Practice Exam Questions

Question 1

Osmosis is an example of a transport mechanism by which
A. metabolic energy is used to transport water across a membrane
B. water diffuses passively from high to low solute concentration
C. water diffuses passively from low to high solute concentration
D. ions are moved down a concentration gradient
E. a selective membrane causes movement of small molecules by active transport

Answer 1

C

Question 2

Which of the following statements is CORRECT regarding transport across cell membranes? Both facilitated diffusion and active transport
A. can generate electrical potentials across cells
B. require the solute to dissolve in the phospholipid bilayer
C. can be mediated by ion channels
D. use proteins to mediate transport across the cell membrane
E. require energy from ATP

Answer 2

B

Question 3

Which statement regarding the relative refractory period is INCORRECT?
A. The membrane potential becomes hyperpolarised
B. It occurs after the absolute refractory period
C. Sodium channels remain completely inactivated
D. A stronger depolarisation is required to bring the membrane potential to threshold compared with the neuron at resting potential
E. Voltage-gated potassium channels remain open

Answer 3

C

Question 4

When a muscle fibre is stimulated by its neuron to contract, which substance is released from which structure?
	A.	K+ from secretory vesicles
	B.	Na+ from the T tubules
	C.	Ca2+ from the T tubules
	D.	Na+ from the sarcoplasmic reticulum
	E.	Ca2+ from the sarcoplasmic reticulum

Answer 4

E

Question 5

What term refers to the branching of axon terminals so that a single cell synapses with -and influences- many other cells?
	A.	bifurcation
	B.	divergence
	C.	integration
	D.	convergence
	E.	termination

Answer 5

B

Question 6

Which blood vessels have the greatest compliance?
	A.	arterioles
	B.	capillaries
	C.	veins
	D.	arteries
	E.	metarterioles

Answer 6

C

Question 7

Which of the following statements about the cardiac cycle is CORRECT?
A. During isovolumetric ventricular relaxation, the ventricular pressure is less than atrial pressure
B. The second heart sound occurs when the atrioventricular (AV) valves close
C. The semilunar valves open when the pressure in the atria is greater than the pressure in the ventricles
D. During diastole, the ventricular pressure is greater than aortic pressure
E. The first heart sound occurs when ventricular pressure is greater than atrial pressure

Answer 7

E

Question 8

Which of the following is NOT an effect of the sympathetic nervous system on the cardiovascular system?
A. increased arteriolar vasodilation
B. increased stroke volume
C. increased contractile strength of the heart
D. increased heart rate
E. increased total peripheral resistance

Answer 8

A

Question 9

Which of the following control mechanisms will cause vasodilation of arterioles?
A. increase in CO2
B. stimulation of the parasympathetic nervous system
C. decrease in H+
D. increase in O2
E. stimulation of the sympathetic nervous system

Answer 9

A

Question 10

The baroreceptors compensate for a decrease in blood pressure by
A. increasing parasympathetic nerve activity
B. increasing vasodilation
C. increasing stroke volume
D. decreasing sympathetic nerve activity
E. decreasing heart rate

Answer 10

C

Question 11

The respiratory membrane of an alveolus has three components. The three components are
A. type II alveolar cells, endothelial cells and the fused basement membranes
B. type I alveolar cells, endothelial cells and the fused basement membranes
C. type II alveolar cells, endothelial cells and surfactant
D. alveolar macrophages, endothelial cells and the fused basement membranes
E. type I alveolar cells, endothelial cells and surfactant

Answer 11

B

Question 12

During inspiration
A. the intra-alveolar pressure is the same as atmospheric pressure
B. the intra-alveolar pressure is less than atmospheric pressure
C. the intra-pleural pressure increases as the lungs expand
D. the intra-alveolar pressure increases as the lungs expand
E. the intra-alveolar pressure is greater than atmospheric pressure

Answer 12

B

Question 13

The inspiratory capacity plus the expiratory reserve volume is referred to as the
	A.	tidal volume
	B.	total lung capacity
	C.	functional residual capacity
	D.	residual volume
	E.	vital capacity

