PHSL2101 FINAL EXAM MULTIPLE CHOICE

Blood flow velocity is the slowest in _________ because this is where ________ is greatest

A. Capillaries, cross-sectional area

B. Veins, cross-sectional area

C. Arterioles, resistance

D. Aorta, cross sectional area

E. Capillaries, resistance

A

Pre-load is equivalent to

A. Ventricular end-diastolic volume (EDV)

B. Ventricular end-systolic volume (ESV)

C. Stroke Volume

D. Peak ejection volume

E. Right atrial pressure

A

Which one of the following statements is correct with regard to skin pain system?

A. Strong activation of tactile affecting will not cause a sensation of pain

B. The ipsilateral (same-side) cortical hemisphere processes nociceptive inputs

C. Nociceptive afferent fibres are faster to relay a signal to the spinal cord than the afferents for light touch on the fingers

D. Nociceptive afferents synapse directly on alpha motor neurons to mediate the withdrawal reflex

E. A person with their spinal cord severed at chest level would have paralysed legs but would still feel painful stimuli applied to their feet

A

Key mechanisms in combating orthostatic or postural hypotension include:

A. all of the above.

B. the baroreceptor reflex.

C. muscle pumps.

D. none of the above.

E. reduced distensibility of leg veins compared to thoracic veins.

A

Unlike blood vessels, the lymphatic system:

A. reabsorbs protein and foreign particles from the interstitial fluid.

forms a filtrate which eventually becomes urine.

B. can generate local vasoactive substances.

C. removes damaged erythrocytes from the circulation.

D. has a role in controlling blood pressure.

A

A reflex increase in heart rate may be caused by:

A. all of the above.

B. an increase in right atrial pressure.

C. a decrease in peripheral resistance.

D. an increase in venous return.

E. a decrease in arterial blood pressure.

A

Starling's Law of the Heart means that when ventricular pre-load is increased, stroke volume will

A. stay the same

B. increase

C. decrease

D. decrease momentarily, then increase over time

E. increase momentarily, then decrease over time

B

The repolarisation of pacemaker cells is due in part to:

A. an increase in the permeability of sodium.

B. an increase in the permeability of calcium.

C. an increase in the permeability of potassium.

D. a decrease in the permeability of sodium.

E. a decrease in the permeability of potassium.

C

Which ONE of the following statements about the conduction system of the heart is INCORRECT?

A. Electrical events can spread directly between atria and ventricles through gap junctions.

B. The sinoatrial node is the normal pacemaker of the heart.

C. The atrioventricular node has a slower inherent rate of discharge than the sinoatrial node.

D. Purkinje fibres have the fastest rate of conduction of all parts of the conducting system.

E. The Bundle of His receives impulses from the atrioventricular node.

A

During the rapid ejection phase of the cardiac cycle, which ONE of the following statements is INCORRECT?

A. The ventricular pressure approaches its maximum

B. The mitral valve is closed.

C. The aortic pressure is rising.

D. The ventricular volume is at its lowest.

E. The aortic valve is open.

D

The major mechanism controlling coronary artery diameter is:

A. extracellular CO2 concentration.

B. extracellular K+ concentration.

C. venular constriction.

D. sympathetic nerve activity.

E. accumulation of metabolic waste products.

E

Which ONE of the following statements about an action potential generated from a non-pacemaker cardiac cell is INCORRECT?

A. Repolarisation occurs as a result of inactivation of K+ channels.

B. Depolarisation is initiated by rapid entry of Na+.

C. The resting membrane potential depends to a great extent on the permeability of the cell membrane to K+.

D. The refractory period in ventricular muscle corresponds approximately to the plateau phase of the action potential.

E. The plateau phase of the action potential is associated with a prolonged increase in Ca2+ permeability.

A

Which ONE of the following statements about optical defects is CORRECT?

A. Presbyopia is corrected with a concave lens.

B. Myopia is corrected with a convex lens.

C. Myopia is usually not corrected in adolescent patients.

D. Presbyopia is also called short-sightedness.

E. The prevalence of presbyopia is higher in the over-40 population.

E

Metabolic hyperaemia refers to an increase in blood flow to a tissue or organ caused by:

A. increased local blood pressure.

B. decreased local blood pressure.

C. decreased metabolic activity of the tissue or organ.

D. sympathetic nerve activity.

E. increased metabolic activity of the tissue or organ.

E

Which ONE of the following parameters, when increased, will cause an increase in cardiac stroke volume?

