Download Cardiovascular Physiology MCQ`s

Physiology MOCK MCQ exam September 2012
1. Regarding cutaneous circulation which of the following is false:
a. The triple response includes red reaction, wheal and flare
b. Vasoconstriction is caused by sympathetic nerve stimulation
c. Vasodilatation is caused by parasympathetic nerve stimulation
d. Cutaneous blood vessels dilate in the presence of noradrenergic
stimulation during exercise
2. When comparing Foetal red blood cells to maternal red blood cells, foetal
RBCs:
a. Have a greater affinity for 02
b. Stop being produced with HB F as a component after 4 months of age
c. Bind 2,3 DPG less avidly
d. Have a higher 02 content (mg/dl) at the same PO2 (mmHg)
3. Which of the following pressures is incorrectly paired?
a. Aorta in diastole: 80mmHg
b. Right ventricle in systole: 25mmHg
c. Right ventricle in diastole: 5mmHg
d. Left ventricle in diastole: 0mmHg
4. With respect to cerebral circulation, which of the following is false?
a. Autoregulation occurs between 50 – 140mmHg
b. Changes in venous pressure causes a similar change in intracranial
pressure
c. The Kety method is uses inhaled nitrous oxide to measure cerebral
blood flow
d. Hydralazine and ACEI’s reduce the arterial pressure range over which
autoregulation occurs
5. All of the following statements regarding the blood brain barrier are true,
except:
a. It does not restrict the passage of lipid soluble forms of steroid
hormones, water or CO2
b. It has transporters present for choline, amino acids and thyroid
hormones
c. It contains P-glycoprotein which transports analgesics, opioid peptides
and glucose into the blood
d. It has circumventricular organs with fenestrated capillaries in or near
the brain “outside” the barrier
6. Which is true regarding cerebral circulation?
a. The principal arterial supply to the brain is via two external carotid and
two vertebrals
b. The basilar and vertebrals form the circle of Willis
c. Blood flow into the Circle of Willis is distributed almost exclusively to
the ipsilateral side.
d. Venous blood drains principally into the external jugular veins
7. Regarding CSF,
a. Volume is approx 250ml
b. 90% is formed in the choroid plexuses
c. The average normal pressure is about 50mm H2O
d. Absorption of CSF stops below a pressure of about 70mm H2O
8. The following substances penetrate the brain with ease except:
a. Glucose in the presence of GLUT1
b. Protein bound steroids
c. O2 and CO2
d. Water
9. Which best describes the change in intracranial pressure?
a. Cerebral vessels dilate when intracranial pressure rises
b. A rise in venous pressure increases cerebral blood flow
c. If the body is accelerated upwards, arterial pressure at the level of the head
rises
d. If the body is accelerated downwards, intracranial pressure rises
10. Which of the following is incorrect of the blood flow in the coronary vessels?
a. Flow to subendocardial portion of the left ventricle occurs only during
systole
b. Left ventricular coronary flow is increased in tachycardia
c. Coronary flow to atria and RV are reduced during systole
d. Coronary flow is increased when aortic diastolic pressure is low
11. Which of the following causes coronary vasodilation and hence increase coronary
blood flow:
a. Increased levels of CO2, H+, K+
b. Increased lactate and prostaglandins
c. Hypoxia
d. All of the above
12. All are correct regarding neural control of the cardiovascular system EXCEPT:
a. all blood vessels contain smooth muscle and receive sympathetic motor nerve
fibers.
b. Sympathetic noradrenergic fibers end on blood vessels to mediate
vasoconstriction.
c. An increase in neural output from brain stem to sympathetic nerves leads to a
decrease in blood vessel diameter.
d. Stimulation of the vagal innervation to the heart causes a decrease in heart
rate.
13. The RVLM, a major source of excitatory input to sympathetic nerves controlling
the vasculature:
a. Has excitatory inputs from carotid baroreceptors.
b. Has been implicated in essential hypertension.
c. Is located in the pons.
d. Is not affected by hypoxia.
14. Baroreceptors:
a. are located in the intima of the vessels.
b. are stimulated by constriction of the vessels in which they are located.
c. are located in the carotid sinus and the aortic arch.
d. increased baroreceptor discharge excites the tonic discharge of sympathetic
nerves.
15. Which of the following is true of The myogenic theory of autoregulation:
a. Is due to the intrinsic contractile response of skeletal muscle.
b. When vessels are distended the vascular smooth muscle relaxes.
c. May explain the greater degree of contraction at lower pressures.
d. Wall tension is proportional to the distending pressure times the radius of the
vessel (law of Laplace).
16. All of the following cause vasoconstriction EXCEPT
a. Decreased O2 tension
b. Endothelin-1
c. Serotonin
d. Angiotensin II
17. In hypokalemia all of the following are true except:
a. A prominent U wave is present following the T
b. ST segment depression occurs
c. PR interval in shortened to <0.1
d. QT interval remains normal
18. Regarding cardiac muscle which is incorrect:
a. Resting membrane potential is -90mV
b. Gap junctions allow for rapid spread of depolarisation
c. Initial depolarisation is due to influx of K+
d. Ca++ influx through Ica produces the plateau phase
19. Regarding pacemaker cells which is correct:
a. Vagal stimulation increases K+ conductance in nodal tissue
b. Action potentials of SA and AV nodes are largely due to Na+
c. Ca++ has no role in pacemaker action potential
d. Pacemaker potential is only found in the SA and AV nodes
20. Conduction speed in cardiac tissue:
a. Is >6 m/s in the Purkinje system
b. Is slowest in the Bundle of His
c. Is slowest through the SA and AV nodes
d. Is delayed by 0.2s through the AV node
21. Regarding atrial arrhythmias which is incorrect:
a. The atrial rate for flutter is 200-350/min compared with 300-500/min
for fibrillation
b. The most common form of atrial flutter is caused by a large counterclockwise circus movement in the right atrium
c. AV conduction is affected by vagal stimulation but not digitalis
d. Ach release can be stimulated by the occulocardiac reflex
22. Regarding the auscultation of the heart, which is true?
a) A murmur is always pathologic
b) A third heart sound is usually pathologic
c) A fourth heart sound is usually pathologic
d) None of the above
23. Which is correct regarding cardiac output?
a) it decreases in sleep
b) with exercise it can increase no greater than 4x
c) it is calculated as heart rate x afterload
d) it will decrease when standing after lying
24. Regarding stroke volume, choose the correct statement:
a) decreases with systolic dysfunction due to increased end diastolic volume
b) decreases with diastolic dysfunction due to decreased end diastolic volume
c) of the left ventricle is 130ml in a typical individual
d) has a linear relationship to end diastolic volume
25. Which is true of jugular pulsations?
a) the c wave is caused by bulging of the mitral valve during ventricular systole
b) the a wave is caused by ventricular systole
c) the v wave is seen in diastole
d) will be higher in inspiration due to increased thoracic pressure
26. Regarding the O2 consumption of the heart, which is false?
a) at rest it is only about 2mL/100g/min
b) is typically affected more by aortic stenosis than by aortic regurgitation
c) is increased by an increased preload, but decreased by an increased afterload
d) is primarily determined by the heart rate and contractile state of the heart only
27. The v wave of the JVP relates to:
a) the rise in atrial pressure before tricuspid opening
b) atrial systole
c) bulging tricuspid valve in isovolumetric ventricular contraction.