Answer 13

E

Question 14

Which of the following statements about CO2 gas exchange and transport is CORRECT?
A. CO2 will move from the tissue cells into the systemic capillaries when the PCO2 is higher in the capillaries than in the tissue cells
B. CO2 binds to the haem component of haemoglobin
C. Most CO2 is transported in the blood bound to haemoglobin
D. An increase in PCO2 causes a decrease in H+ in the blood
E. The binding of CO2 to haemoglobin decreases the ability of O2 to bind to haemoglobin

Answer 14

E

Question 15

Pulmonary surfactant
A. is produced by type I alveolar cells
B. causes respiratory distress syndrome in premature babies
C. reduces surface tension in alveoli
D. decreases the amount of water in the alveoli
E. prevents collapse of bronchioles

Answer 15

C

Question 16

The absorption of a drug which is a weak acid and administered orally will be greatest in the
	A.	kidney
	B.	small intestine
	C.	large intestine
	D.	mouth
	E.	lung

Answer 16

B

Question 17

Hepatic first pass metabolism
A. reduces the bioavailability of inhaled drugs
B. increases the bioavailability of drugs delivered intravenously
C. increases the rate of absorption of oral drugs
D. reduces the distribution of all drugs
E. reduces the bioavailability of oral drugs

Answer 17

E

Question 18

Which of the following statements about non-competitive antagonists is CORRECT? Non-competitive antagonists…
A. increase the maximum effect that can be produced by high concentrations of agonist
B. have the same efficacy at receptors as agonists
C. have zero efficacy at receptors
D. bind to enzymes and enhance their function
E. bind to receptors at the same site as agonists

Answer 18

C

Question 19

Drugs which act as calcium channel blockers are used in the treatment of hypertension because they cause
	A.	venoconstriction
	B.	vasoconstriction
	C.	increased venous return
	D.	increased stroke volume
	E.	vasodilation

Answer 19

E

Question 20

Glyceryl trinitrate, used in the treatment of acute attacks of angina, is administered sublingually (under the tongue) because it
A. causes stomach ulcers if administered orally
B. undergoes extensive first pass metabolism in the kidney and has low oral availability
C. undergoes extensive first pass metabolism in the kidney and has high oral availability
D. undergoes extensive first pass metabolism in the liver and has low oral availability
E. causes bronchoconstriction if administered by inhalation

Answer 20

D

Question 21

Salbutamol, a β2-adrenoceptor agonist, causes bronchodilation and is used in the acute treatment of
	A.	hypertension
	B.	hayfever
	C.	chronic back pain
	D.	asthma
	E.	angina

Answer 21

D

Question 22

Bioavailability is the fraction of an oral dose that
A. reaches the circulation
B. is absorbed into the portal circulation
C. is metabolised in the gastrointestinal tract
D. is metabolised by the liver
E. is bound to plasma proteins

Answer 22

A

Question 23

A patient has been taking drug X for several months. Despite instructions by his doctor, he begins taking drug Y which leads to adverse side effects that he did not experience in the past when he was taking Drug X alone. Which of the following is NOT a plausible explanation for this scenario?
A. Drug X increasing the absorption of drug Y
B. Dose-related toxicity of drug X
C. Drug Y causes induction of a cytochrome P450 enzyme that converts drug X to toxic metabolites
D. Drug X causes irreversible inhibition of a cytochrome P450 by drug X that is responsible for the metabolism of drug Y
E. Drugs X and Y competing for an enzyme that is responsible for their metabolism to inactive metabolites

Answer 23

B

Question 24

Explain how binding of a messenger (such as a hormone) to an intracellular receptor causes the production of a protein.

Answer 24

?

Question 25

Explain the function AND location of ribosomes in the cell.

Answer 25

Ribosomes are needed for protein synthesis. There are two types: free ribosomes and bound ribosomes.
Free ribosomes are suspended in the cytosol and have proteins that function in the cytosol. Whereas bound ribosomes are bound to the endoplasmic reticulum where the proteins function in the membrane, within an organelle, outside of the cell.

Question 26

a) Define the concept of bulk flow in the cardiovascular system. [1 mark]
b) Explain the two forces that influence the direction of bulk flow. [4 marks]

Answer 26

Bulk flow is the movement of fluid and solutes between the capillaries and interstitial fluid.