A. afterload

B. end-diastolic volume (EDV)

C. blood pressure

D. end-systolic volume (ESV)

E. peripheral resistance

B

Cardiac stroke volume may be defined as

A. peak ejection pressure minus diastolic pressure

B. pre-load minus afterload

C. end-diastolic volume (EDV) minus end-systolic volume (ESV)

D. afterload minus pre-load

E. end-systolic volume (ESV) minus end-diastolic volume (EDV)

C

Which ONE of the following statements about the mechanical events in the heart is CORRECT?

A. During ventricular ejection, the AV valves are open and the semilunar valves are closed as ventricular pressure is increasing.

B. The dicrotic notch on the aortic pressure wave is seen during the ejection phase.

C. During the ventricular filling phase, ventricular pressure is less than aortic pressure.

D. During the ventricular filling phase, ventricular pressure is greater than atrial pressure.

E. During the ventricular filling phase, all valves in the heart are open.

C

The volume reflex, in which heart rate and renal blood flow are increased following an increase in blood volume, is mediated primarily by:

A. peripheral chemoreceptors

B. aortic baroreceptors

C. atrial and vena cava baroreceptors

D. carotid sinus baroreceptors

E. a combination of atrial and vena cava baroreceptors, aortic baroreceptors and carotid sinus baroreceptors

C

Stimulation of the heart by sympathetic nerves

A. causes bradycardia

B. causes tachycardia

C. results in inhibition the baroreceptor reflex

D. has no effect on cardiac function

E. results in activation of the baroreceptor reflex

B

Blood that leaves the right ventricle and later enters the left ventricle must have passed through which of the following valves?

A. Pulmonary valve only.

B. Pulmonary and bicuspid/mitral valves.

C. Bicuspid/mitral valve only.

D. Aortic and Tricuspid valves.

E. Bicuspid/Mitral and aortic valve

B

If systemic blood pressure falls, the carotid baroreceptors would cause heart rate to ______ and peripheral ________.

A. Increase, vasoconstriction

B. Stay the same, vasoconstriction

C. Decrease, vasodilation

D. Increase, vasodilation

E. Decrease, vasoconstriction

A

Which ONE choice indicates three events that occur at about the same time during the cardiac cycle?

A. semilunar valve closure, second heart sound, ventricular systole.

B. A-V valve closure, first heart sound, ventricular diastole.

C. semilunar valve closure, first heart sound, ventricular diastole.

D. A-V valve closure, second heart sound, ventricular diastole.

E. A-V valve closure, first heart sound, ventricular systole.

E

During which phase of the cardiac cycle are all four heart valves open?

A. all four heart valves are normally never open simultaneously

B. atrial systole

C. ventricular ejection

D. isovolumetric ventricular contraction

E. rapid and reduced filling

A

In cardiac muscle, the action potential in the ventricles:

A. is shorter than the action potential of a pacemaker cell.

B. has a resting membrane potential of about -60mV.

C. has an unstable resting membrane potential.

D. relies on an increase in calcium permeability.

E. is due to an increase in chloride permeability.

D

Which ONE of the following statements is CORRECT with regard to sensory receptors and afferents? Sensory receptors and afferents characterised as "rapidly adapting" or "phasic":

A. generate fewer action potentials during changes in stimulus intensity than during steady stimulation.

B. include some of the types of receptor found in the skin.

C. only generate action potentials when the stimulus changes location.

D. can encode only the intensity of a stimulus.

E. generate action potentials continuously during a steady stimulus.

B

Which ONE of the following statements about an action potential generated from a cardiac muscle cell is CORRECT?

A. The resting membrane potential is about -60 mV.

B. Depolarisation is initiated by rapid entry of Na+.

C. The action potential is shorter than the action potential of a pacemaker cell.

D. Activation of Ca2+ channels is also partly responsible for repolarization.

E. Repolarisation occurs as a result of inactivation of K+ channels.

B

Which ONE of the following is INCORRECT regarding the mechanism by which the substance moves across the wall of a capillary?