d) aortic valve closure at the end of ventricular systole
28. Which of the following does not increase cardiac output?
a) eating
b) standing from lying position
c) high environmental temperature
d) pregnancy
29. With relation to circulatory changes with exercise which of the following is not
true?
a) dilation of arterioles and pre capillary spinchters increases blood flow 10 –
100 fold
b) a marked increase in stroke volume occurs at the onset of isometric muscle
contraction
c) the average VO2 max for a healthy man is about 38ml/kg/min
d) blood mobilized from reservoirs increases the arterial blood flow by up to
30%
30. In hypovolaemic shock with hemorrhage of 5 - 15mls/kg
a) there will be a decrease in blood pressure
b) the pulse pressure increases with no change in blood pressure
c) there is no change in pulse pressure or blood pressure
d) the rate of discharge of arterial baroreceptors will be unchanged
31. The oxygen consumption of a man during exercise is 5 litres per minute. His
arterial oxygen content is 190mls and venous concentration is 140mls/l. What is his
cardiac output?
a) 25 L/min
b) 5 L/min
c) 15 L/min
d) 10 L/min
32. All of the following are monoamines except:
a. Acetylcholine
b. Serotonin
c. Glutamate
d. Histamine
33. Regarding Acetylcholine receptors which is incorrect:
a. Atropine only blocks muscarinic cholinergic receptors
b. Nicotine receptors are ligand-gated ion channels
c. M2 receptors are found in the pancreas
d. Muscarinic receptors are G-protein coupled receptors
34. Regarding Serotonin which is incorrect:
a. Tryptophan is important for its formation
b. It is inactivated by MAO
c. Most serotonergic receptors are ligand-gated ion channels
d. It is found in platelets and enterochromaffin cells
35. Regarding catecholamines which is correct:
a. Norepinephrine has greatest affinity for α-receptors
b. Catecholamines are synthesised from tryptophan
c. Catecholamine receptors are ligand-gated ion channels
d. Epinephrine has greatest affinity for α-receptors
36. Stimulation of µ-opiate receptor produces all the following except:
a. Constipation
b. Dysphoria
c. Meiosis
d. Respiratory depression
37. Microglia :
a. are derived from macrophages
b. are involved in myelin formation in the CNS
c. are involved in myelin formation in the PNS
d. include oligodendrocytes and Schwann cells
38. A spinal motor neuron is
a. Unipolar
b. Multipolar
c. Bipolar
d. Pseudo-unipolar
39. With regards to Multiple Sclerosis
a. Loss of myelin leads to Na+ leakage.
b. K+ leaks through ligand-gated channels.
c. Disease progression is variable.
d. CSF contains monoclonal bands.
40. Which is incorrectly paired with regards to neuron action potential
a. Resting membrane potential maintenance – Na/K ATPase
b. Depolarization – Na+ channels
c. Repolarization – K+ channels
d. Hyperpolarization – Ca2+ channels
41. Which is incorrectly paired with regards to nerve fiber type
a. A - Pain, cold, touch
b. B – Preganglionic anutonomic
c. C dorsal root – pain, temperature, some mechano-reception.
d. C sympathetic – Post ganglionic sympathetic.
42. The four types of retinal neurons include all of the following except:
a. Bipolar cells
b. Ganglion cells
c. Horizontal cells
d. Paracrine cells
43. The fovea of the eye
a. Has the lowest light threshold
b. Is the region of highest visual acuity
c. Contains both rods and cones
d. Is found over the head of the optic nerve
44. A lesion in an optic tract causes
a. Complete blindness in one eye
b. Homonymous hemianopia (same side of both visual fields)
c. Heteronymous hemianopia (opposite sides of visual fields)
d. Homonymous hemianopia with macula sparing
45. ‘Near response’ of the pupil involves all of the following except
a. Refraction
b. Accommodation
c. Convergence of visual axes
d. Pupillary constriction
46. A patient presents with the following results from a hearing test:
. Weber – sound from vibrating tuning fork localised to right ear
. Schwabach – bone conduction better than normal
. Rinne – vibrations not heard in the air on the right side
Match the following test results with the correct diagnosis of deafness
a.
b.
c.
d.
Conductive deafness in the left ear
Sensorineural deafness in the right ear
Conductive deafness in the right ear
Sensorineural deafness in the left ear
47. With regard to skeletal muscle morphology which of the following is
incorrect?
a. The area between two adjacent M lines is called a sarcomere
b. The thin filaments are made up of actin, tropomyosin and troponin
c. The thick filaments form the A bands
d. The H band is the region where thin filaments do not overlap when
muscle is relaxed
48. All of the following are true except:
a. The resting membrane potential of skeletal muscle is -90mV
b. The resting membrane potential of cardiac muscle cells is -80mV
c. Cardiac muscle is in its absolute refractory period until the potential
reaches about -50mV during repolarization
d. The action potential in skeletal muscle lasts about 6ms
49. Which of the following is incorrectly paired with regard to cardiac muscle
depolarization?
