original University of Ibadan (UI) Physiology
Questions and Answers below for your practice. We discovered 203 repeated questions from 2008 to 2016. Read it below and download your complete copy now.
This includes past MCQs in physiology exams administered to students of the following departments in the UI college of medicine
1. Medicine & Surgery
6. Human Nutrition
7. Nursing Science
1. Which of the following is an example of primary active transport?
a. Na+ – H+ exchanges
b. Na+ – Ca2+ exchange
c. The Na+/K+ ATPase
d. Cl—HCO3- exchange
e. None of the above
Correct Answer: The Na+/K+ ATPase
• The Na+/ K+ ATPase is the sodium pump and exchanges 3 intracellular Na+ for 2 extracellular K+ each molecule of ATP hydrolyzed
• Na+-H+ exchange and Na+-Ca2+ exchange are examples of secondary active transport
• Cl–HCO3- exchange is passive and is driven by the prevailing electrochemical gradients
2. During the process of excitation-contraction coupling:
a. Release of Ca2+ causes the binding sites on the thin filaments to be uncovered
b. Acetylcholine binds to muscarinic receptors
c. The transverse tubules release Ca2+ in response to depolarization of the cell through an unknown mechanism
d. Cross-bridges form when ATP binds to myosin
Correct answer: (a.) Release of Ca2+ causes the binding sites on the thin filaments to be uncovered
• Ca2+ binds to troponin, inducing a conformational change that is transmitted to tropomyosin. Tropomyosin shifts and exposes the myosin binding sites, so that cross-bridge cycling can occur
• Acetylcholine binds to nicotinic receptors at the motor end plate
• Located in the T-tubule membrane, closely associated with the foot of the SR Ca2+ channel, is the T-tubule voltage sensor. The voltage sensor changes conformation in response to the depolarization of the action potential. This conformational change is transmitted to the foot of the SR Ca2+ channel, causing it to open and allowing Ca2+ Note that this direct mechanical interaction between the T-tubule voltage sensor and the SR Ca2+ channel is specific for excitation-contraction coupling in skeletal muscle. There are different mechanisms and different sources of Ca2+ used in smooth muscle excitation-contraction coupling. Thus, the mechanism of Ca2+ release is known.
• Cross-bridges form between the actin filaments and the myosin head
A. Have membranes similar to the cell membrane.
B. Are the chief site for protein synthesis.
C. Are the chief sites for generation of ATP.
D. Are more numerous in brown than in white fat cells.
E. Are absent near the membranes of actively secreting cells.
A. True – Both membranes have the same lipid bilayer structure.
B. False – This applies to the ribosomes.
C. True – ATP is formed by oxidative phosphorylation.
D. True – Brown fat cells can generate energy, and hence heat, more rapidly.
E. False – They are concentrated where most energy is required.
4. The elastic recoil of muscles and tendons in the legs
A. Increases jumping height when someone jumps from a height immediately before take off.
B. Improves performance during sprinting.
C. Contributes more to performance when sprinting on a cinder track than on a concrete surface.
D. Can be improved by training.
E. Is greater in weight lifters than in skiers.
A. True – The elastic tissue in extensor muscles is stretched by the initial downward jump.
B. True – Elastic recoil aids the activity independently of muscular contractions.
C. False – The concrete surface ‘reflects’ more of the energy stored during landing the foot on the surface.
D. True – Training which stretches the muscles achieves this.
E. False – Compared with skiers, weight lifters produce little muscle stretch and rebound during training.
5. Normal blood clotting requires
A. Inactivation of heparin.
B. Inactivation of plasmin (fibrinolysin).
C. Calcium ions.
D. An adequate intake of vitamin K.
E. An adequate intake of vitamin C.
A. False – The anticoagulant effects of heparin are overwhelmed.
B. False – Blood clots in spite of the fibrinolytic system.
C. True – Removal of calcium ions prevents clotting.
D. True – Vitamin K is needed by the liver for synthesis of prothrombin and other factor
E. False – The spontaneous bleeding from the gums etc. seen in scurvy is due to capillary abnormality, not a clotting defect.