A. Glucose is carried across the wall by plasma filtration.

B. Respiratory gases permeate rapidly, because they are lipid soluble.

C. Oxygen permeation is more than 1000 times faster than glucose permeation.

D. Net water transport depends upon net (hydraulic) filtration pressure.

E. Urea diffuses across the wall down its concentration gradient.

A

Adrenaline would increase cardiac output by increasing

A. Heart rate, myocardial contractility and afterload

B. Heart rate only

C. Heart rate and myocardial contractility

D. Afterload only

E. Myocardial contractility only

C

Which ONE of the following statements regarding blood vessels is INCORRECT?

A. The elastic nature of the walls of arteries allows them to act as a pressure reservoir.

B. The contractile activity of smooth muscle cells within arterioles is primarily involved in the control of organ blood flow.

C. The pressure in venules would be less than the pressure in large veins.

D. Capillaries are the vessel type that have the greatest total surface area.

E. Veins function as volume reservoirs due to their high compliance.

C

An increase in myocardial contractility will result in:

A. no change in end-systolic volume or stroke volume.

B. increased end-systolic volume and increased stroke volume.

C. increased end-diastolic volume and increased stroke volume.

D. decreased end-systolic volume and increased stroke volume.

E. decreased end-diastolic volume and decreased stroke volume.

D

The major mechanism(s) controlling the diameter of arteries in the skeletal muscle is

A. extracellular CO2 concentration

B. extracellular K+ concentration

C. all of the above

D. myogenic mechanisms

E. accumulation of metabolic waste products

C

According to Poiseuille's equation, blood flow in a vessel would be reduced by half when:

A. blood flow velocity is doubled.

B. the pressure gradient along the length of vessel is doubled.

C. vessel diameter is halved.

D. blood viscosity is halved.

E. vessel length is doubled.

E

Which ONE of the following statements is INCORRECT? Increased sympathetic nervous system activity to the sinoatrial node:

A. results in a less negative membrane potential at the end of repolarisation.

B. increases the frequency of action potentials generated.

C. causes an increase in heart rate.

D. decreases the slope of the spontaneous depolarisation of these action potentials.

E. allows threshold to be reached more quickly.

D

Which ONE of the following is true of the ventricular filling phase of the cardiac cycle?

A. All valves in the heart are open.

B. Ventricular pressure is increasing.

C. Ventricular pressure is less than aortic pressure.

D. Ventricular filling occurs during systole.

E. Ventricular pressure is greater than atrial pressure.

C

What is occurring during ventricular ejection?

A. The AV valves are closed and the semilunar valves are open as blood is leaving the ventricles.

B. The AV and semilunar valves are open as blood is leaving the ventricles.

C. The AV and semilunar valves are closed as ventricular pressure is increasing.

D. The AV valves are open and the semilunar valves are closed as blood is leaving the ventricles.

E. The AV valves are open and the semilunar valves are closed as ventricular pressure is increasing.

A

Which ONE of the following would NOT result in an increase in the movement of fluid out of capillaries?

A. An increase in blood pressure within the capillary.

B. A decrease in colloid osmotic pressure of the plasma.

C. None of the above.

D. A decrease in interstitial fluid pressure.

E. A decrease in the osmotic pressure of the interstitial fluid.

E

A patient absorbs 300ml/min of oxygen. The oxygen content of blood taken from the femoral artery = 18ml/100ml and blood taken from the pulmonary artery has an oxygen content of 13ml/100ml. If the patient has a heart rate of 60 beats/min, the patient's stroke volume is:

A. 100ml.

B. 12ml.

C. 10ml.

D. 80 ml.

E. 120ml.

A

According to Fick's law, which ONE of the following would NOT be a factor in diffusion of a substance across the capillary wall?

A. The total surface area of the capillary wall

B. Hydrostatic (blood) pressure in the capillary

C. The molecular weight of the substance

D. The plasma concentration of the substance

E. The concentration of the substance in the interstitial fluid

B

The decrease in blood pressure is greatest across _________ because this is where is highest __________

A. veins, cross-sectional area

B. capillaries, cross-sectional area

C. arterioles, resistance

D. aorta, cross-sectional area

E. capillaries, resistance

C

A patient absorbs 350 ml/min of oxygen. The oxygen content of blood taken from the femoral artery = 16ml/100ml and blood taken from the pulmonary artery has an oxygen content of 11ml/100ml. If the patient has a heart rate of 70 beats/min, the patient's stroke volume is:

