Circulation: 17 MCQs with answers

RBCs - Oxygen transport, Platelets - Clotting, WBCs - Immunity

RBCs carry oxygen via haemoglobin, platelets help in clotting, and WBCs provide immunity.

Haemoglobin

Haemoglobin is the iron-containing protein in RBCs that binds and transports oxygen.

Lymph

Lymph is the fluid tissue of the lymphatic system, similar to plasma but with less protein and no RBCs.

Sinoatrial node

The sinoatrial (SA) node is the pacemaker of the heart that initiates each heartbeat.

Arteries - Carry blood away from heart, Veins - Carry blood to heart, Capillaries - Exchange of materials

Arteries carry blood away from the heart, veins carry blood to the heart, and capillaries are sites of exchange of materials.

Serum

Serum is the fluid remaining after blood clotting, so it lacks clotting factors.

Anemia

Anemia is a condition characterized by a low RBC count or reduced haemoglobin.

True

The SA node initiates the electrical impulses that set the rhythm of the heart.

False

Lymph is not pumped by the heart; it flows due to skeletal muscle contractions and breathing movements.

It is slightly alkaline and contains plasma and formed elements

Human blood is slightly alkaline (pH ~7.4) and consists of plasma and formed elements (RBCs, WBCs, platelets).

Right atrium - Receives deoxygenated blood, Left ventricle - Pumps blood to body, Right ventricle - Pumps blood to lungs

Right atrium receives deoxygenated blood, left ventricle pumps oxygenated blood to the body, and right ventricle pumps deoxygenated blood to the lungs.

It pumps blood into the pulmonary artery from the left ventricle

The pulmonary artery receives blood from the right ventricle, not the left ventricle. The left ventricle pumps blood into the aorta.

It involves fibrinogen to fibrin conversion and requires calcium ions

Blood clotting involves conversion of fibrinogen to fibrin, requires calcium ions, and is initiated by platelets. It can occur in any blood vessel.

A - Antigen A, B - Antigen B, AB - Both antigens A and B

Blood group A has antigen A, B has antigen B, and AB has both antigens A and B.

It begins with ventricular contraction

The cardiac cycle begins with atrial systole, not ventricular contraction. It lasts about 0.8 seconds and includes systole and diastole.

Tricuspid - Between right atrium and ventricle, Mitral - Between left atrium and ventricle, Aortic - At the base of the aorta

Tricuspid valve is between right atrium and ventricle, mitral (bicuspid) valve between left atrium and ventricle, and aortic valve at the base of the aorta.

It is an antigen on RBCs and Rh-positive individuals lack anti-Rh antibodies

Rh factor is an antigen on RBCs. Rh-positive individuals do not have anti-Rh antibodies. Rh incompatibility can cause erythroblastosis fetalis.