Disorders & Other Excretory Organs — NEET Biology MCQs with Solutions
Free NEET Biology Disorders & Other Excretory Organs MCQs with step-by-step solutions (57 questions). Part of Excretory Products and Their Elimination. Practise online on Prepizo — no login needed.
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Questions with solutions
Q1 — Disorders & Other Excretory Organs · easy · theory
The artificial process used to remove nitrogenous wastes from the blood of kidney-failure patients is:
A. Filtration by liver
B. Transfusion
C. Transpiration
D. Haemodialysis ✓ Correct
Solution: Haemodialysis uses an artificial kidney to filter urea/wastes from the blood when kidneys fail.
Q2 — Disorders & Other Excretory Organs · easy · theory
The accumulation of urea in the blood due to kidney malfunction is called:
A. Anaemia
B. Glycosuria
C. Uremia ✓ Correct
D. Diabetes
Solution: Uremia is a high blood urea level from kidney failure; it can be treated by dialysis.
Q3 — Disorders & Other Excretory Organs · medium · theory
The sweat and sebaceous glands of the skin assist in excretion by removing:
A. Only carbon dioxide
B. Small amounts of salts, urea, lactic acid (and sebum) ✓ Correct
C. Blood cells
D. Only glucose
Solution: Sweat glands excrete water, salts and small amounts of urea/lactate; sebaceous glands remove sterols and waxes.
Q4 — Disorders & Other Excretory Organs · medium · theory
In humans, the lungs act as accessory excretory organs by removing:
A. Bile pigments
B. Urea
C. CO₂ and some water vapour ✓ Correct
D. Uric acid
Solution: The lungs excrete large amounts of CO₂ and some water vapour with each breath.
Q5 — Disorders & Other Excretory Organs · hard · theory
Kidney stones (renal calculi) are:
A. Insoluble crystallised masses (e.g. of oxalates) formed in the kidney ✓ Correct
B. Clots of blood cells
C. Excess plasma proteins
D. Deposits of glucose
Solution: Renal calculi are hard crystalline stones (often calcium oxalate) that can obstruct the urinary tract.
Q6 — Disorders & Other Excretory Organs · hard · theory
Kidney transplantation is the ultimate treatment for acute renal failure; the donor kidney is ideally taken from:
A. A close relative to minimise immune rejection ✓ Correct
B. Any unrelated person
C. The patient's own failed kidney
D. An animal
Solution: A genetically close (matched) donor reduces the risk of immune rejection in transplantation.
Q7 — Disorders & Other Excretory Organs · easy · numerical
In an artificial kidney (haemodialysis) unit, the composition of the dialysing fluid is similar to that of plasma except that it:
A. Contains a very high concentration of urea
B. Lacks all glucose and mineral ions
C. Contains no nitrogenous wastes such as urea ✓ Correct
D. Is made up of pure distilled water only
Solution: The dialysing fluid matches plasma in ions and glucose but has no nitrogenous wastes, so urea and other wastes diffuse out of the blood into the fluid while useful substances are retained.
Q8 — Disorders & Other Excretory Organs · easy · numerical
Inflammation of the glomeruli of the kidney is medically termed:
A. Uremia
B. Glomerulonephritis ✓ Correct
C. Renal calculi
D. Cystitis
Solution: Glomerulonephritis is inflammation of the glomeruli, which impairs filtration; uremia is raised blood urea and renal calculi are kidney stones.
Q9 — Disorders & Other Excretory Organs · easy · numerical
Deposition of uric acid crystals in the joints, causing painful inflammation, results in the condition called:
A. Glomerulonephritis
B. Gout ✓ Correct
C. Uremia
D. Diabetes insipidus
Solution: Excess uric acid can crystallise in the joints and produce gout; this is distinct from uremia (blood urea build-up) and renal calculi (stones).
Q10 — Disorders & Other Excretory Organs · easy · numerical
Besides bile pigments, the liver contributes to excretion by removing from the blood substances such as:
A. Large amounts of sodium chloride through sweat
B. Cholesterol, degraded steroid hormones, vitamins and certain drugs ✓ Correct
C. Carbon dioxide and water vapour
D. Excess glucose directly into the urine
Solution: The liver eliminates cholesterol, inactivated steroid hormones, some vitamins and many drugs (along with bile pigments from haemoglobin breakdown) via the bile.
Q11 — Disorders & Other Excretory Organs · medium · numerical
Match each accessory excretory organ with the material it chiefly removes: (i) Lungs (ii) Liver (iii) Sweat glands (iv) Sebaceous glands — with (p) CO₂ and water vapour (q) bile pigments and cholesterol (r) NaCl, water, some urea and lactic acid (s) sterols and waxes (sebum).