A. 10 ml

B. 12 ml

C. 120 ml

D. 100 ml

E. 80 ml

D

Cardiac stroke volume may be defined as

A. pre-load minus afterload

B. end-diastolic volume (EDV) minus end-systolic volume (ESV)

C. afterload minus pre-load

D. peak ejection pressure minus diastolic pressure

E. end-systolic volume (ESV) minus end-diastolic volume (EDV)

B

Myogenic mechanisms involved in autoregulation of blood flow are activated by:

A. the [O2] in surrounding tissue.

B. altered intra-luminal blood pressure.

C. the [K+] in surrounding tissue.

D. generation of local vasoactive substances.

E. endothelium-derived vasoactive factors.

B

Which ONE of the following statements about an action potential generated from a sinus nodal fibre is INCORRECT?

A. The unstable baseline can be partly attributable to a progressive decrease in Ca2+ permeability.

B. The resting membrane potential is about -60 mV.

C. Repolarisation is in part due to activation of K+ channels.

D. The sudden upstroke (depolarisation) is due to the opening of Ca2+ channels causing a rapid influx of Ca2+ into the cell.

E. The unstable baseline can be partly attributable to a progressive spontaneous reduction in membrane permeability to K+.

A

Which ONE of the following statements about an action potential generated from a sinus nodal fibre is CORRECT?

A. The resting membrane potential is about -90 mV.

B. Once threshold is reached, there is a sudden increase in internal potential due to the opening of Na+ channels.

C. The unstable baseline can be partly attributable to a progressive decrease in Ca2+ permeability.

D. The duration of the action potential is about 300 msec.

E. The repolarisation of pacemaker cells is due in part to an increase in the permeability of potassium.

E

According to Poiseuille's equation, reducing a blood vessel's diameter by 20% would reduce blood flow in the vessel by (approximately):

A. 80%

B. 60%

C. 50%

D. 40%

E. 20%

B

Which ONE of the following organs/tissues receives the greatest increase in systemic blood flow during exercise?

A. Brain.

B. Kidneys.

C. Heart.

D. Skin.

E. Muscle.

E

The greatest proportion of blood volume is present within which ONE of the following vessel types?

A. Systemic capillaries

B. Heart

C. Systemic arteries and arterioles

D. Pulmonary blood vessels

E. Systemic veins and venules

E

In healthy endothelial cells, arachidonic acid is converted to --------- which ---------- formation of blood clots.

A. Nitric oxide: inhibits

B. Thromboxane A2: stimulates

C. Prostacyclin: inhibits

D. Thromboxane A2: inhibits

E. Prostacyclin: stimulates

C

Which ONE of the following statements about haemostasis is CORRECT?

A. Vitamin D is important for the production of five important clotting factors, including prothrombin.

B. Immediately after a blood vessel is cut or ruptured the wall of the vessel dilates.

C. Prothrombin activator catalyses the conversion of fibrinogen into long fibrin fibres.

D. Calcium ions are required for several steps of the prothrombin activation cascade.

E. Thromboxane A2 is released by damaged vessel walls to initiate vasoconstriction.

D

With regard to image formation by the eye:

A. the cornea and lens are concave lenses.

B. myopia is a condition in which the image of a distant object is formed in front of the retina.

C. the retinal image is an upright image of the object.

D. the cornea has lower optical power than the lens.

E. the focal point of the eye lies between the cornea and the lens.

B

Pernicious anaemia is associated with which ONE of the following?

A. Bleeding

B. Insufficient Vitamin B12

C. Inadequate bilirubin levels

D. Damage to the bone marrow

E. Abnormal haemoglobin

B

Which ONE of the following statements about haemoglobin is INCORRECT?

A. Haemoglobin is an excellent acid-base buffer because the iron binds bicarbonate.

B. Each of the subunits of the haemoglobin molecule contains a haem group that is necessary for the binding of oxygen.

C. Males have a haemoglobin concentration of around 16 g per 100 ml of whole blood and females around 14 g per 100 ml of whole blood.

D. Haemoglobin from erythrocytes that have been removed from the circulation is degraded into bilirubin and other compounds.