a. Initial rapid depolarization : Opening of voltage-gated sodium channels
b. Prolonged plateau : Opening of voltage-gated T-type calcium channels
c. Initial rapid repolarization : Partly due to closure of sodium channels
d. Final repolarization : Partly due to delayed increase of potassium efflux
50. Type 1 skeletal muscle fibres:
a. Are white
b. Have slow myosin ATPase activity
c. Have high calcium pumping capacity of the sarcoplasmic reticulum
d. Have a large diameter
51. Which of the following regarding Duchenne muscular dystrophy is incorrect?
a. It is X-linked
b. Dystrophin is present but reduced in amount
c. It is usually fatal by the age of 30
d. Becker muscular dystrophy is a milder form of muscular dystrophe
52. The fibre type supplying sensory neurons to Golgi tendon organs are:
a. A alpha
b. A beta
c. A delta
d. Dorsal root C
53. Regarding resting membrane potential it is closest to that of which ion's
equilibrium potential:
a. sodium
b. Calcium
c. chloride
d. potassium
54. Regarding Multiple sclerosis, which is false?
a. it is an autoimmune disease affecting over 3million people
worldwide
b. nerve conduction tests detect increased conduction in motor and
sensory pathways
c. CSF shows presence of oligoclonal bands
d. physiological deficits include muscle weakness, slurred speech,
and bladder dysfunction
55. All of the following are multipolar neurons except:
a. purkinje cell of cerebellum
b. dorsal root gangion cells
c. pyramidal cells of hippocampus
d. spinal cord motor neuron
56. Which of these cells produce myelin in the central nervous system?
a. Scwhann cells
b. fibrous astrocytes
c. microglial cells
d. oligodendrocytes
57. Sensory receptor potentials...
1. are action potentials
2. always bring the membrane potential of a receptor cell toward threshold
3. always bring the membrane potential of a receptor cell away from threshold
4. Are all or none
58. Which reflex is responsible for polysynaptic excitation of contralateral extensors?
a. Stretch reflex (myotatic)
b. Golgi tendon reflex (inverse myotatic)
c. Flexor withdrawal reflex
d. Subliminal occlusion reflex
59. Which of the following is a characteristic of nuclear bag fibres?
a. They are one type of extrafusal muscle fibre
b. they detect dynamic changes in muscle length
c. they give rise to group Ib afferents
d. they are innervated by alpha-motorneurons.
60. Muscle stretch leads to a direct increase in firing rate of which type of nerve?
a. alpha-motor neurons
b. gamma-motor neurons
c. Group Ia fibres
d. Group Ib fibres
61. The impulses coding for vibration sense are carried by the....
a. the dorsal columns of the spinal cord
b. the spinolaminar tract
c. the lateral columns
d. none of the above
62. Slow EPSP’s as seen in autonomic ganglia and cardiac muscles are caused by:
a) Increase in K+ conductance
b) Decrease in K+ conductance
c) Increase in Cl- transport
d) Increase in Ca conductance.
63. Small clear synaptic vesicles contain which of the following?
a) acetylcholine, glycine and GABA
b) Catecholamines, acetylcholine, glutamate
c) acetylcholine, glutamate, neuropeptides
d) glutamate, glycine, calcium
64. Blocking the release of ACH at the neuromuscular junction causes:
a) Spastic paralysis
b) Muscle weakness
c) Flaccid paralysis
d) Increased tone
65. Regarding neuromuscular junctions which of the below is false?
a) The chief transmitter is Acetylcholine
b) Binding of Ach increases Na+ and K+ conductance
c) Acetylcholinesterase is present in high concentration in the
neuromuscular
junction
d) Each nerve fibre ends on multiple end plates
66. Following denervation, which of the following is false?
a) Skeletal and smooth muscle atrophy at similar rates
b) There is a decrease in Nissl substance in the cell body
c) The target muscle becomes hypersensitive to its transmitters
d) There is orthograde and retrograde degeneration
67. The conducting airways are comprised, in order, from largest to smallest:
a. Main bronchi - lobar bronchi - segmental bronchi - terminal bronchioles
b. Lobar bronchi - main bronchi - segmental bronchi - terminal bronchioles
c. Segmental bronchi - lobar bronchi - main bronchi - terminal bronchioles
d. Terminal bronchioles - segmental bronchi - lobar bronchi - main bronchi
68. Regarding the vascular structure of the pulmonary circulation which is true?
a. The path of the arteries, veins and bronchi converge at the periphery of the
lung
b. The arteries form a dense network in the walls of the alveoli
c. The output from the right ventricle is equally divided between the
pulmonary and bronchial circulation
d. Each red blood cell spends about 0.75sec in the capillary network
69. Regarding the respiratory zone of the lung which is true?
a. Gas exchange occurs within the terminal bronchioles
b. Gas exchange within the alveoli is an active process
c. Large pressures are required to move gas through the airway past the
terminal bronchioles
d. The volume of the alveolar space is 2.5-3.0L
70. In terms of blood gas interface which is incorrect?
a. There are about 500 million alveoli
b. Boyles law states that the amount of gas that moves across a sheet of tissue
is proportional to the area of the sheet and inversely proportional to its
thickness
c. The volume of the anatomical dead space is about 150ml
d. The structure of the alveoli maximise gas exchange by generating a large
surface area with a thin barrier to cross
71. Considering removal of inhaled particles which is correct?
a. Inhaled dust particles frequently settle at the level of the respiratory
bronchioles
b. Ciliated cells produce mucus
c. Macrophages remove foreign bodies from the alveoli
d. Nasal hairs are effective at filtering out small dust particles from the upper
airway
72. . Which of the following is incorrect?
The FEV1 is
a) Reduced by an decrease in airway resistance
b) The volume exhaled in the first second
c) Normally 80% of the FVC
d) Reduced by a reduction in elastic recoil of the lung
73. Which of the following is true?
In restrictive lung disease
a) The FEV1 is reduced much more than FVC
b) Inspiration is limited by weakness of the inspiratory muscles
c) Inspiration is limited by increased compliance of the lung
d) The maximum flow rate does not change
74.. Regarding Ventilation-perfusion relationships, which is incorrect?
a) Inequality of ventilation can be measured by a single breath method
b) In the multiple breath method a patient with lung disease would plot a straight
line
c) The alveolar-arterial PO2 difference is an indicator of ventilation-perfusion
mismatch
d) Regional differences of ventilation and blood flow can be measured using
radioactive xenon
75. Which of the following is not a cause of low arterial PO2?
a) hyperventilation
b) diffusion impairment
c) shunt
d) hypoventilation
76. Which of the following is incorrect regarding Blood gases and pH?
a) The pCO2 is a tiny pH meter that uses a bicarbonate buffer
b) A glass electrode is used to measure the pH of whole blood
c) Hypoventilation is always associated with a raised arterial CO2
d) Ventilation-perfusion inequality always causes CO2 retention
77. The following are causes of hypoxaemia EXCEPT:
a.
b.
c.
d.
