All Free Physiology MCQs with Answers

• A. Heart rate
• B. Peripheral resistance
• C. Systolic blood pressure
• D. Venous return

Explanation: Cardiac output is calculated as heart rate multiplied by stroke volume, and venous return strongly influences stroke volume.

• A. 30 ml
• B. 130 ml
• C. 70 ml
• D. 5 liters

Explanation: Normal stroke volume is approximately 70 mL per ventricle per beat, calculated as end-diastolic volume minus end-systolic volume.

• A. The bundle of His
• B. The sinoatrial node
• C. All cardiac muscle
• D. The cervical ganglion

Explanation: The sinoatrial node is the normal pacemaker because it has the highest intrinsic rate of spontaneous depolarisation.

• A. Closure of the aortic and pulmonary valves
• B. Opening of the aortic and pulmonary valves
• C. Closure of the mitral and tricuspid valves
• D. Opening of the mitral and tricuspid valves

Explanation: The first heart sound (S1) occurs at the beginning of ventricular systole when the atrioventricular valves, mitral and tricuspid, close.

• A. Circannual
• B. Circa triginatan
• C. Circa sestin
• D. Circadian

Explanation: A circadian rhythm repeats approximately every 24 hours, matching daily biological changes such as the sleep-wake cycle.

• A. Acetylcholine
• B. Heparin
• C. Bradykinin
• D. Insulin

Explanation: Insulin is an endocrine hormone released into the blood and acting at distant sites.

• A. Propagation
• B. Depolarization
• C. All or none law
• D. Hyper polarization

Explanation: The end-plate potential is a local, graded depolarization produced when acetylcholine opens nicotinic channels at the neuromuscular…

• A. Interstitium
• B. Plasma
• C. Cell
• D. Bone

Explanation: Potassium is the major intracellular cation, maintained at a much higher concentration inside cells than in plasma or interstitial fluid.

• A. Na effux
• B. Na influx
• C. K influx
• D. K efflux

Explanation: Repolarization is mainly caused by opening of voltage-gated potassium channels, allowing K⁺ to flow out of the cell.

• A. Centrally placed nuclei
• B. Transverse striation
• C. Cylindrical
• D. Multiple nuclei

Explanation: Skeletal muscle fibres are cylindrical, striated and multinucleated, with nuclei located peripherally rather than centrally.

• A. Failure of acetylcholine to diffuse
• B. Failure of break down of calcium bridges
• C. Failure of ATP supply
• D. None of the above

Explanation: After death, ATP production stops, so myosin heads cannot detach from actin and the muscles become rigid.

• A. Is not essential for contraction to occur
• B. Has a prolonged plateau phase?
• C. Begins with an, in ward movement of K+ ins
• D. Spreads in ward to all parts of the muscle via the t- tubule system

Explanation: The skeletal-muscle action potential travels along the sarcolemma and deep into the fibre through the transverse tubules, allowing nearly…

• A. To study muscle activity
• B. Determine class II malocclusion
• C. Determine the centric relation
• D. Determine the centric occlusion

Explanation: Electromyography records the electrical activity of skeletal muscle through surface or needle electrodes, helping assess muscle and…

• A. Contracts when calcium is taken up by sarcoplasmic reticulum
• B. Contraction is initiated by calcium binding to troponin
• C. Contracts when actin and myosin filaments shorten
• D. Contraction is initiated by calcium binding to tropomyosin

Explanation: Calcium released from the sarcoplasmic reticulum binds to troponin C, moving tropomyosin away from actin's binding sites and initiating…

• A. Sarcolemma
• B. Sarcoplasm
• C. Myofibril
• D. Endomysium

Explanation: Myofibrils are the contractile structures within a skeletal-muscle fibre and contain repeating sarcomeres made of actin and myosin.

• A. Protein- C
• B. Myosin
• C. Actin
• D. Troponin

Explanation: Troponin is a regulatory protein that controls actin-myosin interaction in striated muscle in response to calcium.

• A. Skeletal and cardiac
• B. Smooth and cardiac
• C. Smooth and skeletal
• D. All of the above

Explanation: The three main muscle-cell types are skeletal, cardiac, and smooth muscle.

• A. white and brown
• B. White and red
• C. White and gray
• D. White and yellow

Explanation: Skeletal muscle fibres are commonly classified as red fibres, which are oxidative and fatigue-resistant, and white fibres, which are more…

• A. Tomes fibers
• B. Interstitial fibers
• C. Haversian fibers
• D. Sharpey's fibers

Explanation: Sharpey’s fibers are collagen fibers that penetrate and anchor tendons and ligaments to bone.

• A. The muscle moves a load through a distance
• B. The muscle is not able to move the load
• C. The latent period of contraction is shorter than isometric contraction
• D. The length of muscle is increased

Explanation: During isotonic contraction, muscle tension is sufficient to move a load while the muscle length changes, so the load moves through a…