E. The human erythrocyte contains haemoglobin, a respiratory pigment based on the iron atom.

A

Which ONE of the following statements is INCORRECT? Neutrophils:

A. are one type of granulocyte.

B. are derived from committed myeloid cells in the bone marrow.

C. make up the majority of white blood cells.

D. generally have single large non-segmented nuclei.

E. are chemotaxic.

D

Which ONE of the following triggers erythropoietin release?

A. Damage to a blood vessel wall and subsequent exposure to collagen

B. Increased blood CO2 levels

C. Decreased blood oxygen levels

D. Infection in the blood

E. Infection in the tissues

C

According to the Starling Equation concerning water movements across the capillary wall, constriction of arteries leading into a capillary bed would

A. decrease the net filtration pressure in the capillaries.

B. not alter the net filtration pressure in the capillaries.

C. increase the net filtration pressure in the capillaries.

D. not alter the net filtration pressure in the capillaries but increase water outflow.

E. not alter the net filtration pressure in the capillaries but increase water inflow.

A

The main site of haematopoiesis in the fetus from the second to the seventh month is the:

A. Bone marrow

B. Kidney

C. Yolk sac

D. Liver

E. Spleen

D

Choose the ONE CORRECT statement. The vestibular system:

A. the semi-circular canals to detect linear acceleration.

B. would not generate any useful signals in a zero-gravity environment.

C. uses hair cells to convert an electrical potential to mechanical energy.

D. provides information that goes to motor reflexes and to cortex.

E. uses the utricle and saccule to provide information about head rotation.

D

Which ONE of the following statements about haemostasis is CORRECT?

A. Thromboxane A2 is released by damaged vessel walls to initiate vasoconstriction.

B. The intrinsic pathway is initiated by the activation of factor X.

C. The extrinsic pathway is initiated by the release of factor III from damaged tissue to complex with factor VII and V.

D. The formation of a platelet plug is inhibited by healthy endothelium through the release of ADP.

E. Prothrombin is the enzyme that catalyses the conversion of fibrinogen into long fibrin fibres.

C

Which ONE of the following statements about erythropoietin is CORRECT?

A. is a hormone produced only in the liver.

B. Increased levels of erythropoietin result in increased circulating levels of red blood cells within 24 hours.

C. Erythropoietin stimulates the production of proerythroblasts from the bone marrow.

D. Testosterone reduces the basal rate of erythropoiesis.

E. Hypoxia causes a marked decrease in erythropoietin levels.

C

The human erythrocyte:

A. has a diameter of about 15 micrometres.

B. develops from a committed myeloid stem cell.

C. lives on average for 280 days.

D. uses the enzyme carbonic anhydrase to catalyse the reaction between carbon and oxygen.

E. contains 75% haemoglobin.

B

The first step of haemostasis is:

A. the formation of a platelet plug.

B. secretion of histamine.

C. the formation of a blood clot.

D. vascular spasm.

E. the formation of a fibrin clot.

D

Which type of leukocyte defends against parasitic infections?

A. Monocytes

B. Eosinophils

C. Erythrocytes

D. Lymphocytes

E. Neutrophils

B

With regard to the organisation of somatosensory cortex:

A. The cortical area allocated to touch for the wrist is larger than that allocated to touch for the thumb.

B. The cortical representation of touch for the right hand is found in the right somatosensory cortex.

C. The cortical representation of the hand is found near that of the face.

D. The cortical representation of the hip lies between the representations of the foot and knee.

E. The cortical representation of temperature sense in the right hand is located in the opposite hemisphere to the cortical representation of touch in the right hand.

C

Which ONE of the following statements about iron metabolism in humans is CORRECT?

A. About 50% of ingested iron is absorbed into the body each day.

B. Vitamin C can increase iron absorption by oxidizing ferrous ions to ferric ions.

C. Free iron will bind with apotransferrin to form transferrin, which can then be transported in the blood.

D. Phosphates form soluble compounds with ingested iron aiding iron absorption.

E. The total quantity of iron in the body is about 20 g.

C

Which ONE of the following statements about optical defects is CORRECT?

A. Hyperopia is usually not corrected in adolescent patients.

B. Myopia is corrected with a convex lens.

C. Presbyopia is also called short-sightedness.

D. The prevalence of myopia is higher in the over-40 population.

D. Presbyopia is corrected with a concave lens.

A

Which of the following sensory parameters are topographically organised in their primary sensory cortex?

