Physiology MCQs
Physiology MCQs help medical and dental students master body functions across cardiovascular, respiratory, renal, digestive, endocrine, and neurophysiology systems. Ideal for MDCAT, NTS, USMLE, and FCPS, these quizzes boost retention and exam success.
Q: The effect of sympathetic stimulation on heart rate is
A) Increase
B) Irregularity
C) Decrease
D) No change
✅ Correct Answer: A
Explanation: Sympathetic activity releases norepinephrine to speed up the heart rate.
Q: The neurotransmitter used at neuromuscular junctions is
A) GABA
B) Acetylcholine
C) Serotonin
D) Dopamine
✅ Correct Answer: B
Explanation: Acetylcholine is released by motor neurons to initiate muscle contraction.
Q: The hormone secreted in response to high blood glucose is
A) Insulin
B) Glucagon
C) Cortisol
D) Aldosterone
✅ Correct Answer: A
Explanation: Insulin lowers blood sugar by promoting glucose uptake and storage.
Q: The main organ responsible for detoxifying blood is the
A) Liver
B) Lung
C) Kidney
D) Spleen
✅ Correct Answer: A
Explanation: The liver metabolizes toxins and drugs through enzymatic pathways.
Q: The largest volume of blood is found in the
A) Heart
B) Arteries
C) Veins
D) Capillaries
✅ Correct Answer: C
Explanation: Veins function as blood reservoirs and contain most of the circulating blood.
Q: The role of platelets is to aid in
A) Immune defense
B) Blood clotting
C) Hormone production
D) Oxygen transport
✅ Correct Answer: B
Explanation: Platelets aggregate and release factors essential for clot formation.
Q: The movement of food through the digestive tract is aided by
A) Peristalsis
B) Filtration
C) Retraction
D) Diffusion
✅ Correct Answer: A
Explanation: Peristaltic waves push food along the gastrointestinal tract.
Q: The fluid secreted by serous membranes to reduce friction is called
A) Cerebrospinal fluid
B) Serous fluid
C) Synovial fluid
D) Mucus
✅ Correct Answer: B
Explanation: Serous fluid lubricates organs and reduces mechanical stress.
Q: The gas that binds to hemoglobin more tightly than oxygen is
A) Hydrogen
B) Carbon monoxide
C) Nitrogen
D) Sulfur dioxide
✅ Correct Answer: B
Explanation: Carbon monoxide forms a stable complex with hemoglobin, blocking oxygen transport.
Q: The portion of the brain that regulates hunger and thirst is the
A) Medulla
B) Pons
C) Cerebellum
D) Hypothalamus
✅ Correct Answer: D
Explanation: The hypothalamus contains centers for appetite and fluid balance control.