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: Atrial natriuretic peptide causes
A) Sodium reabsorption
B) Sodium excretion
C) Vasoconstriction
D) Increased ADH secretion
✅ Correct Answer: B
Explanation: ANP promotes natriuresis to reduce blood volume and pressure.
Q: Primary muscle used during normal quiet breathing
A) Internal intercostals
B) Sternocleidomastoid
C) External intercostals
D) Diaphragm
✅ Correct Answer: D
Explanation: The diaphragm contracts and flattens during inspiration at rest.
Q: The region of the brain that controls body temperature
A) Pons
B) Medulla
C) Cerebellum
D) Hypothalamus
✅ Correct Answer: D
Explanation: The hypothalamus regulates body temperature via autonomic responses.
Q: A decrease in blood pH will cause hemoglobin to
A) Increase oxygen binding
B) Form carboxyhemoglobin
C) Release more oxygen
D) Denature
✅ Correct Answer: C
Explanation: Lower pH (Bohr effect) shifts the curve right, enhancing oxygen delivery.
Q: The fastest phase of depolarization in cardiac muscle
A) Phase 4
B) Phase 2
C) Phase 0
D) Phase 1
✅ Correct Answer: C
Explanation: Phase 0 represents rapid Na⁺ influx, causing steep depolarization.
Q: The ion mainly responsible for repolarization in neurons
A) Sodium
B) Potassium
C) Calcium
D) Chloride
✅ Correct Answer: B
Explanation: Outward movement of K⁺ restores resting membrane potential after depolarization.
Q: Gastric acid secretion is stimulated by
A) Glucagon
B) Secretin
C) Gastrin
D) Cholecystokinin
✅ Correct Answer: C
Explanation: Gastrin stimulates parietal cells to release HCl in the stomach.
Q: The function of bile salts
A) Enzyme activation
B) Emulsification of fats
C) Protein denaturation
D) Carbohydrate digestion
✅ Correct Answer: B
Explanation: Bile salts break down large fat droplets into smaller micelles for digestion.
Q: The phase of the cardiac cycle when ventricles contract
A) Atrial systole
B) Ventricular systole
C) Diastasis
D) Isovolumetric relaxation
✅ Correct Answer: B
Explanation: During ventricular systole, the ventricles contract and eject blood.
Q: The oxygen-hemoglobin dissociation curve shifts right due to
A) Increased 2,3-BPG
B) Decreased temperature
C) Alkalosis
D) Low CO₂
✅ Correct Answer: A
Explanation: 2,3-BPG decreases hemoglobin’s affinity for oxygen, enhancing release.