Visual Cortex, Somatosensory Cortex, Auditory Cortex

A. Colour, Touch Intensity, Loudness

B. Stimulus location, Stimulus location, Pitch

C. Colour, Stimulus location, Loudness

D. Stimulus location, Touch Intensity, Loudness

E. Colour, Stimulus location, Pitch

B

A person who is unable to see things to the left side of where their gaze is directed has probably suffered damage to:

A. their right optic nerve before the optic chiasm.

B. their left optic nerve after the optic chiasm.

C. their right visual cortex (occipital lobe).

D. their left eye.

E. their left visual thalamus (lateral geniculate nucleus).

C

In the myotatic reflex:

A. the 1A afferents increase their firing rate in response to increased muscle tension.

B. the 1B afferents increase their firing rate in response to increased muscle length.

C. the intrafusal muscle fibres contract due to 1B activity.

D. the extrafusal muscle fibres relax due to 1A activity.

E. the extrafusal muscle fibres contract due to 1A activity.

E

Which ONE of the following statements about the photoreceptors of the retina is CORRECT?

A. The highest density of photoreceptors in the eye is at the optic disc.

B. Both rods and cones are found in the centre of the visual field.

C. In the peripheral retina, rods are more common than cones.

D. There are more cones than rods in the retina.

E. There are three types of rod photoreceptors and one type of cone photoreceptor.

C

Shown in A and B are the action potentials generated in a single tactile afferent over 1s, under two different conditions. The alteration in response from A to B is due to a change in the applied stimulus.

The stimulus change that best accounts for the response change from A to B is:

A. making the stimulus surface contact the skin with less force.

B. increasing the temperature of the stimulus surface that contacts the skin.

C. moving the stimulus surface more quickly across the skin.

D. making the stimulus surface contact the skin over a larger area.

E. making the stimulus surface contact the skin for less time.

A

Which ONE of the following statements about human leucocytes is CORRECT?

A. Neutrophils generally have single large non-segmented nuclei.

B. Eosinophils are one type of agranulocyte.

C. Lymphocytes are the largest of all the white blood cells in humans.

D. Neutrophils make up the majority of white blood cells.

E. The main function of neutrophils is to defend against parasitic infections.

D

Which ONE of the following statements is CORRECT with regard to the skin pain system?

A. The ipsilateral (same-side) cortical hemisphere processes nociceptive inputs.

B. Nociceptive afferent fibres are slower to relay a signal to the spinal cord than the afferents for light touch on the fingers.

C. Nociceptive afferents synapse directly on alpha motor neurons to mediate the withdrawal reflex.

D. Strong activation of tactile afferents will cause a sensation of pain.

E. A person with their spinal cord severed at chest level would have paralysed legs but would still feel painful stimuli applied to their feet.

B

The blood-brain barrier:

A. is a semi-permeable membrane that encases the brain and cerebro-spinal fluid.

B. prevents all drugs from reaching the brain.

C. is permeable to both red blood cells and white blood cells.

D. is permeable to most small polar molecules.

E. is produced by astrocytes and endothelial cells of the capillary wall.

E

Which ONE of the following statements about the structure of the brain is CORRECT?

A. The grey matter of spinal cord is organised as a thin sheet of neurons.

B. The layers of cortex run perpendicular to the cortical surface.

C. The corpus callosum is a grey matter structure.

D. Connections between cortical areas are made by white matter tracts.

E. The ventricles are formed by axons.

D

Three neurons (designated N1, N2 and N3) synapse onto a common post-synaptic neuron. Simultaneous synaptic activity in these neurons has the following effects:

N1 and N2: post-synaptic action potential

N2: post-synaptic action potential

N2 and N3: no post-synaptic action potential

Which of the following is the most likely conclusion?

A. N1 is inhibitory, N2 is sub-threshold excitatory, N3 is sub-threshold excitatory.

B. N1 is sub-threshold excitatory, N2 is sub-threshold excitatory, N3 is inhibitory.

C. N1 is supra-threshold excitatory, N2 is sub-threshold excitatory, N3 is inhibitory.

D. N1 is sub-threshold excitatory, N2 is supra-threshold excitatory, N3 is inhibitory.

E. N1 is inhibitory, N2 is supra-threshold excitatory, N3 is sub-threshold excitatory.

D

Which ONE of the following statements about haemostasis is CORRECT?

