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 basic contractile unit in skeletal muscle is the
A) Fascicle
B) Sarcomere
C) Neuron
D) Myofibril
✅ Correct Answer: B
Explanation: Sarcomeres are repeating units of actin and myosin that contract.
Q: Increased secretion of antidiuretic hormone leads to
A) Blood sugar drop
B) Sodium excretion
C) Water retention
D) Urine dilution
✅ Correct Answer: C
Explanation: ADH promotes water reabsorption in kidneys to conserve fluid.
Q: The resting membrane potential of a neuron is maintained by
A) Glycogen storage
B) Calcium influx
C) Sodium-potassium pump
D) ATP synthase
✅ Correct Answer: C
Explanation: The pump maintains ionic gradients critical for nerve excitability.
Q: Action potential transmission along myelinated fibers is called
A) Saltatory conduction
B) Linear propagation
C) Retrograde flow
D) Continuous depolarization
✅ Correct Answer: A
Explanation: Impulses jump between nodes of Ranvier in myelinated neurons.
Q: The primary function of erythropoietin is to stimulate
A) Blood clotting
B) White blood cell migration
C) Platelet formation
D) Red blood cell production
✅ Correct Answer: D
Explanation: Erythropoietin signals bone marrow to increase RBC synthesis.
Q: Gastrin secretion is triggered by
A) Lung expansion
B) Blood glucose
C) Protein in stomach
D) Skin temperature
✅ Correct Answer: C
Explanation: Gastrin is released in response to protein to promote acid secretion.
Q: The main pacemaker potential in cardiac muscle originates due to
A) Cl⁻ outflow
B) Ca²⁺ efflux
C) Fast K⁺ influx
D) Slow Na⁺ influx
✅ Correct Answer: D
Explanation: Pacemaker cells slowly depolarize due to inward Na⁺ current.
Q: Filtration at the glomerulus is driven primarily by
A) Osmotic gradient
B) Hydrostatic pressure
C) ATP energy
D) Active transport
✅ Correct Answer: B
Explanation: Blood pressure forces plasma through the glomerular membrane.
Q: During depolarization, sodium channels become
A) Inactive
B) Open
C) Unchanged
D) Blocked
✅ Correct Answer: B
Explanation: Voltage-gated Na⁺ channels open rapidly, allowing inward current.
Q: Oxygen-hemoglobin binding is enhanced by
A) Acidosis
B) High pH
C) Low temperature
D) High CO₂
✅ Correct Answer: B
Explanation: Alkaline conditions shift the oxygen dissociation curve to the left.