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Q1. The rhythmic contraction and relaxation of the heart is called:
The rhythmic contraction and relaxation of the heart is called a heartbeat. It consists of systole (contraction) and diastole (relaxation). Pulse is the wave of pressure in arteries, blood pressure is the force against vessel walls, and circulation is the movement of blood. Heartbeat is the correct term.
Q2. The wave of pressure that travels through the arteries when the heart beats is called:
The pulse is the rhythmic expansion and contraction of arteries caused by the pressure wave generated by the heartbeat. It can be felt as a throbbing sensation in arteries like the radial artery at the wrist. Heartbeat is the heart’s action, blood pressure is the force, and cardiac output is the volume pumped per minute.
Q3. The force exerted by blood against the walls of blood vessels is called:
Blood pressure is the force exerted by circulating blood against the walls of blood vessels. It is highest in arteries and lowest in veins. Pulse is the pressure wave, heart rate is beats per minute, and osmotic pressure is related to solute concentration. Blood pressure is the correct answer.
Q4. The higher number in a blood pressure reading (e.g., 120 in 120/80) represents:
The higher number in a blood pressure reading is the systolic pressure, which is the pressure during ventricular contraction (systole). The lower number is diastolic pressure (during relaxation). Pulse pressure is the difference between systolic and diastolic, and mean arterial pressure is the average.
Q5. The lower number in a blood pressure reading (e.g., 80 in 120/80) represents:
The lower number in a blood pressure reading is the diastolic pressure, which is the pressure in the arteries when the heart relaxes between beats (diastole). Systolic pressure is the higher number. Pulse rate and stroke volume are different measurements. Diastolic pressure is the correct answer.
Q6. The normal blood pressure for a healthy adult human is approximately:
The normal blood pressure for a healthy adult is about 120/80 mm Hg. 90/60 is low, 150/100 and 180/120 are high (hypertension). Blood pressure can vary with age, health, and activity. 120/80 is considered the ideal normal reading.
Q7. The process of removing metabolic waste products from the body is called:
Excretion is the process of removing metabolic waste products (like urea, carbon dioxide, and excess water) from the body. Digestion breaks down food, circulation transports substances, and respiration is gas exchange. Excretion is the removal of wastes.
Q8. Which of the following is not an excretory product in humans?
Oxygen is not an excretory product; it is a gas required for respiration and is taken in, not eliminated as waste. Carbon dioxide, urea, and excess water are all excretory products that need to be removed from the body to maintain homeostasis. Oxygen is used, not excreted.
Q9. In small aquatic animals like Amoeba and Paramecium, excretion occurs mainly by:
Unicellular aquatic organisms like Amoeba and Paramecium excrete waste products through their body surface by diffusion. They have no specialized excretory organs like kidneys. The large surface-area-to-volume ratio allows efficient diffusion of wastes and gases into the surrounding water.
Q10. The process by which excess water is removed from a unicellular freshwater organism like Amoeba is called:
Amoeba lives in freshwater, where water constantly enters by osmosis. The contractile vacuole pumps out excess water using active transport (energy) to prevent the cell from bursting. This is not diffusion or osmosis; it is an active process. Diffusion and osmosis are passive.
Q11. Which organ in humans is primarily responsible for excreting carbon dioxide?
Carbon dioxide is excreted primarily by the lungs during exhalation. It is a waste product of cellular respiration. The kidneys excrete urea, the skin excretes water and salts, and the liver processes waste but does not excrete CO₂ directly. The lungs are the main organ for CO₂ excretion.
Q12. The skin helps in excretion by removing:
The skin excretes water, salts (sodium chloride), and small amounts of urea in sweat. This helps regulate body temperature and remove some waste products. Carbon dioxide is excreted by the lungs, and bile pigments are excreted by the liver and intestines.