Two forces:

1. Capillary Hydrostatic Pressure: This is the pressure of the blood pushing against the capillary wall and it tries to push fluid out of the capillary
2. Blood Colloid Osmotic Pressure: This is the pulling force generated by plasma proteins inside the blood. This pressure tries to pull the fluid from the interstitial space into the blood by osmosis.

Question 27

Frank is admitted to hospital with difficulty breathing. He completes a series of tests including spirometry. The following flow-volume loop compares his results with a normal control patient.
(note: decreased PEF, decreased FVC, increased PIF)

a) List THREE (3) lung function values that can be determined from this graph. [1.5 marks]
b) What is the most likely diagnosis for Frank? [1 mark]
c) Explain why Frank’s inspiration is different to the normal control. [2.5 marks]

Answer 27

A) peak expiratory flow, forced vital capacity, peak inspiratory flow

B) Emphysema because he has reduced PEF and FVC and increased PIF

C) The PIF is increased in emphysema. This is because emphysema causes reduced elastic recoil of the lung because of the breakdown of elastic fibres in the lung. Inspiration is muscle activity working against elastic recoil. So if you decrease elastic recoil, there will be less resistance to expansion of the lungs and this will make inspiration easier and will therefore increase PIF.

Question 28

In Australia about 2 million people suffer from asthma, and about 400 patients die from asthma every year.

a) Discuss the main causes or mechanisms that lead to increased small airway resistance in asthma. [2 marks]

b) Briefly discuss the mechanisms of actions of ONE (1) class EACH of preventer and reliever medications. [4 marks]
(i) Preventer medication:
(ii) Reliever medication:

c) Name FOUR (4) common triggers for an asthma attack in affected individuals. [2 marks]

Answer 28

A) The increased small airway resistance in asthma is due to: inflammation (thickening of airway walls), increased mucus secretion, airway hyper-responsiveness (bronchoconstricion)

B)

i. preventer: Inhaled Corticosteroids- Inhibition of release of immune mediators from macrophages, T-cells and eosinophils. This leads to a reduction of mucus secretion and reduced inflammation.
ii. reliever: Short Acting Beta 2 Agonists (SABAs)- Short term stimulation of beta 2 receptors on smooth muscle lining the bronchioles. Effective in early phase of asthma.

C) Allergens, Smoking, Pollutants, Exercise

Question 29

describe dynamic airway closure and the effects on asthmatic patients

Answer 29

• The small airways close when the pressure in the airways becomes the same as the pleural pressure
• It is a normal process/occurs at low lung volumes in healthy people/occurs during expiration
• In asthma, there is resistance to airflow/reduced airway diameter. This is caused by mucous secretion, inflammation and bronchoconstriction
• This causes a drop-in pressure in the small airways
• Thus, early dynamic small airway closure causes increased residual volume/air trapping/ reduces FVC

Question 30

what is the mechanism of action of a beta-blocker

Answer 30

beta blocker will competitively antagonise the B1 receptors on the heart = slowing the heart rate

Question 31

what is the mechanism of action of calcium channel blocker

Answer 31

reduce the movement of calcium ions into smooth muscle of the vasculature = reduces vasoconstriction = reduces workload and peripheral resistance

Question 32

What are the three different ways in which cytochrome P450 enzyme functions may be affected when multiple drugs are taken?

Answer 32

• Induction of P450 enzyme function by one drug for another
• Inhibition of P450 enzyme function by one drug for another
• Competition for the same P450 enzyme

Question 33

structure and function of endoplasmic reticulum

Answer 33

• Two types: rough and smooth
• Rough is covered in ribosomes important for production of proteins
• Smooth will ship proteins in vesicles to the Golgi complex

Question 34

Purpose of the long cardiac action potentials

Answer 34

Cardiac AP are about 250msec and the resulting muscle contraction is about 160msec. thus, muscle contraction is over by the time cardiac AP comes out of absolute refractory period. The long AP ensures cardiac relaxation between contraction, allowing atria and ventricles to fill. If summation of cardiac muscle occurred, the heart would lose its pump function.