Hypercapnoea
Hypoventilation
Shunt
Ventilation-perfusion inequality
78. With regards to O2 transport from the air to tissues:
a. PO2 rises as gas moves from the atmosphere to the mitochondria
b. At sea level, PO2 of inspired air is 149 mm Hg (150).
c. PO2 of alveolar gas is determined by a balance between removal of O2
by alveolar ventilation and its continual replenishment by pulmonary
capillary blood.
d. Alveolar PCO2 is normally about 50 mmHg.
79. With regards to shunt, which of the following statements is correct?
a. Shunt refers to blood entering the arterial system after going through
ventilated lung.
b. Hypoxaemia can be abolished by giving 100% O2 to breathe.
c. The O2 concentration of end-capillary blood is usually calculated from
the alveolar PO2 and the O2 dissociation curve.
d. A shunt usually results in a raised PCO2 in arterial blood.
80. The concentration of O2 in any given lung unit is determined by all
EXCEPT:
a.
b.
c.
d.
The ratio of ventilation to blood flow
N2, CO2
Any gas present under steady-state conditions
Functional residual capacity
81. With regards to regional gas exchange in the lung:
a.
b.
c.
d.
Ventilation increases from top to bottom of the lung.
Blood flow increases from the bottom to the top of the lung.
The ventilation-perfusion ratio is highest at the bottom of the lung.
The ventilation-perfusion ratio increases down the lung.
82. Inspiratory muscles include all of the following except
a. Scalene
b. Diaphragm
c. Sternomastoids
d. Internal intercostals
83. Surfactant
a. Is a glycoprotein
b. Is increased in lungs of smokers
c. Helps keep alveoli dry
d. Is produced by type 1 alveolar cells
84. Compliance
a. Is increased by pulmonary fibrosis
b. Is the volume change per unit pressure change
c. Is decreased in emphysema
d. Is greater at higher expanding pressures
85. Regarding airway resistance
a. Turbulent flow occurs at high Reynolds numbers
b. If the radius of a tube is halved, the resistance doubles
c. The Reynolds number is defined as 2rnd/v
d. The major site of resistance are the smaller bronchioles
86. The most important factor limiting flow rate during forced expiration is
a. Compression of the diaphragm
b. Compression of the airways
c. Constriction of bronchial smooth muscle
d. Elasticity of the chest wall
87. Regarding central chemoceptors, which is correct?
a. H+ ions cross the blood brain barrier easily
b. Respond to changes in CO2
c. Are located within the medullary respiration centre
d. Respond to pH changes in the CSF
88. Which of the following is true regarding the respiratory response to oxygen?
a. at a normal pCO2, pO2 can drop significantly without causing increased
ventilation
b. Hypoxaemia stimulates ventilation via it's action on central chemoceptors
c. Raising pCO2 has no effect on ventilation for a given pO2
d. Hypoxia stimulus is important for day to day control of ventilation
89. Lung receptors include all of the following except:
a. Carotid body receptors
b. pulmonary stretch receptors
c. Irritant receptors
d. Bronchial c fibers
90. With regard to peripheral chemoceptors which of the following is correct?
a. The aortic bodies respond to a fall in arterial pH
b. respond to arterial rather than venous pO2
c. Response is slower than seen in central chemoceptors
d. Do not respond to arterial pCO2
91. Regarding the central control of breathing which of the following is false?
a. The dorsal respiratory group is associated with inspiration
b. inspiratory cells are modulated by input from the vagal and accessory
nerves
c. The pneumotaxic centre inhibits inspiration
c. The exploratory centre is quiescent during normal respiration
92. Which of the following is false?
a. Henry’s law states that the amount of dissolved gas is proportional to
the partial pressure
b. The O2 dissociation curve becomes flatter above about 50mmHg
c. Hb is an iron-porphyrin compound joined to four polypeptide chains
d. The deoxygenated form of haemoglobin is in the relaxed state
93. With regards to the O2 dissociation curve, which of the following are correctly
paired?
a. PO2 100mmHg : sats 96%
b. PO2 75mmHg : sats 40%
c. PO2 27mmHg : sats 50%
d. PO2 97.5mmHg : sats 100%
94. Advantages to the shape of the O2 dissociation curve include all of the
following except
a. Loading of O2 is little affected if the PO2 in alveolar gas falls on the
flat upper portion of the curve
b. A large partial pressure between the alveolar gas and blood along the
capillary is greatly lessened due to the red cells taking up O2
c. The steep lower part of the curve means that peripheral tissues can
withdraw large amounts of O2 for a small drop in capillary O2
d. The maintenance of blood PO2 in c. above facilitates diffusion of O2
into tissue cells
95. Which of the following is incorrect?
a. CO has 240 times the affinity of O2 for Hb
b. The CO dissociation curve is almost identical in shape to the CO2
dissociation curve
c. Factors shifting the O2 dissociation curve to the right include increase
H+, PCO2, Temperature and 2,3 DPG
d. Rightward shift of the O2 dissociation curve means more unloading of
O2 at a given PO2
96. Regarding gas transport by the blood:
a. 10% of CO2 is transported as dissolved CO2
b. CO2 is transported mainly in the form of carbamino compounds
c. Reduced Hb binds less CO2 as carbaminohemoglobin than HbO2
d. The PCO2 difference between arterial and mixed venous blood is
typically about 60mmHg
97. Fowler's Method of measuring dead space in the
Lung involves the expiratory measurement of which of the following
a. N2
b. Argon
c. CO2
d. Helium
98. Which volume remains in the lungs after a tidal volume is expired?
a. Vital capacity
b. Expiratory reserve volume
c. Residual volume
d. Functional residual capacity
99. Assuming normal tidal volumes of 500 to 600 mls, what is the normal ratio of
dead space to tidal volume (in the normal lung)?
