery can be obstructed. Please name and
describe each of these. Diagrams are likely to help your explanation.
A thrombus is a blood clot (made up of platelets and fibrin) attached to the inside wall of an artery or vein.
An embolus is a foreign object that circulates in the bloodstream until it becomes lodged in a vessel. Types of emboli include blood clots, fat, fibrofatty material and air.
Arteries can also be obstructed by compression, structural changes, or spasm
What is a dissecting aneurysm?
A dissecting aneurysm doesn’t involve a stretching of all the layers in the wall of the artery. Instead, following
a break in the inner wall of the artery (the tunica intima), blood is forced between the tunica intima and either
the tunica media or tunica externa.
What is a false aneurysm
A false aneurysm is a clot attached to the outside of an artery following rupture of the vessel.
Explain why, and how, severe emphysema can lead to the development of right side heart failure.
Severe emphysema results in the loss of alveoli and therefore the loss, or scarring, of the capillaries in the lung.
This reduction in functional capillaries increases peripheral resistance so blood in the pulmonary artery will be under high pressure.
This increases the afterload for the right side of the heart.
The right side of the heart will hypertrophy in order to keep pumping the required amount of blood into the pulmonary artery but will eventually outgrow its coronary blood supply, weaken and fail.
Explain the difference between preload and afterload.
Preload is the extent to which the ventricle is stretched as it fills with blood.
Afterload is the pressure in the artery taht the heart has to pump against to empty its contents into that artery.
Please compare and contrast emphysema, chronic bronchitis and asthma,
including discussion of the causes of each condition.
All three are classified as obstructive pulmonary diseases
Emphysema is the irreversible scarring and loss of alveoli in the lung. A common cause is chronic cigarette smoking, but it may occur in a person who already has chronic bronchitis.
Chronic bronchitis is the chronic inflammation of the inner lining of the bronchi. Eventually the airway becomes irreversibly scarred and narrowed. Common causes are repeated lung infections, exposure to pollution or cigarette smoking.
Asthma is the reversible narrowing of the bronchioles and bronchi due to contraction of smooth muscle in the walls of the airways. This is often an allergic response to dust or pollen.
What effect does hypercalcaemia have upon the functioning of nerves? Why?
Hypercalcaemia is a high concentration of calcium in the blood.
It makes nerves unresponsive and therefore less likely to fire.
The high concentration of calcium increase the threshold of nerve cells.
Blockage of a ureter can damage a person’s kidney in two ways. What are these
and how does the damage occur?
- It can cause urine to back up in the pelvis of the kidney. Bacteria can therefore build up because the blockage will prevent them from being washed out. The bacteria can cause inflammation and infection of the kidney.
- Second, the pressure of the urine behind the blockage can compress blood vessels in the kidney, causing ischemia and therefore cell death.
Compare and contrast thrombotic, embolic and haemorrhagic strokes
All three result in a loss of blood supply to the brain and therefore ischemia to brain tissue.
- A thrombotic stroke is caused by a blockage that forms in an artery or arteriole supplying the brain.
- An embolic stroke is also caused by a blockage, but in this case the blockage is the result of material that has come from elsewhere (e.g. fat, air or a detached thrombus) in the circulatory system.
- A haemorrhagic stroke is caused by a blood vessel rupturing in the brain.
What are the causes and consequences of myasthenia gravis?
This is caused by antibodies binding to and eventually destroying the receptors for acetylcholine in the junction between peripheral nerves and muscles
This reduces synaptic transmission so the person has muscle weakness.
It is caused by an autoimmune response where the immune system makes antibodies that just happen to fit the receptor proteins.
What are two consequences of chronic gastritis
- An increased risk of stomach ulcers and cancer of the stomach.
- Anaemia. This is due to reduced production of intrinsic factor. Intrinsic factor is released by cells in the stomach. It binds to vitamin B12 and helps the absorption of this vitamin (which is needed to produce red blood cells) in the small intestine.
Please define glaucoma and compare and contrast open angle glaucoma and closed angle glaucoma.
Glaucoma is pressure inside the eye of greater than 21 mm Hg.
Open angle glaucoma occurs when the front of the eye (you didn’t have to put “anterior chamber”) is of normal shape but the canal of Schlemm (or Schlemm’s canal, or a word that looks like Schlemm and I even accepted ‘”Canal of S- - - - - sorry Steve, I can’t remember) becomes blocked, often by debris from the eye. This impedes the drainage of fluid, so pressure in the eye rises. This pressure can compress the cells of the retina and blood vessels, causing ischemia and death of retinal cells.
Closes angle glaucoma is when the front of the eye (you didn’t have to put “anterior chamber”) is narrowed, so there is very little space between the iris and the cornea. There isn’t any internal blockage of Schlemm’s canal, but when the iris pulls back in dark conditions it bunches up and blocks the opening of the canal. So pressure rises every night, but is released during the day when the iris extends outwards and stops blocking the opening. The high pressure can compress the cells of the retina and blood vessels, causing ischemia and death of retinal cells.
List five ways in which an artery can become obstructed.
thrombus, embolus, compression, structural changes and contraction of smooth muscle in the wall of the artery.
(a) List the layers of skin affected by a first, second, and a third degree burn.
First: epidermis;
Second: epidermis and dermis;
Third: epidermis, dermis and hypodermis.
(b) Draw the basic structure of the male reproductive system and use this to explain why benign prostatic hypertrophy can affect the health of the kidneys.
An enlarged prostate may compress the urethra, resulting in reduced washout and increased pressure of urine on the kidney.
(a) Define glaucoma and then compare and contrast open and closed angle glaucoma.
The definition of glaucoma is ‘when pressure inside the eye is greater than 21 mm Hg’
Open angle glaucoma is when the eye is normal but the canal of Schlemm (or Schlemm’s canal) is obstructed.
Closed angle glaucoma is when the anterior chamber of the eye is very narrow and the iris blocks Schlemm’s canal whenever it retracts.
(b) Using a diagram, explain what happens when the retina detaches and explain why this can permanently affect a person’s vision.
n that the cells of the retina get their oxygen from the blood vessels in the choroid layer so experience hypoxia when detached.
