Physiology MCQs
Physiology MCQs help medical and dental students develop a thorough understanding of the body's functional mechanisms. These multiple-choice questions focus on various systems such as cardiovascular, respiratory, renal, digestive, endocrine, and neurophysiology. Practicing these MCQs enhances knowledge retention and exam performance in tests like MDCAT, NTS, USMLE, and FCPS. Whether you're preparing for academic exams or professional licensure, these quizzes provide a solid framework for mastering the dynamic processes of the human body.
Q: The oxygen-carrying protein in red blood cells
A) Hemoglobin
B) Myosin
C) Albumin
D) Fibrinogen
✅ Correct Answer: A
Explanation: Hemoglobin binds oxygen in the lungs and releases it in tissues.
Q: The function of surfactant in the lungs
A) Stimulate ciliary motion
B) Reduce surface tension
C) Promote mucus secretion
D) Increase airway resistance
✅ Correct Answer: B
Explanation: Surfactant prevents alveolar collapse by lowering surface tension.
Q: Blood pressure is primarily regulated by
A) Spleen
B) Pulmonary arteries
C) Autonomic nervous system
D) Thymus
✅ Correct Answer: C
Explanation: The autonomic system adjusts heart rate and vessel tone to maintain blood pressure.
Q: Vitamin K is essential for
A) Nerve conduction
B) Red blood cell synthesis
C) Coagulation
D) Bone resorption
✅ Correct Answer: C
Explanation: Vitamin K is required for synthesis of clotting factors in the liver.
Q: Increased secretion of ADH leads to
A) Water retention
B) Diuresis
C) Decreased blood volume
D) Sodium excretion
✅ Correct Answer: A
Explanation: ADH promotes water reabsorption in kidneys, reducing urine output.
Q: Conduction velocity is fastest in
A) Thin myelinated fibers
B) Unmyelinated fibers
C) Large myelinated fibers
D) C fibers
✅ Correct Answer: C
Explanation: Large myelinated fibers conduct impulses more rapidly due to saltatory conduction.
Q: The primary buffer system in the extracellular fluid
A) Bicarbonate buffer
B) Phosphate buffer
C) Protein buffer
D) Hemoglobin buffer
✅ Correct Answer: A
Explanation: The bicarbonate buffer system maintains pH in blood and extracellular fluids.
Q: Increased carbon dioxide levels in blood stimulate
A) Decreased ventilation
B) Metabolic alkalosis
C) Increased ventilation
D) Vasoconstriction
✅ Correct Answer: C
Explanation: Elevated CO₂ levels trigger medullary centers to increase respiratory rate.
Q: The hormone that increases renal water reabsorption
A) Oxytocin
B) Cortisol
C) Antidiuretic hormone
D) Epinephrine
✅ Correct Answer: C
Explanation: ADH increases water permeability in the kidney collecting ducts.
Q: The stimulus for erythropoietin release
A) Acidosis
B) Hyperglycemia
C) Hypoxia
D) Dehydration
✅ Correct Answer: C
Explanation: Erythropoietin is secreted in response to low oxygen to stimulate red blood cell production.