A. The extrinsic pathway is initiated by the activation of factor XII.

B. The formation of a platelet plug is inhibited by healthy endothelium through the release of ADP.

C. Thrombin is the enzyme that catalyses the conversion of fibrinogen into long fibrin fibres.

D. Thromboxane A2 is released by damaged vessel walls to initiate vasoconstriction.

E. The intrinsic pathway is initiated by the activation of factor X.

C?

Which ONE of the following statements is CORRECT with regard to sensory receptors and afferents? Sensory receptors and afferents characterised as "rapidly adapting" or "phasic":

A. generate more action potentials during changes in stimulus intensity than during steady stimulation.

B. only generate action potentials when the stimulus changes location.

C. generate action potentials continuously during a steady stimulus.

D. include the type of receptor used to encode joint angle.

E. can encode only the intensity of a stimulus.

A

Which ONE of the following statements about the spinal cord is INCORRECT?

A. The ventral horn of the spinal cord contains motor neurons.

B. A dermatome refers to the region of skin innervated by a single spinal nerve.

C. The spinal nerves have an organization where the sacral nerves tend to innervate the face, and the cervical nerves innervate the legs.

D. The spinal nerves are formed from the fusion of the dorsal and ventral root.

E. The spinal nerves may fuse and join on their way to innervate their target zone

C

Tactile sensory fibres with large receptive fields:

A. have a large area of cortex dedicated to processing their input.

B. are found in body regions with small two-point discrimination thresholds.

C. permit precise localization of the site of a tactile stimulus.

D. do not have topographically-organised projections.

E. innervate body regions with low receptor densities.

E

When a neuron adapts to a stimulus, this means that it:

A. changes its morphology to accommodate the stimulus.

B. generates action potentials at a lower rate.

C. generates stronger action potentials.

D. becomes more selective for the properties of that stimulus.

E. becomes sensitised to the stimulus.

B

Inhibitory synapses from a GABA-ergic neuron:

A. depolarise the post-synaptic neuron membrane potential towards 0 mV.

B. can prevent the post-synaptic neuron from reaching threshold.

C. are not found on neurons that also receive excitatory input.

D. play an important role in synaptic transmission at the vertebrate neuromuscular junction.

E. cause IPSPs that do not interact with EPSPs in the same post-synaptic neuron.

B

Choose the CORRECT statement. The vestibular system:

A. would not generate any useful signals in a zero-gravity environment.

B. uses the utricle and saccule to provide information about static head position.

C. uses the semi-circular canals to detect linear acceleration.

D. uses hair cells to convert an electrical potential to mechanical energy.

E. provides reflex information that does not go to the cortex.

B

Golgi tendon organs:

A. are rapidly adapting receptors.

B. cause mono-synaptic excitation of alpha motoneurons.

C. respond primarily to muscle length.

D. are in series with extrafusal muscle fibres.

E. are in parallel with intrafusal muscle fibres.

D

A person with normal vision except for anomalous trichromacy (red-green colour-blindness):

A. has blurry vision.

B. sees purple as grey.

C. sees yellow as blue.

D. sees red and green as grey.

E. sees blue as grey.

B

During normal voluntary muscle contraction (alpha and gamma co-activation):

A. extrafusal muscle fibres shorten while intrafusal fibres do not.

B. intrafusal muscle fibres shorten while extrafusal fibres do not.

C. extrafusal fibres provide most of the contractile force.

D. gamma motor neurons activate the alpha motor neurons.

E. contraction of the intrafusal muscle fibres weakens the stretch reflex.

C

With regard to the vestibular senses:

A. The semi-circular canals can signal the direction of gravitational acceleration.

B. The semi-circular canals use small rocks to help detect inertia.

C. The semi-circular canals can signal linear acceleration without significant adaptation.

D. The otolith organs can signal linear acceleration without significant adaptation.

E. The otolith organs can signal the direction of a steady velocity.

D

In transducing mechanical energy into a neural signal, the cochlear hair cells:

A. have the same response to a forwards deflection of the stereocilia as to a backwards deflection.

B. utilise an influx of cations to depolarise the hair cell.

C. employ stereocilia that allow a single hair cell to combine the sound signals from the two ears.

D. utilise ligand-gated channels near the apical border of the cell.

E. receive a chemical signal from the tectorial membrane.

B

With regard to spinal motor neurons:

