Body fluids and circulation practice · Mixed difficulty

Option C (Left ventricle, aorta and inferior vena cava) is correct because the systemic circulation involves the left ventricle pumping blood into the aorta, which then circulates to the body and returns to the heart via the inferior vena cava.

Option B (Tricuspid and bicuspid valves) is correct because the increase in intraventricular pressure during ventricular systole causes the atrioventricular valves (tricuspid and bicuspid) to close, preventing backflow of blood into the atria.

Option C (100 beats per minute) is correct because stroke volume is the difference between end-diastolic and end-systolic volumes (100 mL - 50 mL = 50 mL). Cardiac output is stroke volume multiplied by heart rate, so heart rate = cardiac output / stroke volume = 5000 mL / 50 mL = 100 beats per minute.

Option A (Circulatory system) is correct because viper venom primarily affects the circulatory system, causing issues like blood clotting and hemorrhaging.

Option B is correct because the liver detoxifies ammonia and converts it into urea, which is then transported in the blood to the kidneys for excretion.

Option D ($A, B, AB$) is correct because these are the only possible blood groups resulting from the given parental genotypes.

Option B (Coronary artery disease) is correct because atherosclerosis is a primary cause of coronary artery disease.

Option D (The flow of blood would decrease in pulmonary artery) is incorrect. Option C (The flow of blood would decrease in aorta) is correct because the mitral valve prevents backflow from the left ventricle to the left atrium. If the chordae tendineae are cut, the mitral valve will not close properly, causing backflow and reducing the amount of blood ejected into the aorta.

Option B (Maximum filling of ventricles takes place) is correct because during joint diastole, both atria and ventricles are relaxed, allowing for maximum ventricular filling.

Option C (Coronary arteries) is correct because coronary arteries are the blood vessels that supply oxygenated blood to the heart muscle itself.

Option B (Prevent clotting) is correct because calcium ions are essential for several steps in the blood clotting cascade.

Option C (4-10 min) is correct because the normal blood clotting time in humans typically ranges from 4 to 10 minutes.

Option A (I-gene) is correct because the ABO blood groups are determined by the I gene, which has three alleles: $I^A$, $I^B$, and i.

Option C (ventricular systole) is correct because blood pressure is at its maximum during the contraction of the ventricles.

Option B (Periplaneta) is correct because Periplaneta (cockroach) is an arthropod and possesses an open circulatory system.

Option C (120-80 = 40 mm Hg) is correct because pulse pressure is calculated by subtracting diastolic pressure from systolic pressure.

Option C (Arthropods and Mollusca) is correct because arthropods and most molluscs (except cephalopods) have open circulatory systems.

Option D (AB) is correct because if the father is A and the son is O, the mother must have at least one 'i' allele, which is not possible if the mother is AB.

Option A (Capillaries surrounding the tissue cells) is correct because oxygen is released from the blood into the tissues at the capillaries surrounding the tissue cells due to the concentration gradient.

Option B (In the wall of right atrium) is correct because the sinoatrial (SA) node, which acts as the heart's natural pacemaker, is located in the wall of the right atrium.

Option A (Enteric heart in lower vertebrates) is correct because systemic heart refers to the enteric heart in lower vertebrates.

Option D (Oxygenated blood is pumped into the aorta and deoxygenated blood is pumped into the pulmonary artery) is correct because during ventricular systole, the left ventricle pumps oxygenated blood into the aorta, and the right ventricle pumps deoxygenated blood into the pulmonary artery.

Option A (After the auricular/atrial systole) is correct because ventricular systole occurs after the atria have contracted to fill the ventricles.

Option A (Arteries) is correct because pulse beat is measured from arteries, as they carry blood under high pressure from the heart, allowing for a palpable pulsation.

Option A (Heart failure) is correct because heart failure is defined as the heart's inability to pump blood effectively enough to meet the body's needs.

Option D (Red bone marrow) is correct because in adult mammals, erythrocytes (red blood cells) are formed in the red bone marrow.

Option A (70 – 75 min$^ - 1$) is correct because the sinoatrial node (SAN) typically generates impulses at a rate of 70-75 per minute.

Option B (If both A and R are true, but R is not the correct explanation of A) is correct because both Thrombin being essential for blood clotting and Calcium ions playing an important role in blood clotting are true statements, but calcium's role is not the primary reason why thrombin is essential.

Option B (Medulla oblongata) is correct because the cardiac center, which regulates heart rate and contractility, is located in the medulla oblongata.

Option B (Blood has RBCs and WBCs, while lymph has only WBCs) is correct because lymph is essentially filtered blood plasma with white blood cells, but lacking red blood cells.