A fresh set of 20 random questions is generated every time you open this page and every time you refresh it.For each of the following multiple choice questions, choose the most appropriate answer :
1. Which of the following hormones lowers plasma level of ionized calcium?
A. Calcineurin
B. Calcitonin
C. Parathyroid hormone
D. PTH related peptide
2. Ventricular Depolarization starts from
A. Posterobasal part of ventricle
B. Basal part of ventricle
C. Uppermost part of Interventricular septum
D. Left part of Interventricular septum
3. The cell membrane of skeletal muscle is called the
A. Sarcolemma.
B. Sarcomere.
C. Sarcosome.
D. Sarcoplasmic reticulum.
4. In terms of serum estradiol (E) and progesterone (P), and inhibin, the induction of the preovulatory LH surge is associated with which of the following?
A. High E and low P
B. High E, high P, and high inhibin B
C. Low E and low P
D. Low E and high P
5. Which receptor is directly involved in long- term potentiation?
A. Cholinergic receptors
B. P2 receptor
C. NMDA receptor
D. GABA-B receptor
6. At rest, the tropomyosin molecule is held in place by
A. Actin molecules.
B. Myosin molecules.
C. Troponin molecules.
D. ATP molecules.
7. In the neurons that innervate skeletal muscles, the cytoplasm of the synaptic terminal contains mitochondria and vesicles filled with molecules of the neurotransmitter
A. Epinephrine.
B. Norepinephrine.
C. Acetylcholine.
D. Antidiuretic hormone.
8. The water content of lean body mass is about:
A. 30 ml/100 g
B. 50 ml/100 g
C. 70 ml/100 g
D. highly variable
9. Which of the following regarding the blood- testis barrier is incorrect?
A. It develops before spermatogenesis.
B. Leydig cells are part of the blood-testis barrier.
C. Disruption of the barrier makes spermatogonia prone to immunological attack.
D. All these
10. Which of the following statements is incorrect
A. When sarcomeres are fully shortened, contraction cannot occur
B. When sarcomeres are slightly less than fully shortened, contraction cannot occur
C. Sarcomeres can produce the most tension when stimulated over a relatively wide range of resting lengths
D. When the muscle is fully stretched, contraction cannot occur
11. In glucocorticoid-remediable aldosteronism:
A. angiotensin II has no effect on aldosterone synthesis
B. angiotensin II stimulates whereas angiotensin III inhibits aldosterone synthesis
C. aldosterone synthase is expressed in the zona fasciculata and exquisitely sensitive to stimulation by ACTH.
D. administration of glucocorticoids increases ACTH levels
12. The calcium-binding protein that plays a key role in the regulation of smooth muscle cell contraction is:
A. dystrophin
B. calmodulin
C. troponin C
D. calcineurin
13. ADH circulates in plasma primarily:
A. bound to neurophysin I
B. bound to neurophysin II
C. bound to plasma albumin
D. not bound to plasma proteins
14. The Papez circuit consists of:
A. hypothalamus
B. anterior thalamus
C. cingulate cortex
D. All these
15. The group of chemical messengers whose actions are known to be mediated by receptor tyrosine kinases includes:
A. angiotensin II, ANP and ET 1
B. EDRF, ANP and AVP
C. FSH, LH and GHRH
D. insulin, EGF, IGF 1, PDGF
16. The resting membrane potential of ventricular cardiomyocytes is closest to the equilibrium potential for:
A. sodium
B. chloride
C. potassium
D. calcium
17. Which of the following quantities is dimensionless?
A. Specific gravity of plasma
B. Ejection fraction
C. Filtration fraction
D. All these
18. Which of the following hormones has the highest mineralocorticoid activity?
A. Cortisol
B. Corticosterone
C. Deoxycorticosterone
D. Cortisone
19. Which of the following phenomena is closely associated with slow wave sleep?
A. Dreaming
B. Atonia
C. Sleep walking
D. Irregular heart rate
20. Which of the following events in postsynaptic neuronal membrane underlie excitatory postsynaptic potentials?
A. Opening of Na channels
B. Closure of K channels
C. Opening of calcium channels
D. All these
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