A. (i)-q, (ii)-p, (iii)-s, (iv)-r
B. (i)-r, (ii)-s, (iii)-p, (iv)-q
C. (i)-p, (ii)-r, (iii)-q, (iv)-s
D. (i)-p, (ii)-q, (iii)-r, (iv)-s ✓ Correct
Solution: Lungs remove CO₂ and water vapour, the liver removes bile pigments and cholesterol, sweat glands remove NaCl/water/urea/lactic acid, and sebaceous glands remove sterols and waxes.
Q12 — Disorders & Other Excretory Organs · medium · numerical
During haemodialysis of a uremic patient, the blood drawn out is mixed with an anticoagulant such as heparin. Why is heparin added and then dealt with before the blood is returned?
A. It destroys plasma proteins, which are then replaced by fresh plasma
B. It removes urea from the blood, and it is later reabsorbed by the kidney
C. It prevents the blood from clotting in the machine, and it is neutralised by adding heparinase before returning the blood ✓ Correct
D. It concentrates the blood, and it is diluted with saline before returning
Solution: Heparin is added to stop the blood clotting as it passes through the dialyser; before the cleared blood is returned to the patient the anticoagulant is neutralised (heparinase is added).
Q13 — Disorders & Other Excretory Organs · medium · numerical
Assertion (A): Renal calculi (kidney stones) can obstruct urine flow and cause severe pain. Reason (R): Kidney stones are insoluble masses of crystallised salts such as calcium oxalate that form within the kidney. Choose the correct option.
A. A is false but R is true
B. Both A and R are true but R is NOT the correct explanation of A
C. Both A and R are true and R is the correct explanation of A ✓ Correct
D. A is true but R is false
Solution: Kidney stones are hard, insoluble crystals (often calcium oxalate) formed in the kidney; being solid masses they can block the urinary passage and cause intense pain, so R explains A.
Q14 — Disorders & Other Excretory Organs · medium · numerical
Which of the following statements about kidney (renal) failure is INCORRECT?
A. Failure of the kidneys leads to accumulation of urea and other wastes in the blood
B. In renal failure the glomerular filtration rate rises sharply above normal ✓ Correct
C. Kidney transplantation is the ultimate corrective measure for severe renal failure
D. Renal failure may be treated by haemodialysis using an artificial kidney
Solution: In renal failure the GFR falls, not rises, so wastes accumulate in the blood (uremia); dialysis and transplantation are the standard treatments.
Q15 — Disorders & Other Excretory Organs · medium · numerical
Which of the following statements about the excretory role of the skin is correct?
A. Sweat glands secrete bile pigments produced from haemoglobin breakdown
B. Sebaceous glands are the chief route for removing carbon dioxide from the body
C. Sweat glands excrete NaCl, water, small amounts of urea and lactic acid, mainly for cooling with a minor excretory role ✓ Correct
D. The skin removes more nitrogenous waste than the kidneys do
Solution: Sweat glands excrete water, NaCl, small amounts of urea and lactic acid; their primary function is thermoregulation, with excretion being a secondary role.
Q16 — Disorders & Other Excretory Organs · medium · numerical
A patient shows a high blood urea level, and doctors decide to filter the blood through a membrane immersed in a plasma-like fluid lacking wastes. The disorder being managed and the technique used are, respectively:
A. Diabetes insipidus and ultrafiltration
B. Gout and kidney transplantation
C. Uremia and haemodialysis ✓ Correct
D. Glomerulonephritis and micturition
Solution: A raised blood urea level is uremia; passing the blood through a dialyser (membrane in waste-free dialysing fluid) to remove the urea is haemodialysis.
Q17 — Disorders & Other Excretory Organs · easy
The expulsion of urine from the urinary bladder is called:
A. Micturition ✓ Correct
B. Uremia
C. Anuria
D. Uricolysis
Solution: The process of release/expulsion of urine from the urinary bladder is called micturition, and the neural mechanisms causing it constitute the micturition reflex.
Q18 — Disorders & Other Excretory Organs · medium
During micturition, which of the following occurs?
A. Ureter relaxes
B. Ureter contracts
C. Urethral sphincter relaxes ✓ Correct
D. Urethra contracts
Solution: In micturition, the smooth muscles of the bladder contract and the urethral sphincter relaxes, allowing urine to be expelled through the urethra.
Q19 — Disorders & Other Excretory Organs · medium
The principal events of urination are given below in an unordered manner: I. Stretch receptors on the wall of the urinary bladder send signals to the CNS. II. The bladder fills with urine and becomes distended. III. Micturition. IV. CNS passes on motor messages to initiate contraction of smooth muscles of the bladder and simultaneous relaxation of the urethral sphincter. The correct order of steps for urination is:
A. III, II, I, IV
B. I, II, III, IV
C. II, I, IV, III ✓ Correct
D. IV, III, II, I
Solution: The bladder first fills and distends (II), stretch receptors then signal the CNS (I), the CNS sends motor messages to contract the bladder and relax the sphincter (IV), leading to micturition (III).
