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 18 of 35
- A. 10
- B. 20
- C. 40
- D. 200
Explanation: Under typical conditions, the solubility of oxygen in water is approximately 8 milligrams per liter (mg/L) or 8 parts per million (ppm).
Correct answer: 10- A. Carboxyhemoglobin
- B. Plasma proteins
- C. Bicarbonate ions
- D. Histamines
Explanation: When carbon dioxide (CO2) combines with the amino group of hemoglobin, the product formed is "Carboxyhemoglobin." Carboxyhemoglobin is a…
Correct answer: Carboxyhemoglobin- A. Perimysium
- B. Peritoneum
- C. Pleural membrane
- D. Pericardium
Explanation: The pericardium is a thin sac that surrounds the heart. It protects and lubricates the heart to reduce friction when it pumps.
Correct answer: Pericardium- A. Cell-Mediated
- B. Hormonal
- C. Humoral
- D. Phototactic
Explanation: This option is the correct response in the given context. Humoral response refers to the immune response involving the production of…
Correct answer: Humoral- A. Tricuspid Valve
- B. Bicuspid valve
- C. Semilunar valve
- D. Septum
Explanation: The valve lying between the right atrium and the right ventricle is known as the tricuspid valve due to it having three flaps.
Correct answer: Tricuspid Valve- A. Smooth Muscles
- B. Papillary Muscles
- C. Intercostal Muscles
- D. Skeletal Muscles
Explanation: Papillary Muscles: This option is the correct answer. The flaps of the tricuspid valves are attached to muscular extensions of the right…
Correct answer: Papillary Muscles- A. As carboxylase myoglobin
- B. Freely as CO2
- C. With proteins in plasma
- D. As bicarbonate
Explanation: About 70% of CO2 is transported as bicarbonate ions.
Correct answer: As bicarbonate348. Granulocytes are:
- A. Monocytes, Eosinophils, Basophils
- B. Basophils, Macrophages, Neutrophils
- C. Neutrophils, Eosinophils, Basophils
- D. Monocytes, Macrophages, Basophils
Explanation: Neutrophils, Eosinophils, Basophils: This option is the correct answer.
Correct answer: Neutrophils, Eosinophils, Basophils- A. Homeostatic Response
- B. Primary response
- C. Behavioral response
- D. Cell-mediated response
Explanation: Transplant rejection is caused primarly by a cell -mediated immune response to HLA antigens expressed on donor antigen-presenting cells…
Correct answer: Cell-mediated response- A. MHC complex
- B. Immunogen
- C. Mucus
- D. Antibodies
Explanation: d) Antibodies: Antibodies, also known as immunoglobulins, are proteins produced by the immune system in response to the presence of…
Correct answer: Antibodies- A. B lymphocytes
- B. A lymphocytes
- C. T lymphocytes
- D. B and T lymphocytes
Explanation: B lymphocytes are a type of white blood cells which produce antibodies, which protect the body against antigens.
Correct answer: B lymphocytes- A. Liver
- B. Bursa of fabricius
- C. Thymus gland
- D. Spleen
Explanation: T-lymphocytes are a type of immune cells. They originate from stem cells in the bone marrow and are sent to the thymus gland for…
Correct answer: Thymus gland- A. Physical barrier
- B. Mechanical barriers
- C. Chemical barriers
- D. Biological barriers
Explanation: First defense line is physical as well as chemical barrier but skin and mucous are physical barrier as they are not involve in chemical…
Correct answer: Physical barrier- A. Active
- B. Passive
- C. Humoral
- D. Specific
Explanation: Passive immunity provides immediate protection by injecting immunoglobulins, and this protection lasts for a short period of time, which…
Correct answer: Passive- A. Nucleus
- B. Red color
- C. Fluids
- D. Haemoglobin
Explanation: Mature mammalian red blood cells, also known as erythrocytes, lack a nucleus.
Correct answer: Nucleus- A. 50%
- B. 60%
- C. 45%
- D. 55%
Explanation: Blood plasma constitutes about 55% of blood volume, and contains water, salts, and proteins.
Correct answer: 55%- A. Platelets
- B. B-Lymphocytes
- C. Eosinophils
- D. T-Lymphocytes
Explanation: The thymus gland is involved in the maturation of T cells, a type of white blood cell that plays a vital role in the immune system.
Correct answer: T-Lymphocytes- A. Antigens
- B. Immunogens
- C. Serum
- D. Immunoglobulins
Explanation: Immunoglobulins provide passive immunity as the body does not have to produce antibodies, instead the injected antibodies offer a few…
Correct answer: Immunoglobulins- A. Physical Barriers
- B. Mechanical Barriers
- C. Chemical Barriers
- D. Biological Barriers
Explanation: Mucous membranes are a type of epithelial tissue that lines the inside of many organs, including the respiratory tract, digestive tract…
Correct answer: Physical Barriers- A. Passive Immunity
- B. Active Immunity
- C. Vaccination
- D. Natural Activity Immunity
Explanation: Passive immunity can be obtained immediately by injecting antitoxins, like in the case of tetanus.
Correct answer: Passive Immunity