a. 0.4-0.5
b. 0.2-0.35
c. 0.1-0.2
d. It is impossible to determine an accurate ratio
100. With regards to ventilation, which of the following is true?
a. Fowler's method measures anatomical dead space
b. Bohr's method measures anatomical dead space
c. Bohr's method measures physiological dead space
d. Both A and B are correct
101. When a person is standing, ventilation is....
a. Lowest at the base
b. Highest at the apex due to the effect of gravity
c. Is highest at the base
d. Is uniform through out the lung to due bronchial auto regulation
102. All of the following substances are almost completely removed or
inactivated when passing through the pulmonary circulation except:
a. histamine
b. serotonin
c. Leukotrienes
d. bradykinin
103. Which statement is true about pulmonary vascular resistance?
a. it is normally very high
b. Capillary distention and recruitment decreases pulmonary vascular
resistance
c. Exercise increases pulmonary vascular resistance due to the high blood
flow d. Alveolar hypoxia decreases pulmonary vascular resistance
104. All these drugs act on pulmonary vascular smooth muscle causing an
increase in pulmonary vascular resistance, except:
a. serotonin
b. histamine
c. norepinephrine
d. acetylcholine
105. Regarding hypoxic pulmonary vascular constriction which is false?
a. Endothelin-1 and thromboxane A2 are thought to play a role pulmonary
vascular constriction
b. low blood pH augments hypoxic pulmonary vascular constriction in
presence of alveolar hypoxia
c. pulmonary vascular constriction is mainly due to pulmonary arterial
PO2 rather than alveolar PO2
d. Hypoxic pulmonary vascular constriction is the constriction of
arterioles in a hypoxic region of the lung
106. Other than gas exchange the lung functions include all of the following
except:
a. secretion of immunoglobulins such as Ig A
b. generation of phospholipids such as dipalmitoyle phosphotidylcholine
c. uptake and removal of serotonin
d. conversion of angiotensin II to III
107. Regarding ventilation which of the following is correct?
a. When oxygen consumption is plotted against work rate it increases
non-linearly
b. The liberation of lactic acid increases ventilation
c. During exercise cardiac output increases more rapidly than ventilation
d. The anaerobic threshold is only seen in unfit subjects
108. During exercise which of the following is true?
a. Diffusing capacity increases to a maximum of 2 fold
b. Diffusing capacity increases due to increased blood flow but not to
changes in membrane diffusing capacity
c. The increase in CO is about ¼ the increase in ventilation
d. Pulmonary vascular resistance increases
109. The following changes occur at high altitude, except:
a. Pulmonary vasodilation
b. Hyperventilation
c. Polycythemia
d. Right heart hypertrophy
110. Regarding oxygen toxicity, which of the following is incorrect?
a. High concentrations of oxygen breathed for many hours can damage
the lung
b. High oxygen exposure in premature infants can cause blindness
c. Absorption atelectasis occurs because partial pressure of alveolar gas
greatly exceeds venous blood, causing alveoli to collapse
d. Helium acts as a splint to delay alveolar collapse
111. During diving which of the following is correct?
a. Pressure increases by 2 atmospheres for every 10m descent
b. Increased gas density is responsible for increased work of breathing
c. Nitrogen is highly soluble which is why it can form bubbles in tissues
on descent
d. The risk of decompression sickness can be reduced by breathing
100% oxygen
112. Regarding the rate of diffusion through tissue, which is correct?
a. It is proportional to the square of the surface area
b. It is inversely related to thickness which is only 0.3m in places
c. CO2 diffuses much more rapidly than O2 because it has a lower
molecular weight
d. It is an active process described by Fick’s law
113. Diffusion in the lung can be limited by all of the following except:
a. Exercise
b. Hypoxia
c. Thickening of the blood-gas barrier
d. Low altitude
114. Which is correct regarding gas exchange in the lung:
a. Carbon monoxide rapidly reaches maximum Pco2 in blood so it is
diffusion limited
b. Under normal circumstances oxygen exchange is diffusion limited
c. Because nitrous oxide is highly soluble in blood it is diffusion limited
d. None of the above
115. Using Fick’s law of diffusion through a tissue slice, if gas X is twice as soluble
and 4 times a dense as Y then the ratio of diffusion rates of X to Y will be
a. There will be no difference
b. 0.5
c. 2
d. 8
116. Examples of gases that display perfusion limited exchange in normal individuals
include all except:
a. Oxygen
b. Carbon dioxide
c. Carbon monoxide
d. Nitrous oxide
117. Which part of the nephron absorbs the greatest percentage of water in the
presence of vasopressin?
a. Proximal tubule
b. Descending loop of Henle
c. Distal tubule
d. Collecting duct
118. Which of the following is not actively involved in the micturition reflex?
a. Detrusor muscle
b. Sympathetic nervous system
c. Parasympathetic nervous system
d. External urethral sphincter
119. Which is true regarding cation handling of the kidney?
a. Na+ is actively reabsorbed in the thin descending loop of Henle
b. Acidosis increases K+ secretion
c. K+ secretion is increased by aldosterone
d. The Na+/H+ co-transporter is responsible for Na reabsorption in the
distal convoluted tubule
120. Which is false regarding the counter-current multiplier?
a. The gradient is maintained by the Na-K-2Cl pump
b. Water moves from the ascending to descending limbs of the vasa recta
c. Fluid is hypotonic at the distal end of the ascending limb of the LOH
d. The descending limb of the LOH is permeable to water
121. Regarding the nephron, the following are all correct except:
a. Renin is secreted from the juxtoglomerular cells
b. Principal cells of the collecting ducts are involved in Na reabsorption
c. Mesangial cells help regulate glomerular filtration
d. The macula densa is particularly close to the efferent arteriole
122. Tay Sach’s, a lysosomal storage disease is caused by the loss of an lysosomal
enzyme that catalyses the biodegradation of which of the following substances?
a. phosphatases
b. Collagenase
c. gangliosides
d. None of the above are true
123. Gap junctions...
a. are typically 50 nm wide
b. permit the passage of ions, sugars, amino acids and solutes with MW up to
about 1000
c. allow the passage of small ions only
d. are made up of 10 protein subunits called connexins
124. 99% of the DNA in the mitochondrial genome is derived from which of the
following?
a.
nuclear genes
b.
from Mitochondrial DNA
c.
The mitochondria do not contain a mitochondrial genome
d.
none of the above are true
125. In a cell, most of the ATP is generated by:
a.
the nucleus
b.
the endoplasmic reticulum
c.
the mitochondria
d.
the lysosomes
126. Which is true regarding the Golgi Complex?
a. Can produce ATP
b. Is involved in the breakdown of lipids and proteins
c. Is involved in transcription and translation
d. is involved in the post-translational processing of proteins
127. Increased osmolality of ECF causes:
a. Thirst
b. Decreased water intake
c. Decreased vasopressin secretion
d. Water secretion
128. Stimuli increasing vasopressin secretion include:
a. Increased ECF volume
b. Alcohol
c. Decreased effective osmotic pressure of plasma
d. Nausea and vomiting
129.
