Body fluids and circulation practice · Easy

Option D (Both (a) and (b)) is correct because the two prominent heart sounds heard through a stethoscope are "Lub" and "Dub".

Option C (When one cell receives a signal to contract, its neighbours cell will also need signal to contract) is correct because cardiac muscle cells are connected by gap junctions within intercalated discs, allowing for rapid spread of electrical signals and coordinated contraction without each cell needing an independent signal.

Option A is correct because blood is composed of plasma, red blood cells (RBCs), white blood cells (WBCs), and blood platelets.

Option B (Interstitial fluid) is correct because interstitial fluid is the fluid that surrounds cells in tissues, formed by filtration of plasma from capillaries.

Option D (thoracic lymphatic duct) is correct because the thoracic duct receives lymph from the legs and most of the body.

Option B (Heparin) is correct because Heparin is a natural anticoagulant that prevents blood clotting within blood vessels.

Option B (B) is correct because agglutination with anti-B serum indicates the presence of B antigens on the red blood cells, defining blood group B.

Option C (I and IV) is correct because arthropods and molluscs (except cephalopods) possess an open circulatory system.

Option A (Heart of mammals) is correct because the myocardium is the muscular tissue of the heart.

Option B (CAD) is correct because atherosclerosis is a primary cause of Coronary Artery Disease (CAD).

Option A (Right atria and right ventricle) is correct because the tricuspid valve is located between the right atrium and the right ventricle.

Option B (Pressure exerted against the wall of brachial artery) is correct because blood pressure is commonly measured at the brachial artery.

Option D (Pulmonary circulation) is correct because the pathway described involves deoxygenated blood going to the lungs and oxygenated blood returning to the heart, which is the definition of pulmonary circulation.

Option C (Semilunar values) is correct because during joint diastole, the atria and ventricles are relaxed, and the semilunar valves (aortic and pulmonary) are closed to prevent backflow of blood into the ventricles.

Option C (blood clotting) is correct because Fibrinogen is a crucial protein in blood plasma that is converted into fibrin during the blood clotting process.

Option B (3600 mL) is correct because cardiac output is calculated by multiplying heart rate by stroke volume: 72 beats/min * 50 mL/beat = 3600 mL/min.

Option D (This condition can be avoided by administering anti-Rh antibodies to the foetus immediately after the delivery of the first child.) is correct because anti-Rh antibodies (RhoGAM) are administered to the *mother* immediately after the delivery of the first Rh+ve child, not to the foetus.

Option C (D antigen on RBC) is correct because O positive blood group means that there is no A or B antigen on RBCs, but the D antigen (Rh factor) is present.

Option B (O and AB blood groups, respectively) is correct because O blood group lacks A and B antigens, making it a universal donor, while AB blood group lacks anti-A and anti-B antibodies, making it a universal recipient.

Option B (Pulmocutaneous vein) is correct because the pulmocutaneous vein carries oxygenated blood from the lungs and skin back to the heart in frogs.

Option A (SA-node) is correct because the sinoatrial (SA) node is the heart's natural pacemaker and initiates the heartbeat impulse.

Option A is correct because a low partial pressure of oxygen ($P{o_2}$) in the arterial blood results in the release of $CO_2$ from the cells into the blood for transport to the lungs.

Option B (foetus) is correct because the heartbeat rate is generally higher in foetuses than in adults or elderly people.

Option C (A-left, B-right, C-deoxygenated) is correct because the left atrium receives oxygenated blood and the right atrium receives deoxygenated blood in amphibians and reptiles.

Option C (Interstitial fluid) is correct because gases, nutrients, and waste products are exchanged between blood and cells via the interstitial fluid.

Option B (Lack of haemoglobin) is correct because leucocytes (white blood cells) lack hemoglobin, which is the pigment that gives red blood cells their color.

Option A (Medulla oblongata) is correct because cardiovascular reflexes, which regulate blood pressure and heart rate, are primarily controlled by the medulla oblongata.

Option B (Rh positive (Rh + ve)) is correct because individuals with the Rh antigen on their red blood cells are classified as Rh positive.

Option B (Bone marrow) is correct because bone marrow is the primary site of hematopoiesis, where blood cells, including primary blood cells, are formed.

Option C (More WBCs and no RBCs) is correct because lymph is a fluid derived from tissue fluid and contains white blood cells but lacks red blood cells.