Free Blood Vessels MCQs with Answers

• A. Superior vena cava
• B. Hepatic vein
• C. Pulmonary vein
• D. Renal vein

Explanation: The pulmonary vein returns freshly oxygenated blood from the lungs to the left atrium, so it is the exception to the rule that veins carry…

• A. veins carry deoxygenated blood
• B. blood in veins is at low pressure and would otherwise flow backwards
• C. arteries have thinner walls
• D. veins lie closer to the skin

Explanation: By the time blood reaches the veins the pressure created by the heart has largely been lost in the capillaries, so flow depends on the…

• A. one cell thick, formed of a single layer of endothelium
• B. made of smooth muscle that contracts rhythmically
• C. lined with valves at close intervals
• D. thick and elastic to withstand pressure

Explanation: A capillary wall is a single layer of flattened endothelial cells, giving a diffusion distance of well under a micrometre, and the…

• A. capillaries
• B. venules
• C. aorta
• D. venae cavae

Explanation: Pressure is greatest as blood leaves the left ventricle into the aorta and falls steadily along the circuit, with the sharpest drop across…

• A. 80/120 mm Hg
• B. 120/80 mm Hg
• C. 200/100 mm Hg
• D. 60/40 mm Hg

Explanation: The larger figure is the systolic pressure during ventricular contraction and the smaller is the diastolic pressure while the ventricles…

• A. carries oxygenated blood to the liver
• B. carries blood directly from the heart to the liver
• C. has thicker walls than any artery
• D. begins in the capillaries of the gut and ends in the capillaries of the liver

Explanation: A portal vessel runs between two capillary beds instead of returning blood to the heart, so absorbed glucose and amino acids reach the…

• A. Lungs
• B. Body
• C. Right atrium
• D. Pulmonary artery

Explanation: The left ventricle pumps oxygenated blood through the aorta to the entire body (systemic circulation).

• A. AV bundle
• B. Pacemaker of the heart
• C. Valve of the heart
• D. Coronary artery

Explanation: The sinoatrial (SA) node in the right atrium is the natural pacemaker, initiating each heartbeat.

• A. Vena cava
• B. Pulmonary vein
• C. Aorta
• D. Capillary

Explanation: The aorta has the thickest wall to withstand the high pressure of blood ejected from the left ventricle.

• A. Active transport
• B. Ultrafiltration from capillaries
• C. Secretion by cells
• D. Osmosis only

Explanation: Tissue fluid forms by ultrafiltration from arterial ends of capillaries due to hydrostatic pressure.

• A. Arteries: Due to thick walls
• B. Capillaries: due to highest overall cross-sectional area
• C. Veins: due to blood flow against the gravity
• D. Capillaries: Due to two-way blood flow in capillaries

Explanation: Although each capillary is tiny, there are so many in parallel that their combined cross sectional area is far greater than that of the…

• A. Arteries
• B. Capillaries
• C. Veins
• D. none of these

Explanation: Veins return blood towards the heart, using valves and surrounding muscle contractions to prevent backflow, although pulmonary veins are…

• A. Capillaries
• B. Lumen
• C. Platelates
• D. Plasma

Explanation: The lumen is the hollow internal space of a blood vessel through which blood flows.

• A. hypochromia
• B. Anisocytosis
• C. Poikilocytosis
• D. Polychromatophilia

Explanation: Anisocytosis means variation in the size of red blood cells, whereas poikilocytosis means variation in their shape.

• A. Arteries
• B. Veins
• C. Capillaries
• D. None of these

Explanation: Veins generally carry blood toward the heart and commonly transport deoxygenated blood from body tissues.

• A. Neck
• B. Wrist
• C. Elbow
• D. Brain

Explanation: The carotid arteries run through the neck and supply oxygenated blood to the head and brain.

• A. Decrease
• B. Increase
• C. Remain Same
• D. Becomes zero

Explanation: For a given blood flow, reducing vessel radius greatly increases resistance because resistance varies inversely with the fourth power of…

• A. Hepatic artery
• B. Pulmonary artery
• C. Pulmonary vein
• D. Renal artery

Explanation: The pulmonary veins carry oxygenated blood from the lungs to the left atrium of the heart.

• A. Lacking globulins
• B. Lacking albumins
• C. Lacking clotting factors
• D. Lacking antibodies

Explanation: Serum is the liquid left after blood has clotted, so it lacks fibrinogen and other clotting components that were used or removed during…

• A. Platelets in plasma
• B. Proteins in blood
• C. RBC and WBC in blood
• D. Sodium in serum

Explanation: Plasma proteins, especially fibrinogen and globulins, increase the internal friction of blood and therefore contribute substantially to…