Q13. The large intestine (colon) is involved in excretion by:
The large intestine eliminates undigested food (feces) and also excretes some waste products like bile pigments (which give feces its colour). It does not filter blood (kidneys do), remove carbon dioxide (lungs do), or produce urea (liver does). It is part of the excretory system for solid wastes.
Q14. The liver is an excretory organ because it:
The liver is an excretory organ because it converts toxic ammonia into less toxic urea and excretes bile pigments (like bilirubin) into the bile. The kidneys produce urine, filter blood, and the lungs remove carbon dioxide. The liver’s role in excretion is important for nitrogen waste processing.
Q15. The main nitrogenous waste product in humans is:
The main nitrogenous waste product in humans is urea. Ammonia is toxic and is converted to urea by the liver. Uric acid is excreted by birds and reptiles, and creatinine is a waste product from muscle metabolism. Urea is the primary nitrogenous waste in humans.
Q16. The functional unit of the human kidney is the:
The nephron is the functional unit of the kidney. Each kidney contains about 1 million nephrons, which filter blood and form urine. Neurons are nerve cells, ureters carry urine, and alveoli are in the lungs. The nephron is the correct answer.
Q17. The tube that carries urine from each kidney to the urinary bladder is called:
The ureter is the tube that carries urine from each kidney to the urinary bladder. The urethra carries urine from the bladder to the outside, the nephron is the functional unit, and the collecting duct collects urine within the kidney. The ureter is the correct tube.
Q18. The muscular sac that stores urine until it is expelled from the body is the:
The urinary bladder is a muscular sac that stores urine until it is expelled. The kidneys produce urine, the ureters carry it to the bladder, and the urethra carries it out. The bladder is the storage organ. The bladder can hold about 400-500 mL of urine.
Q19. The tube that carries urine from the urinary bladder to the outside of the body is the:
The urethra is the tube that carries urine from the urinary bladder to the outside of the body. The ureter carries urine from the kidney to the bladder, the nephron is the functional unit, and the collecting duct is inside the kidney. The urethra is the exit tube.
Q20. The average amount of urine passed by a healthy adult human in 24 hours is approximately:
A healthy adult produces about 1 to 1.8 liters of urine per day. This varies with fluid intake, diet, and activity. 500 mL is too low, and 3-6 liters is too high for an average healthy person. The typical range is 1-1.8 L.
Q21. The process that artificially removes waste products from the blood when kidneys fail is called:
Dialysis is the artificial process of removing waste products and excess water from the blood when kidneys fail. It uses a machine with a semipermeable membrane (dialyzer) to filter blood. Transfusion is blood transfer, transplantation is organ replacement, and filtration is a general process.
Q22. In hemodialysis, the patient’s blood is passed through a machine containing a:
In hemodialysis, blood is passed through a dialyzer (artificial kidney) that contains a semipermeable membrane. Waste products like urea diffuse out of the blood into the dialysis fluid, while large molecules and blood cells are retained. Filter paper, centrifuges, and chemical reactors are not used.
Q23. Which part of the nephron is responsible for the actual filtration of blood?
The glomerulus is the part of the nephron where the actual filtration of blood occurs. It is a network of capillaries surrounded by Bowman’s capsule. Blood is filtered here, and the filtrate passes into the renal tubule. The loop of Henle, collecting duct, and distal tubule are involved in reabsorption and concentration, not filtration.
Q24. In the nephron, the reabsorption of glucose and most water back into the blood occurs in the:
Reabsorption of glucose, amino acids, and most water occurs in the proximal convoluted tubule of the nephron. This is where useful substances are returned to the blood. The glomerulus filters blood, the ureter carries urine, and the bladder stores urine. The renal tubule is the correct site.
Q25. The main nitrogenous waste excreted in human urine is:
The main nitrogenous waste excreted in human urine is urea. It is formed in the liver from ammonia. Uric acid is excreted by birds and reptiles, and creatinine is a smaller waste product. Urea is the primary nitrogenous waste in human urine.
