Answers and bookmarks are saved in this browser, across visits. They do not sync to your account.
100 questions in this collection · Page 3 of 10
Question 21 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Regarding the physiology of the micturition reflex, consider the following statements:
I. Urine formed by the nephrons is stored in the urinary bladder till a voluntary signal is given by the central nervous system (CNS). II. The micturition reflex is initiated by the contraction of smooth muscles of the bladder wall. III. In response to filling, stretch receptors on the walls of the bladder send signals to the CNS. IV. The CNS motor messages initiate contraction of smooth muscles of the bladder and simultaneous relaxation of the urethral sphincter.
Statement I is correct because urine is stored in the urinary bladder until voluntary CNS control initiates micturition. Statement II is incorrect because the reflex begins with stretching of the bladder wall, not its contraction. Statements III and IV are correct because stretch receptors activate the CNS, which coordinates bladder contraction and urethral sphincter relaxation.
Question 22 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Which of the following statements about the chemical and physical properties of normal human urine are correct?
I. An adult human excretes, on average, 1 to 1.5 litres of urine per day. II. Normal human urine is a light yellow-coloured watery fluid which is slightly alkaline, having a pH of 7.4. III. On average, 25–30 g of urea is excreted out per day. IV. Presence of glucose (glycosuria) and ketone bodies (ketonuria) in urine are indicative of diabetes mellitus.
Statement I is correct because an adult normally excretes about 1–1.5 L of urine daily. Statement II is incorrect because normal urine is slightly acidic (average pH about 6.0), not alkaline. Statements III and IV are correct because 25–30 g of urea is excreted daily and glycosuria with ketonuria are indicators of diabetes mellitus.
Question 23 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Analyze these statements concerning the excretory roles of lungs, liver, and skin:
I. Our lungs remove large amounts of CO2 (approximately 200 mL/minute) and significant quantities of water daily. II. The liver is the largest gland in our body. III. The liver secretes bile containing substances like bilirubin, biliverdin, cholesterol, degraded steroid hormones, vitamins, and drugs. IV. Most of the liver's excretory substances ultimately pass out of the body along with urine.
Statements I, II, and III are correct. Statement IV is incorrect because most bile pigments and other excretory substances leave the body through the digestive tract with faeces rather than urine.
Question 24 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Read the statements below regarding human skin and salivary excretions:
I. Sweat produced by the sweat glands is a watery fluid containing NaCl, small amounts of urea, and lactic acid. II. The primary function of sweat is to facilitate a cooling effect on the body surface. III. Sebaceous glands eliminate certain substances like sterols, hydrocarbons, and waxes through sebum. IV. Small amounts of nitrogenous wastes can never be eliminated through saliva.
Statements I, II, and III are correct. Statement IV is incorrect because small quantities of nitrogenous wastes can also be eliminated through saliva.
Question 25 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Consider the following statements about uremia and hemodialysis:
I. Malfunctioning of kidneys can lead to accumulation of urea in blood, a condition called uremia. II. During hemodialysis, blood drained from a convenient vein is pumped into a dialysing unit after adding heparin. III. The dialysing fluid has the exact same composition as plasma, except that it lacks nitrogenous wastes. IV. The cleared blood is pumped back to the body through a vein after adding anti-heparin.
Statement I is correct because accumulation of urea in blood due to kidney malfunction is called uremia. Statement II is incorrect because blood is withdrawn from a convenient artery, not a vein, before dialysis. Statement III is correct because the dialysing fluid has the same composition as plasma except for nitrogenous wastes. Statement IV is correct because the purified blood is returned through a vein after adding anti-heparin.
Question 26 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Examine the physiological characteristics of nitrogenous waste excretion in different organisms:
I. Aquatic insects and bony fishes lack kidneys and primarily excrete ammonium ions across body or gill surfaces. II. Inside the liver of ureotelic animals, metabolic ammonia is biochemically converted into urea. III. Marine fishes are strictly ammonotelic because they live in a highly saline environment. IV. Land snails and reptiles convert their nitrogenous waste into highly toxic urea to minimize water loss.
Statement I is correct because aquatic insects and bony fishes are ammonotelic and excrete ammonia mainly across the body surface or gills. Statement II is correct because ureotelic animals convert ammonia into urea in the liver. Statement III is incorrect because marine fishes are ureotelic. Statement IV is incorrect because land snails and reptiles are uricotelic and excrete uric acid, not urea.
Question 27 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Study these statements regarding animal excretory organs and their precise functions:
I. Flame cells or protonephridia are primarily involved in osmoregulation (ionic and fluid volume regulation). II. Annelids possess tubular structures called nephridia that help in nitrogenous waste removal and ionic balance. III. Malpighian tubules in cockroaches play a key role in the removal of nitrogenous wastes and osmoregulation. IV. Antennal glands (green glands) are complex renal organs found in all terrestrial arachnids.
Statements I, II and III are correct. Statement IV is incorrect because antennal (green) glands occur in crustaceans such as prawns, not in terrestrial arachnids.
Question 28 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Evaluate the anatomical details concerning the location and dimensions of the human kidney:
I. The human kidneys lie retroperitoneally, close to the dorsal inner wall of the abdominal cavity. II. Each kidney of an adult human weighs approximately 120–170 g. III. The kidneys are situated between the levels of the last cervical and third lumbar vertebrae. IV. A kidney measures about 10–12 cm in length and 5–7 cm in width.
Statements I, II and IV are correct. Statement III is incorrect because the kidneys lie between the last thoracic (T12) and third lumbar (L3) vertebrae, not the last cervical vertebra.
Question 29 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Anatomical features surrounding the renal hilum and pelvis are described below:
I. The renal capsule is a tough outer protective layer covering the kidney. II. Through the hilum, located on the outer convex margin, the renal artery and nerves enter the kidney. III. Inside the hilum is a broad, funnel-shaped space called the renal pelvis. IV. Calyces are projections extending from the broad renal pelvis.
Statement I is correct because the kidney is enclosed by a tough fibrous capsule. Statement II is incorrect because the hilum is situated on the inner concave surface. Statements III and IV are correct because the renal pelvis is a funnel-shaped cavity that gives rise to calyces.
Question 30 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Consider the internal tissue architecture of the human kidney:
I. The renal cortex forms the outer zone, while the renal medulla forms the inner zone. II. Medullary pyramids are conical masses that project into the renal calyces. III. The Columns of Bertini are extensions of the medulla that project into the cortical zones. IV. Both cortical and medullary tissues contain an equal distribution of glomeruli.
Which statements are incorrect?
Statements I and II are correct. Statement III is incorrect because the Columns of Bertini are cortical extensions projecting between the medullary pyramids. Statement IV is incorrect because glomeruli are found only in the cortex.