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. Worldwide, the commonest preventable cause of mental retardation in the newborn is:
A. iodine deficiency
B. phenylalanine hydroxylase deficiency
C. cystic fibrosis
D. urea cycle defect
2. Which of the following events in postsynaptic neuronal membrane underlie inhibitory postsynaptic potentials? Opening of:
A. Na channels
B. Ca channels
C. Cl channels
D. All these
3. Which of the following defines the pressure in the vascular system in the absence of blood flow?
A. Pulse pressure
B. Critical closing pressure
C. Mean circulatory pressure
D. Perfusion pressure
4. The smallest amount of muscle that can contract in response to excitation of a single motor neuron is:
A. 1 muscle fiber
B. a muscle fasciculus
C. the entire muscle
D. all muscle fibers supplied by that neuron
5. The osmolar concentration of sodium in normal human plasma is approximately:
A. 275 - 295 mOsm/L
B. 135 - 145 mOsm/L
C. 240 - 250 mOsm/L
D. 95 - 110 mOsm/L
6. During hip replacement, loss of joint and ligament receptors leads to
A. No loss of sensation
B. Loss of all sensations
C. Joint sensation lost in stable position
D. Decrease in movements and decrease in sensation
7. The most abundant protein in mammalian cells is:
A. actin
B. collagen
C. titin
D. dystrophin
8. Which of the following is absent in decorticate animals?
A. Gross movements
B. Temperature regulation
C. Hopping and placing reaction
D. Vestibulo-ocular reflex
9. Gamma oscillations in EEG, which occur when an individual is aroused and focuses attention on something, occur at a frequency of:
A. 0-0.4 Hz
B. 4-7 Hz
C. 0-12 Hz
D. 30-80 Hz
10. Of the following substances, the lipid bilayer per se (i.e., without proteins) is most permeable to:
A. sodium ions
B. urea
C. glucose
D. water
11. The relation between the magnitude of sensation and stimulus intensity is given by the:
A. law of specific nerve energies
B. labeled line principle
C. Weber-Fechner law
D. law of projection
12. IPSPs due to chloride influx are produced by:
A. acetylcholine
B. GABA
C. glycine
D. B and C
13. The resting membrane potential of ventricular cardiomyocytes is closest to the equilibrium potential for:
A. sodium
B. chloride
C. potassium
D. calcium
14. Athletes usually go through a "warm-up" period before engaging in an event. The reason for this "warm-up" period would be to take advantage of
A. Incomplete tetanus.
B. Complete tetanus.
C. Treppe.
D. Wave summation.
15. Which of the following is an example of a ligand-gated ion channel?
A. Nicotinic Ach receptor (nAchR)
B. Beta-2 adrenergic receptor
C. 5 HT receptor
D. Histamine 2 receptor
16. In the stretch reflex, relaxation of antagonist muscles is due to:
A. reciprocal innervation
B. presynaptic inhibition
C. Ia fiber stimulation
D. antidromic conduction
17. The principal estrogen secreted by the fetoplacental unit is:
A. estriol (E3)
B. estradiol (E2)
C. estrone (E1)
D. All these
18. The [H+] of arterial plasma is normally about:
A. 20 nmol/L
B. 30 nmol/L
C. 40 nmol/L
D. 50 nmol/L
19. Feedforward inhibition has been well described in neural circuits in the:
A. spinal cord
B. cerebellum
C. stretch reflexes
D. nociceptive pathway
20. Gastric emptying is slowest after a meal containing:
A. fat
B. carbohydrate
C. protein
D. indigestible fiber
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