With regards to SIADH, which is INCORRECT?
a. Occurs when vasopressin is inappropriately high relative to serum
osmolality
b. Occurs in patients with cerebral disease.
c. Prolonged elevated vasopressin can lead to up-regulation of aquaporin-2
d. Lung tumors and other cancers can secrete vasopressin.
130. Diabetes Insipidus
a. Results when there is a vasopressin deficiency
b. Is classified as Nephrogenic DI when there is insufficient vasopressin
c. is caused by neoplastic lesions of the hypothalamus in 50% of cases
d. Is a disease that develops after surgical removal of the posterior pituitary
is permanent
131.With regards to the renin-angiotensin system:
a. Renin secretion causes a fall in blood pressure
b. Active renin is formed in the juxtaglomerular cells in the kidney
c. Circulating angiotensinogen is decreased by glucocorticoids
d. Angoitensin converting enzyme converts angiotensinogen to angiotensin I
132. The limiting pH of urine is:
a. pH 3.5
b. pH 5.0
c. pH 4.5
d. pH 7.0
133. Regarding ammonia secretion, all of the following are correct except:
a. NH4+ is lipid soluble and diffuses across cell membranes down its
concentration gradient into tubular urine
b. The amount of NH4+ excreted in chronic acidosis at any given urine pH
increases
c. The process of ammonia secretion into urine is called non-ionic
diffusion
d. The ratio of NH3 to NH4+ at pH 7.0 is 1:100
134. All of the following enhance renal acid secretion except:
a. High PCO2
b. Potassium depletion
c. Aldosterone
d. Potassium excess
135. Principle buffers of blood include all of the following except:
a. Bicarbonate
b. Proteins
c. H2PO4
d. Haemoglobin
136. Common sources of extra acid load include all of the following except:
a. Fruits
b. Strenuous exercise
c. Renal failure
d. Ingestion of CaCl2
137. Which of the following cytokines does not promote inflammation?
a. IL-1
b. TNF-
c. TNF-
d. TGF-
138. Which of the following is not part of the acquired immune system?
a. T cells
b. Natural Killer cells
c. B cells
d. Immunoglobulins
139. All of the following are monomers except:
a. IgG
b. IgE
c. IgD
d. IgM
140. Regarding T cells, which of the following statements is CORRECT?
a. T cells are the least common lymphocyte in the blood
b. The majority of T cells express TCR
c. CD4+ cells are involved in the class II MHC pathway
d. Helper type 2 cells (TH2) are predominantly involved in cellular immunity
141. Regarding acquired immunity which of the following statements is CORRECT?
a. Class I MHC expressed by all nucleated cells are important in viral
infection
b. Class II MHC will activate cytotoxic T cells through CD8+ interaction
c. T cells mature into plasma cells which secrete large quantities of
immunoglobulins
d. B memory cells activate T cells for a greater immune response
142. Which of the following is not an action of immunoglobulin’s?
a. Blocking the action of toxins
b. Blocking the attachment of pathogens
c. Opsonisation of pathogens
d. Cleaving C3 -> C3a and C3b through the alternative pathway
143. Regarding immunoglobulins which statement is CORRECT?
a. IgA is the most abundant in plasma
b. IgG and IgM are important in complement activation
c. IgD is important in histamine release
d. IgE is a large pentamer
144. Circulating levels of angiotensinogen are increased by all of the following
except:
a.
Angiotensin II
b.
GLucocorticoids
c.
Thyroid hormones
d.
Insulin
145. Regarding angiotensin
a. Angiotesin III has effective aldosterone stimulating properties
b. Angiotensin II has no direct effect on the adrenal cortex
c. Angiotensin II is twice as potent a vasoconstrictor as norephinephrine
d. It causes dilation of the mesangial cells
146. Renin secretion is increased by all except
a. Sympathetic activity via renal nerves
b. Circulating catecholamines
c. Prostaglandins
d. Vasopressin
147. Natriuretic hormone BNP
a. Causes increased Na reabsorption in the renal tubules
b. Is secreted when the atria are stretched
c. Causes an increase in glomerular filtration rate
d. Is formed only in the heart
148. Regarding vasopressin
a. It is stored in the anterior pituitary
b. It has a half life of 40 minutes
c. Its secretion is not influenced by angiotensin II
d. Its secretion is regulated by osmoreceptors in the hypothalamus.
149. Regarding protein synthesis, which of the following is INCORRECT?
a) Translation is the conversion of information encoded in mRNA to a protein.
b) mRNA attaches to the 60S subunit of the ribosome during protein synthesis
and the polypeptide chain attaches to the 40S subunit.
c) An mRNA chain and its aggregation of ribosomes is called a polyribosome.
d) The order of the amino acids in a peptide chain is called the primary
structure of a protein
150. Translation is
a) The process where mRNA is used as a template for protein production
b) The process of DNA replication prior to cell division
c) The process where DNA wraps around histones to form a nucleosome
d) The process in which a DNA sequence is copied into RNA for gene
expression
151. Regarding glycogen, which is INCORRECT?
a) Major supplies are in the liver and skeletal muscle
b) The process of formation is called glyconeogenesis and breakdown is called
glycogenolysis
c) It is the main storage for glucose in the cell
d) Is produced by the actions of hexokinase on glucose 6-phosphate
152. Fatty acids are broken down in the cell
a) In the mitochondria via B-oxidation
b) In the endoplasmic reticulum via B-oxidation
c) In the mitochondria via deacylation
d) In the endoplasmic reticulum via deacylation
153. Lipoprotein lipase:
a) is located on the gut wall
b) catalyses the breakdown of triglycerides to FFA and glycerol
c) requires thrombin as a co-factor
d) has its activity increased by fasting
154. Regarding cholesterol, which is INCORRECT?
a) Most cholesterol in the liver is discharged as bile
b) Is found only in animals
c) Is synthesized in the liver via HMG-CoA reductase
d) Is an essential constituent of the cell wall
155. Which are NOT transported as part of lipoprotein complexes
a) Cholesterol
b) Triglycerides
c) Phospholipids
d) FFA
156. Which answer is incorrect in regard to composition of body weight in the
average young adult male?
a) 50% protein and related substances
b) 7% Mineral
c) 15% Fats
d) 60% Water
157. Considering metabolic energy production which reaction converts ATP to ADP,
releasing energy?