A. A single action potential in a single alpha motor neuron does not cause muscle contraction.

B. The activity of an alpha motor neuron can be influenced by descending cortical input.

C. A motor unit may be composed of more than one alpha motor neuron.

D. A motor unit is composed of an alpha motor neuron and a single muscle fibre.

E. Alpha motor neurons synapse onto spindle afferent neurons.

B

With regard to spinal motor neurons:

A. A single action potential in a single alpha motor neuron does not cause muscle contraction.

B. Alpha motor neurons synapse onto spindle afferent neurons.

C. A motor unit may be composed of more than one alpha motor neuron..

D. The activity of a gamma motor neuron can be influenced by descending cortical input.

E. A motor unit is composed of an alpha motor neuron and a single muscle fibre.

D

Reflexes:

A. must take less than 10ms otherwise they are not involuntary.

B. must involve a proprioceptive afferent such as a Golgi tendon afferent.

C. can be used to keep a limb in position.

D. are not signalled to the cortex.

E. require only an integrator and an effector.

C

The human erythrocyte:

A. contains 30% haemoglobin.

B. uses the enzyme carbonic anhydrase to catalyse the reaction between carbon and oxygen.

C. lives on average for 250 days.

D. has a diameter of about 15 micrometres.

E. develops from a committed lymphoid stem cell.

A

Choose the option that correctly assigns the roles of the outer, middle and inner ear.

A. outer ear: impedance matching, middle ear: modify sound based on location of source, inner ear: sound transduction.

B. outer ear: modify sound based on location of source, middle ear: sound transduction, inner ear: impedance matching.

C. outer ear: modify sound based on location of source, middle ear: impedance matching, inner ear: sound transduction.

D. outer ear: impedance matching, middle ear: sound transduction, inner ear: modify sound based on location of source.

E. outer ear: sound transduction, middle ear: impedance matching, inner ear: modify sound based on location of source transduction.

C

Which ONE of the following statements about motor pathways is CORRECT?

A. The corticospinal tract originates mainly in the basal ganglia.

B. The extrapyramidal tracts are predominantly involved in control of limb muscles.

C. The corticospinal tract crosses the midline.

D. The extrapyramidal tracts synapse onto spinal motor neurons.

E. The corticospinal tract carries afferent information.

C

Choose the CORRECT statement about the retina.

A. Increased light intensity causes increased transmitter release from photoreceptors.

B. Rod photoreceptor activity is unaffected by a change in the intensity of a coloured stimulus.

C. Rod photoreceptors outnumber cone photoreceptors throughout the retina except at the fovea.

D. Stimulus colour is coded by the activity of rod photoreceptors.

E. Stimulus location is coded by the type of photoreceptor activated.

C

Which ONE of the following statements about the functional organization of the brain is CORRECT?

A. The limbic system is a group of brain areas primarily related to motor control.

B. The thalamus is a single nucleus with inputs from sensory receptors or motor areas.

C. There is a specialised region of cortex for vision at the back of the brain.

D. The left cortical hemisphere generally controls the left side of the body.

E. Sensory systems are usually restricted to one level of the brain e.g. brain stem

C

In response to an increase in arterial blood pressure, the baroreceptor reflex would cause

A. bradycardia and peripheral vasodilation.

B. tachycardia and peripheral vasoconstriction.

C. bradycardia and peripheral venoconstriction.

D. tachycardia and peripheral vasodilation.

E. bradycardia and peripheral vasoconstriction.

A

Which ONE of the following statements about cerebro-spinal fluid (CSF) is CORRECT?

A. CSF has a higher K+ concentration than Na+ concentration.

B. CSF is made at the choroid plexus.

C. The volume of CSF in a normal individual is approximately the same as the volume of plasma.

D. CSF contains the same white blood cell count as blood, but no red blood cells.

E. CSF is found both inside and outside the meninges.

B

Which ONE of the following statements is CORRECT with regard to the organisation of the spinal cord and peripheral nervous system?

A. A dermatome is innervated from multiple levels of spinal nerves.

B. Efferent fibres take information from the periphery to the central nervous system.

C. The spinal cord has a core of white matter surrounded by grey matter.

D. Ventral roots contain mainly afferent fibres.

E. Dorsal root ganglia contain the soma of sensory neurons.

E