Free Circulation MCQs with Answers
695 Circulation MCQs from Biology, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
The circulatory system covers the chambers, valves and conducting pathway of the human heart, along with the cardiac cycle and control of heartbeat. It compares arteries, veins and capillaries by structure and function, and explains how the lymphatic system returns tissue fluid, transports absorbed fats and supports immunity.
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Read the Circulation notesFree MDCAT chapter notes with key terms695 questions · page 21 of 35
- A. Small fat globules
- B. Large polypeptides
- C. Large fat globules
- D. Small polypeptides
Explanation: The lacteals of villi absorb large fat globules, which are released by interstitial cells after the products of digestion of fats are…
Correct answer: Large fat globules402. The heart contracts:
- A. Voluntarily
- B. Passively
- C. Irregularly
- D. Rhythmically
Explanation: Cardiac contraction is set at a rhythmic cycle. This is correct as the heart contracts and relaxes periodically in a specific rhythm, this…
Correct answer: Rhythmically- A. Right side
- B. Left side
- C. Lower chambers
- D. Upper chambers
Explanation: The right chambers of heart right i.e. atrium and right ventricle contain deoxygenated blood.
Correct answer: Right side- A. Papillary muscles
- B. Papillary muscles and wall of tricuspid valve
- C. Flaps of tricuspid valve
- D. Walls of the right ventricle
Explanation: The flaps of bicuspid and tricuspid valves are similarly attached through chordae tendinae to papillary muscles of the walls of ventricles.
Correct answer: Papillary muscles and wall of tricuspid valve- A. Right atrium
- B. Pulmonary trunk
- C. Left ventricle
- D. Left atrium
Explanation: When the right ventricle contracts, the blood is passed to the pulmonary trunk.
Correct answer: Pulmonary trunk- A. Tricuspid valve
- B. Bicuspid valve
- C. Semilunar valve
- D. Sphincter valve
Explanation: The left atrium passes the blood via the bicuspid valve, also known as the mitral valve, to the left ventricle.
Correct answer: Bicuspid valve- A. Bicuspid
- B. Tricuspid
- C. Sphincter
- D. Semilunar
Explanation: At the base of the aorta, there are two semilunar valves, known as the aortic valve.
Correct answer: Semilunar- A. Hepatic portal vein
- B. Iliac vein
- C. Hepatic vein
- D. Renal vein
Explanation: Hepatic portal vein collects blood from the entire ailmentary canal and carries it to the inferior vena cava.
Correct answer: Hepatic portal vein- A. Systole
- B. Diastole
- C. Atrial systole
- D. Ventricular systole
Explanation: Diastole is the phase of relaxation in the cardiac cycle. During diastole, the heart chambers relax and fill with blood.
Correct answer: Diastole- A. Plasma
- B. Blood proteins
- C. Blood cells
- D. Both B and C
Explanation: Plasma constitutes 55% of total blood volume. Composed of 90% water, salts, lipids and hormones, it is especially rich in proteins…
Correct answer: Plasma- A. 10 ml
- B. 20 ml
- C. 30 ml
- D. 45 ml
Explanation: When oxygen tension is 115 mm mercury, haemoglobin is 98% saturated and therefore contains 19.6 (≈ 20) ml of oxygen per 100 ml of blood.
Correct answer: 20 ml- A. Diffusion
- B. Transpiration
- C. Osmosis
- D. Root pressure
Explanation: Various ions from the soil are actively transported into the vascular tissues of roots, water follows its potential gradient and increase…
Correct answer: Root pressure- A. Influx of potassium ions
- B. Efflux of potassium ions
- C. Influx of hydrogen ions
- D. Influx of calcium ions.
Explanation: The mechanism of opening and closing of stomata is explained by active K + ion transport theory. So option A is correct.
Correct answer: Influx of potassium ions- A. Erythrocytes
- B. Leucocytes
- C. Neutrophils
- D. Thrombocytes
Explanation: Thrombocytes are called blood platelets.They are minute discshaped cell fragments in mammalian blood.
Correct answer: Thrombocytes- A. Lymph = Plasma + RBC + WBC
- B. Blood = Plasma + RBC + WBC + Platelets
- C. Plasma = Blood - Lymphocytes
- D. Serum = Blood + Fibrinogen
Explanation: Blood is a fluid connective tissue that circulates through our body and performs various functions, including transport of oxygen…
Correct answer: Blood = Plasma + RBC + WBC + Platelets- A. Gall bladder
- B. Kidney
- C. Spleen
- D. Liver
Explanation: (c) : Spleen is a vertebrate organ, lying behind the stomach, that is basically a collection of lymphoid tissue.
Correct answer: Spleen- A. Brain
- B. Heart
- C. Kidney
- D. Pancreas
Explanation: (b) : 'Bundle of His' is a part of heart. A bundle of nodal fibres, atrioventricular bundle (AV bundle), continues from the…
Correct answer: Heart- A. supply oxygenated blood to the different organs
- B. carry blood away from the heart to different organs
- C. break up into capillaries which reunite to form a vein
- D. carry blood from one visceral organ to another visceral organ.
Explanation: (b) : Arteries and veins are main blood vessels. Arteries carry blood from the heart to different body parts.
Correct answer: carry blood away from the heart to different organs- A. muscles
- B. arteries
- C. veins
- D. lymph vessels
Explanation: (c) : Intravenous injection is given for rapid distribution of drugs/substances.
Correct answer: veins- A. eosinophils and lymphocytes
- B. neutrophils and monocytes
- C. neutrophils and eosinophils
- D. lymphocytes and macrophages
Explanation: (b) : Phagocytes are cells that are able to engulf and breakdown foreign particles, cell debris and disease-producing microorganisms.
Correct answer: neutrophils and monocytes