a) Oxidation
b) Reduction
c) Hydrolysis
d) Phosphorylation
158. Which of the following statements is true?
a) For each pH unit less than 7.0 the [H+] is increased 100 fold
b) For each pH unit less than 7.O the [H+] is increased 10 fold
c) Strong acids and bases dissociate incompletely in water
d) Normal plasma pH in healthy individuals is neutral
159. Diffusion
a) Is an active process
b) occurs when there is a net flux of particles from low to high concentrations
c) tendency magnitude from one area to another is indirectly proportional to
the cross sectional area in which diffusion is taking place
d) means that the particles of a substance dissolved in solvent are in constant
random movement
160. Regarding body fluid composition which is false?
a) Extracellular fluid 20%
b) Blood plasma 30%
c) Interstitial fluid 15%
d) Intracellular fluid 40%
161) Of the following cellular structures which is not involved in protein synthesis?
a)
b)
c)
d)
ribosomes
golgi apparatus
lysosomes
smooth endoplasmic reticulum
162) Regarding apoptosis, which is incorrect?
a) In the CNS, it is a process involved in synapse formation
b) It is when healthy cells are destroyed by external processes such as
inflammation
c) It is when the cell’s own genes play an active role in its demise
d) In epithelia, cells that lose their connections to the basal lamina and
neighbouring cells undergo apoptosis
163) With respect to transport across cell membranes, which is incorrect?
a) Exocytosis is a Ca-dependent process
b) Phagocytosis is an example of endocytosis
c) Facilitated diffusion is when carrier proteins move substances against their
chemical gradient
d) Aquaporins are ion channels selective for transporting water molecules
164) The Na,K,ATPase pump
a)
b)
c)
d)
Catalyzes the hydrolysis of ATP to ADP
Extrudes two Na+ from the cell and takes three K+ into the cell
Transports Na+ and K+ through the alpha subunit
activity is inhibited by digitalis glycosides
165) Which of the following ions has a molecular weight of 69000?
a)
b)
c)
d)
K+
Na+
H20
Albumin
166. Main blood buffers include all of the following except:
a. Carbonic acid
b. Plasma proteins
c. Haemoglobin
d. Phosphate
167. With regards to the response to a metabolic acidosis, which of the following
are incorrectly paired?
a. Buffering: Carbonic acid is converted into H20 and CO2
b. Respiratory response: Prevents limiting pH from being reached
c. Renal response: Excess acid excreted in exchange for Na
d. Clinical features: Fall in pH and fall in pCO2
168. Which of the following statements about renal hydrogen secretion are true?
a. Hydrogen ion secretion in the PCT is independent of tubular sodium
b. ATPase driven proton pump activity is decreased by aldosterone
c. The maximal gradient against which this can occur is at a urine pH=4.5
d. Secretion of H+ ions is mainly via the H,K ATPase pump in the DCT
and CD
169. Renal acid secretion is not increased by:
a. Rising intracellular pCO2
b. Decreased potassium concentration
c. Increased carbonic anhydrase level
d. Decreased aldosterone concentration
170. Which of the following is not a cause of metabolic acid-base derangements?
a. Prolonged vomiting
b. High altitude
c. DKA
d. Ingestion of alkali
171. Regarding renal cell structure and function which statement is false?
.
collecting duct P cells/ principal cells are involved in Na+ and water
reabsorption
a. glomerular filtration allows free passage of small charged substances
up to 4nm diameter
b. the juxta-glomerular apparatus contain cells that secrete renin
c. type I medullary interstitial cells secrete prostaglandins
172. All of the following agents cause relaxation of mesangial cells except:
a. ANP
b. norepinephrine
c. dopamine
d. PGE2
173. Which of the following pairs of transport proteins are matched correctly with
their location within the kidney?
a.
Na/K/2Cl cotransporter : thin descending loop
b.
Na/glucose exchanger: proximal tubule
c.
Na/Cl cotransporter: distal convoluted tubule
d.
Na/H exchanger: collecting duct
174. Which of the following diuretic action is paired incorrectly?
a. mannitol: osmotic diuresis
b. ethanol: inhibits vasopressin secretion
c frusemide: inhibits Na/K/2Cl cotransporter
d. caffiene: inhibits Na/K exchanger
175. Na is primarily reabsorbed in the :
a. proximal tubule
b. thick ascending limb
c. distal convoluted tubule
d. collecting ducts
176. Which of the following is the correct order of segments of the GI tract – from
shortest to longest:
