Body fluids and circulation practice · Mixed difficulty

Option B (Ventricles) is correct because papillary muscles are located in the ventricles of the heart and attach to the atrioventricular valves via chordae tendineae.

Option B (Mother $R{h^{ - Ve}}$ and foetus $R{h^{ + Ve}}$) is correct because erythroblastosis foetalis occurs when an Rh-negative mother carries an Rh-positive fetus, leading to the mother's immune system attacking the fetal red blood cells.

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 D (Peak P – Initiation of left atrial contraction only) is incorrect. Peak P represents the initiation of contraction of both atria, not just the left atria. Option A (Complex QRS – One complete Pulse) is incorrect because QRS represents ventricular depolarization, not a complete pulse. Option B (Peak T – Initiation of total cardiac contraction) is incorrect because T represents ventricular repolarization. Option C (Peak P and Peak R together – Systolic and diastolic blood pressure) is correct because the ECG indirectly reflects blood pressure changes during systole and diastole.

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 A (If both the assertion and the reason are true and the reason is a correct explanation of the assertion) is correct because closed circulatory systems allow for precise regulation of fluid flow, making them more advantageous than open systems.

Option B (Neutrophils) is correct because neutrophils are characterized by having a multi-lobed nucleus, typically with 3-5 lobes, but can sometimes have 5-7 lobes.

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 (III, IV, I and II) is correct because the correct sequence of events in blood clotting is: 1. Thromboplastin formation, 2. Conversion of prothrombin to thrombin, 3. Conversion of fibrinogen to fibrin, and 4. Formation of clot.

Option A (Coronary sinus) is correct because the coronary sinus is a large vein on the posterior surface of the heart that collects deoxygenated blood from the heart wall and drains it into the right atrium.

Option D (Truncus arteriosus) is correct because the spiral valve is present in the truncus arteriosus of amphibians and some fish, helping to separate oxygenated and deoxygenated blood.

Option A is correct because leucocytes (WBCs) are nucleated, present in a concentration of 6000-8000 mm^(-3) of blood, and are short-lived.

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 C (Early joint diastole) is correct because the \"dub\" heart sound is produced by the closing of the semilunar valves at the beginning of ventricular diastole (early joint diastole).

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 A (Increase in number) is correct because at high altitudes, the body compensates for the lower oxygen availability by producing more red blood cells (RBCs) to increase the oxygen-carrying capacity of the blood.

Option A (RBC) is correct because Rouleaux formation is the stacking of red blood cells (RBCs) which look like stacks of coins.

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

Option C (Rh and ABO blood group) is correct because the ABO and Rh blood group systems are the two most clinically significant blood group systems in humans.

Option B (B) is correct because if the man were homozygous (AA), he could only pass on A alleles. The presence of B blood group offspring indicates he must be heterozygous (AO) to contribute an O allele.

Option C (Extra cellular fluid) is correct because most of our cells are surrounded by extracellular fluid, which provides nutrients and removes waste.

Option C (A is true but R is false) is correct because a balloon pump is used to assist the heart, but not when the heart is removed from the body.

Option A (Carry blood away from the heart to different organs) is correct because arteries are defined as blood vessels that carry blood away from the heart.

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.