2017 Past Exam

Question 1

Skeletal muscle cells require adenosine triphosphate (ATP) in order to contract. Based on this information, which of the following organelles is found in abundance inside a muscle cell? 
A) Golgi complex
B) smooth endoplasmic reticulum
C) lysosomes
D) rough endoplasmic reticulum
E) mitochondria

Answer 1

?

Question 2

The non-selective uptake of extracellular fluid by a cell is called 
A) pinocytosis
B) receptor-mediated endocytosis
C) exocytosis
D) phagocytosis
E) mitosis

Answer 2

A (pinocytosis)

Question 3

Tetrodotoxin blocks voltage-gated sodium channels. Based on this, which of these would you expect to be DIRECTLY affected by the toxin? 
A) acetylcholinesterase activity
B) action potential propagation
C) spatial summation
D) acetylcholine exocytosis
E) temporal summation

Answer 3

B? (google docs)

Question 4

In a skeletal muscle cell,
A) recruiting more motor units will increase the force of contraction
B) the force of contraction depends on the frequency of action potentials
C) the size of the action potential is proportional to the amount of acetylcholine released
D) adeonosine triphosphate (ATP) binding to a myosin head causes the power stroke
E) acetylcholine is released when calcium ions are released from the sarcoplasmic reticulum

Answer 4

A (google docs)

Question 5

The specificity of hormones is due to
A) secretion from specific cells
B) inactivation of hormones in the kidneys
C) specialization of target-cell receptors
D) specific binding to plasma proteins
E) a direct link up between cells

Answer 5

C

Question 6

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

Answer 6

D?(veins)

Question 7

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

Answer 7

B (The first heart sound occurs when ventricular pressure is greater than atrial pressure)

Question 8

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

Answer 8

D (increased arteriolar vasodilation)- bc sympathetic does vasoconstriction

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 (googledocs) ??

Question 10

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

Answer 10

B (increasing stroke volume)

Question 11

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

Answer 11

B (type I alveolar cells, endothelial cells and the fused basement membranes)

Question 12

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

Answer 12

C (the intra-alveolar pressure is less than atmospheric pressure)

Question 13

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

Answer 13

A? (vital capacity)

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) The binding of CO2 to haemoglobin decreases the ability of O2 to bind to haemoglobin
C) Most CO2 is transported in the blood bound to haemoglobin
D) CO2 binds to the haem component of haemoglobin
E) An increase in PCO2 causes a decrease in H+ in the blood

Answer 14

B

Question 15

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

Answer 15

C (reduces surface tension in alveoli)

Question 16

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

Answer 16

C

Question 17

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

Answer 17

E (reduces the bioavailability of oral drugs)

Question 18

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

Answer 18

A

Question 19

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

Answer 19

B (vasodilation)

Question 20

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

Answer 20

B

Question 21

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

Answer 21

E (asthma)

Question 22

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

Answer 22

D (reaches the circulation)

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) Dose-related toxicity of drug X
B) Drug Y causes induction of a cytochrome P450 enzyme that converts drug X to toxic metabolites
C) Drug X causes irreversible inhibition of a cytochrome P450 by drug X that is responsible for the metabolism of drug Y
D) Drugs X and Y competing for an enzyme that is responsible for their metabolism to inactive metabolites
E) Drug X increasing the absorption of drug Y

Answer 23

A

Question 24

A drop of blood is added to a solution containing 400 mOsm/L of non-penetrating solutes. The osmolarity of red blood cells is 300 mOsm/L. Explain the concept of osmosis.

Answer 24

Osmosis is the movement of water from an area of high water concentration to an area of low water concentration.

Question 25

A drop of blood is added to a solution containing 400 mOsm/L of non-penetrating solutes. The osmolarity of red blood cells is 300 mOsm/L. What will happen to the shape of the red blood cells when placed in this solution?

Answer 25

the cell will shrink?

Question 26

A drop of blood is added to a solution containing 400 mOsm/L of non-penetrating solutes. The osmolarity of red blood cells is 300 mOsm/L. What is the tonicity of this solution when compared to the osmolarity of red blood cells?

Answer 26

hypertonic?

Question 27

Draw a diagram of the intracellular recording of a model action potential. Label the parts with the ions involved and approximate membrane potentials.

Answer 27

?????

Question 28

Define the concept of bulk flow in the cardiovascular system.

Answer 28

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

Question 29

Explain the two forces that influence the direction of bulk flow.

Answer 29

The two forces that influence bulk flow is:

1. capillary hydrostatic pressure:
   - the hydrostatic pressure of blood flowing into capillaries
   - pushes fluid out of capillaries
   - higher at arteriolar end than venular end
2. blood colloid osmotic pressure:
   - plasma proteins too large to exit capillary
   - more solutes in the capillary than the interstitial fluid
   - osmosis draws the fluid back into the capillary

Question 30

(see exam for diagram)
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. List THREE (3) lung function values that can be determined from this graph.

Answer 30

PEF: peak expiratory flow rate
PIF: peak inspiratory flow rate
FVC: forced vital capacity

Question 31

(see exam for diagram)
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. What is the most likely diagnosis for Frank?

Answer 31

emphysema

Question 32

(see exam for diagram)
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. Explain why Frank’s inspiration is different to the normal control.

Answer 32

Emphysema affects both expiration and inspiration as it causes an increase in intrapleural pressure which generates early small airway closure. This changes Frank’s inspiration (increasing it) due to a decrease in elastic recoil. This decrease in elastic recoil is because of the breakdown of elastic fibres in the lung. As inspiration is muscle acting working against elastic recoil, this decrease in elastic recoil means there will be less resistance to expansion of the lungs making inspiration easier and therefore increasing PIF.

Question 33

(see exam for table)
Explain why each of the patients in the table above would be diagnosed with either asthma or chronic obstructive pulmonary disease (COPD)?

Answer 33

???? HELP