Q26. The color of normal human urine is yellow due to the presence of:
The yellow color of normal urine is due to urochrome, a pigment derived from the breakdown of hemoglobin (bile pigments). Urea is colourless, bilirubin gives a darker color (in jaundice), and hemoglobin would indicate blood in urine. Urochrome is the correct pigment.
Q27. Which of the following animals excretes ammonia directly into water?
Fish excrete ammonia directly into the surrounding water because ammonia is highly toxic but can be easily diluted in water. Humans excrete urea, birds excrete uric acid, and lizards also excrete uric acid (uricotelic). Fish are ammonotelic and excrete ammonia.
Q28. Which of the following animals excretes uric acid to conserve water?
Birds and reptiles excrete uric acid as their main nitrogenous waste. Uric acid is less toxic and requires very little water to excrete, which is beneficial for conserving water in dry environments and for egg development (the embryo is not poisoned by waste). Humans excrete urea, fish excrete ammonia.
Q29. The presence of glucose in urine indicates a possible condition called:
The presence of glucose in urine (glycosuria) is a symptom of diabetes mellitus (high blood sugar). In diabetes, the kidneys cannot reabsorb all the glucose from the filtrate, so some glucose appears in urine. Kidney stones, uremia, and hypertension are different conditions.
Q30. The term for the presence of excess urea and other waste products in the blood is:
Uremia is the condition where urea and other waste products accumulate in the blood due to kidney failure. Hematuria is blood in urine, proteinuria is protein in urine, and pyuria is pus in urine. Uremia is the correct term for excess urea in the blood.
Q31. The part of the brain that controls the rate of heartbeat is the:
The medulla oblongata (brainstem) contains the cardiac center that controls the rate and force of the heartbeat. The cerebrum is for higher functions, the cerebellum coordinates movement, and the hypothalamus regulates homeostasis (temperature, hunger). The medulla oblongata controls heartbeat.
Q32. During exercise, the pulse rate increases because:
During exercise, muscles work harder and require more oxygen for cellular respiration, producing more carbon dioxide. The heart beats faster to deliver more oxygen to muscles and remove waste products. Pulse rate increases to meet the body’s increased demand for oxygen and removal of CO₂.
Q33. Which of the following correctly lists the order of structures through which urine passes after leaving the kidney?
After leaving the kidney, urine passes through the ureter to the urinary bladder, where it is stored, and then out through the urethra. This is the correct order. The other options have incorrect sequences. Urine flows in this direction: kidney → ureter → bladder → urethra.
Q34. The process by which the kidneys regulate the water and salt balance in the blood is called:
Osmoregulation is the process by which the kidneys regulate the water and salt balance in the blood, maintaining osmotic balance. Excretion is the removal of waste, filtration is the initial step, and secretion is the active transport of substances. Osmoregulation is the correct term.
Q35. The instrument used to measure blood pressure is called:
A sphygmomanometer is the instrument used to measure blood pressure. It consists of an inflatable cuff and a pressure gauge. A stethoscope is used to listen to body sounds, a thermometer measures temperature, and a pulse oximeter measures oxygen saturation. Sphygmomanometer is the correct instrument.
Q36. The maximum amount of urine that an adult human bladder can hold is approximately:
The average adult human bladder can hold about 400-500 mL of urine comfortably, with a maximum capacity of about 500-600 mL. 100 mL is too low, 1 liter is high, and 2 liters is excessive. The bladder’s capacity is about 500 mL.
Q37. In a dialysis machine, the dialysis fluid (dialysate) contains:
Dialysis fluid (dialysate) contains glucose, salts, and other substances at concentrations similar to normal blood but contains no urea. This concentration gradient allows urea and other waste products to diffuse out of the blood into the dialysate. Pure water would cause imbalances, and urea would not be removed.
Q38. Which of the following is not a function of the kidneys?
The kidneys do not digest proteins; that is the function of the digestive system (stomach, intestines). The kidneys remove urea, regulate blood pressure (through renin), and produce erythropoietin to stimulate RBC production. Digestion of proteins is not a kidney function.