a. Duodenum, oesophagus and stomach, colon, jejunum and ilem
b. Colon, oesophagus and stomach, duodenum, jejunum and ileum
c. Oesophagus and stomach, duodenum, colon, jejunum and ileum
d. Oesophagus and stomach, colon, duodenum, jejunum and ileum
177. Regarding motility of the GI tract, which of the following is correct:
a. If the autonomic input to the gut is removed peristaltic activity will
cease
b. Retrograde cholinergic neurons cause smooth muscle relaxation
c. The basal electrical rhythm is initiated by interstitial cells of Cajal
d. Anterograde cholinergic neurons cause smooth muscle contraction
178. Regarding swallowing, all of the following are true except:
a. It is a reflex response
b. When sitting upright gravity causes food and liquid to fall to lower
oesophagus ahead of the peristaltic wave
c. Efferent nerve fibres are via the trigeminal, glossopharyngeal and
vagus nerves
d. Afferent nerve fibres are integrated in the nucleus of the tractus
solitaries and nucleus ambiguous
179. Regarding gastric emptying which is correct:
a. Fats and acid, but not carbohydrate, in the duodenum inhibit gastric
acid secretion
b. Meals containing fat have the slowest gastric emptying time
c. Meals rich in protein empty faster than those rich in carbohydrate
d. Rate of stomach emptying is independent of osmotic pressure in
material entering duodenum
180. Regarding motility of the small intestine and colon, which is incorrect:
a. The three types of smooth muscle contractions in the small intestine
are peristaltic waves, segmentation contractions and tonic contractions
b. Segmentation contractions are important in increasing chyme exposure
to mucosal surface
c. The colon is the only part of the GI tract where mass action contraction
occurs
d. The gastroileal reflex is when the ileocecal valve constricts in response
to food leaving the stomach
181. Regarding cells is in Islet of Langerhan, which is the correct pairing?
a. A cell: Insulin
b. B cell: Glucagon
c. S cell: Somatostatin
d. F cell: Pancreatic polypeptide
182. Regarding the transporters of glucose
a. The kidney and intestine transport glucose in a potassium-dependant
mechanism
b. GLUT 4 is found on insulin sensitive cells such as skeletal and cardiac
myocytes
c. GLUT 5 is for the absorption of galactose in the intestines
d. Glucose enters cells via GLUT transporters in secondary active transport
183. Insulin causes all of the following except:
a. Rapid transport of glucose, amino acids and potassium into insulinsensitive cells
b. Inhibition of glucagon secretion
c. General increases in cell growth
d. Increased glycogen, protein, and ketone production in the liver
184. Which of the following does not cause an increase in plasma glucose?
a. IGF-1
b. Catecholamines
c. Growth hormone
d. Cortisol
185. Which of the following inhibits insulin secretion?
a. Glucagon
b. Acetylcholine
c. α-adrenergic stimulators
d. β-adrenergic stimulators
186. Which is correct regarding saliva?
a. It is hypertonic compared with plasma
b. 150ml per day is produced from salivary glands
c. Parasympathetic activation is the predominant stimulus for secretion
d. The buffers in saliva help to maintain a pH of 8.0
187. Which gastric cell is correctly paired with its secretion?
a. Hydrochloric acid – chief cell
b. Pepsinogen – parietal cell
c. Intrinsic Factor – chief cell
d. HCO3- -- mucus cell
188. All of the following help regulate pancreatic secretions except:
a. Secretin
b. Trypsin
c. CCK
d. Acetylcholine
189. Bile salts have all of the following properties except:
a. They help increase surface tension
b. They are partly responsible for fat emulsification
c. They are amphipathic and form micelles
d. 95% are reabsorbed from the small intestine
190. Which is NOT true regarding fluid and electrolyte transport in the intestine?
a. Secondary active transport of Na is important in glucose absorption in
the small intestine
b. Sodium crosses the apical membrane in the colon via ENaC similar to
those found in kidney distal tubules
c. Cl- normally enters enterocytes via Na-K-2CL transporters
d. K+ is secreted via the cystic fibrosis transmembrane conductance
regulator
191. The following hormones are primarily concerned with regulation of Ca2+
metabolism EXCEPT:
a. Calcitonin
b. Parathyroid hormone
c. 1,25-Dihydroxycholecalciferol
d. Growth hormone
192. Free serum calcium level is necessary for all EXCEPT:
a. lipid digestion
b. blood coagulation
c. muscle contraction
d. nerve function
193. With regards to phosphate:
a. 75% is found in the skeleton
b. It is found in ATP, cAMP and 2,3-diphosphoglycerate
c. It is not closely regulated
d. 85-90% is passively reabsorbed in the proximal tubule.
194. 1,25-dihydroxycholecalciferol:
a. Stimulates expression of gene products involved in calcium transport.
b. Calibindin-D proteins are found in the kidneys, heart and lungs.
c. Decreases Ca2+ absorption in the intestine.
d. Decreases the synthetic activity of osteoblasts.
195. With regards to PTH:
a. It is synthesized in the parafollicular cells of the parathyroid glands.
b. It is stimulated by low serum PO42-.
c. It causes increased reabsorption of Ca2+ in both the proximal and distal
tubules of the kidneys.
d. It acts indirectly on bone to increase bone resorption.
196. ‘Whorl Cells’ are found in:
a. the zona glomerulosa
b. the zona fasciculata
c. the zona reticularis
d. the Zona accumbens
197. A 46 year old woman presents to your emergency department with hirsutism,
hyperglycemia, obesity, muscle wasting and increased circulating levels of ACTH.
The most likely cause of her symptoms is...?
a. Primary adrenocortical insufficiency (Addison’s disease)
b. Phaeochromocytoma
c. Primary overproduction of ACTH (Cushing’s disease)
d.Treatment with exogenous glucocorticoids
198. Selective destruction of the zona glomerulosa of the adrenal cortex would
produce a deficiency of which hormone?
a. aldosterone
b. androstenedione
c. cortisol
d. dehydroepiandrosterone
199. Which of the following substances is derived from propiomelanocortin
(POMC)?
a. ACTH
b. Melatonin
c. Cortisol
d. Dehydroepiandrosterone
200. Increased adrenocorticotropic hormone (ACTH) secretion would be expected in
patients...
a. with chronic adrenocortical deficiency (Addison’s disease).
b. with primary adrenal hyperplasia
c. who are receiving exogenous glucorticoid drugs for immunosupression post
renal transplant
d. with elevated levels of angiotensin II
201. Which of the below does not affect metabolic rate
a. recent ingestion of food
b. body surface area
c. emotional state
d. dehydration
202. Iron absorption is regulated by all except
a. Rate of iron loss
b. dietary iron intake
c. iron stores in the body
d. state of erythropoiesis
203. Regarding fat digestion
a. Lingual lipase plays a significant role in initial digestion
b. pancreatic lipase is the most important enzyme
c. Colipase is secreted in it's active form
d. Cholesterol Esterase is more active than lipase
204. All of the following are fat soluble vitamins except
a. Vitamin D
b. vitamin B-12
c. Vitamin K
d. Vitamin A
205. The respiratory quotient
a. Is calculated at stead state
b. is affected by hyperventilation
c. Of fat is 0.5
d. Is the same in all organs
206.Regarding physiological effects of thyroid hormones which is incorrect?
a)Increases numbers of beta adrenergic receptors
b)Stimulates lipolysis
c)Formation of HDL receptors
d)Increases protein breakdown
207)Regarding thyroid hormone formation and secretion which is true?
a)T4 has much greater biological activity than T3
b)Minimum daily iodine intake to maintain normal thyroid function in healthy
adults is 1500micrograms
c)Basolateral membranes of thyrocytes contain a sodium/iodine antiporter
d)Thyroglobulin has a molecular weight of 660kDa
208)Considering metabolism and transport of thyroid hormones
a)Most circulating T4 is bound to albumin
b)The half life of thyroxine binding globulin is 5 days
c)T3 and T4 have equal affinities for albumin
d)T4 has a shorter half life then T3
209)Considering regulation of thyroid secretion which of the following is true?
a)TSH is secreted from the hypothalamus
b)Human TSH is a glycoprotein made up of three sub-units
c)hCG can activate thyroid receptors
d)Plasma TSH levels are constant throughout the day
210)Which of the following is incorrect?
a)T4 binds to the nuclei of cells more avidly than T3
b)TSH activates adenyl cyclase via a G- protein linked receptor
c)Thyroid hormones increase red cell 2-3 DPG
d)Dopamine inhibits pituitary TSH secretion