Q39. The pulse can be felt most easily at which of the following arteries?
The pulse can be felt easily at the radial artery (wrist), femoral artery (thigh), and carotid artery (neck). These are common pulse points. All are correct, so “All of the above” is the answer. The radial artery is the most commonly used.
Q40. The condition of persistently high blood pressure (above 130/80 mm Hg) is called:
Hypertension is the condition of persistently high blood pressure. A reading above 130/80 mm Hg is considered hypertension. Hypotension is low blood pressure, bradycardia is slow heart rate, and tachycardia is fast heart rate. Hypertension is the correct term for high blood pressure.
Q41. The condition of low blood pressure (below 90/60 mm Hg) is called:
Hypotension is low blood pressure, defined as a reading below 90/60 mm Hg. Hypertension is high blood pressure, arrhythmia is irregular heartbeat, and ischemia is reduced blood supply. Hypotension is the correct term for low blood pressure.
Q42. In the kidney, the blood vessel that carries filtered blood away from the glomerulus is the:
The efferent arteriole carries filtered blood away from the glomerulus. The afferent arteriole carries blood into the glomerulus. The renal vein carries blood away from the kidney, and peritubular capillaries surround the tubules. The efferent arteriole is the correct vessel.
Q43. Which of the following substances is normally not found in the urine of a healthy person?
Protein is normally not found in the urine of a healthy person because it is too large to pass through the glomerular filter. Urea, sodium, and water are normal components of urine. The presence of protein in urine (proteinuria) can indicate kidney damage.
Q44. The average number of heartbeats per minute in a newborn baby is approximately:
A newborn baby’s heart rate is typically 100-160 beats per minute. This is faster than an adult’s rate (60-100 bpm). 40-60 is too slow, 70-80 is adult resting rate, and 200-220 is too high for a newborn (though possible in some conditions). 100-160 is the normal range.
Q45. The process of expelling urine from the urinary bladder is called:
Micturition is the process of expelling urine from the urinary bladder (urination). Excretion is the overall removal of wastes, filtration is the initial step in urine formation, and secretion is the active transport of substances. Micturition is the specific term for passing urine.
Q46. The main function of the collecting duct in the nephron is to:
The collecting duct carries urine from multiple nephrons to the renal pelvis. It also plays a key role in concentrating urine by reabsorbing water under the influence of ADH. It does not filter blood, reabsorb glucose (that’s in the proximal tubule), or secrete urea.
Q47. The hormone that controls how much water is reabsorbed by the kidneys (making urine concentrated or dilute) is:
Antidiuretic hormone (ADH), also called vasopressin, controls water reabsorption in the kidneys. It increases water permeability of the collecting duct, making urine more concentrated. Insulin regulates blood sugar, adrenaline is the fight-or-flight hormone, and thyroxine regulates metabolism. ADH is the correct answer.
Q48. In the human excretory system, the renal artery carries:
The renal artery carries oxygenated blood containing waste products (like urea) from the heart to the kidney for filtration. It is a branch of the aorta. The renal vein carries deoxygenated blood away from the kidney. The renal artery does not carry urine or filtered blood.
Q49. The reason why birds and reptiles excrete uric acid instead of urea is:
Birds and reptiles excrete uric acid because it is less toxic than urea and requires very little water to excrete (it is excreted as a pasty white substance). This is an adaptation to conserve water in dry environments and is also important for egg development (the embryo is not poisoned by waste). They can produce urea but choose uric acid.
Q50. If both kidneys fail completely and dialysis is not available, what is the most likely outcome?
If both kidneys fail completely, waste products (urea, creatinine) accumulate in the blood, leading to uremia. Without dialysis or a kidney transplant, the condition is fatal within days to weeks. The liver cannot take over kidney function, and the skin cannot excrete enough waste. The correct answer is that the person will develop uremia and die.