Q20 — Disorders & Other Excretory Organs · easy
The neural mechanism causing urination is called:
A. Micturition reflex ✓ Correct
B. Scarth reflex
C. None
D. Withdrawal reflex
Solution: The neural mechanisms causing urination are together called the micturition reflex.
Q21 — Disorders & Other Excretory Organs · easy
The average pH of human urine is approximately:
A. 6 ✓ Correct
B. 3
C. 9
D. 7
Solution: Human urine is slightly acidic, with an average pH of about 6.
Q22 — Disorders & Other Excretory Organs · medium
Match Column I with Column II. A. Uremia; B. Ketonuria; C. Glycosuria; D. Blood dialyser; E. Concentration of urine. I. Henle's loop; II. Ketone bodies in urine; III. Artificial kidney; IV. Glucose in urine; V. Accumulation of urea in blood.
A. A-I, B-II, C-IV, D-III, E-V
B. A-I, B-II, C-IV, D-V, E-III
C. A-V, B-II, C-IV, D-III, E-I ✓ Correct
D. A-III, B-II, C-IV, D-I, E-V
Solution: Uremia is accumulation of urea in blood (V), ketonuria is ketone bodies in urine (II), glycosuria is glucose in urine (IV), blood dialyser is the artificial kidney (III), and concentration of urine is achieved by Henle's loop (I).
Q23 — Disorders & Other Excretory Organs · medium
Diabetes mellitus is characterized by:
A. Anuria
B. Haematuria
C. Oliguria
D. Ketonuria and glycosuria ✓ Correct
Solution: In diabetes mellitus, excess glucose appears in urine (glycosuria) and ketone bodies are also excreted in urine (ketonuria).
Q24 — Disorders & Other Excretory Organs · easy
How much urea is excreted per day by a normal adult?
A. 0 g
B. 50 g
C. 1 – 2 g
D. 25 – 30 g ✓ Correct
Solution: A normal adult human excretes about 25–30 g of urea per day.
Q25 — Disorders & Other Excretory Organs · easy
Other than the kidneys, which of the following also help in the elimination of excretory wastes?
A. Liver
B. All ✓ Correct
C. Lungs
D. Skin
Solution: Besides kidneys, the lungs, liver and skin all assist in eliminating excretory wastes (CO2 by lungs; bile pigments by liver; sweat and sebum by skin).
Q26 — Disorders & Other Excretory Organs · medium
How much CO2 is removed per minute by our lungs?
A. 18 mL
B. 200 mL ✓ Correct
C. 8 L
D. 1 L
Solution: The lungs remove large amounts of CO2 (about 200 mL per minute) along with significant quantities of water.
Q27 — Disorders & Other Excretory Organs · medium
Which of the following statements is false?
A. Cholesterol is excreted in the bile and waxes are excreted in the sebum
B. 8 L urine is excreted per day ✓ Correct
C. Micturition is carried out by a reflex
D. The primary function of sweat is excretion
Solution: A normal adult excretes only about 1–1.5 L of urine per day, not 8 L, so this statement is false.
Q28 — Disorders & Other Excretory Organs · medium
The liver (largest gland) is both a secretory and an excretory organ. It secretes bile. Which of the following are major excretory products of bile?
A. Degraded and steroid hormones
B. Vitamins and drugs
C. Cholesterol
D. Bilirubin and Biliverdin ✓ Correct
Solution: The bile pigments bilirubin and biliverdin, formed from the breakdown of haemoglobin, are the major excretory products carried in bile.
Q29 — Disorders & Other Excretory Organs · easy
Most of the excretory products of bile ultimately pass out along with:
A. Urea
B. Sweat
C. Urine
D. Digestive wastes ✓ Correct
Solution: Bile pigments and other bile excretory products are passed into the intestine and are eliminated along with the digestive wastes (faeces).
Q30 — Disorders & Other Excretory Organs · hard
Consider the following statements: I. The human skin possesses sweat and sebaceous glands which eliminate some wastes in their secretion. II. Sweat is a waxy protective secretion having sterols, hydrocarbons and fatty acids. III. Sebum is an aqueous fluid having NaCl, lactic acid, urea, amino acids and glucose. Which one of the above statements is correct?
A. I and II
B. Only II
C. Only I ✓ Correct
D. II and III
Solution: Only statement I is correct. The descriptions in II and III are swapped: sweat is an aqueous fluid containing NaCl, urea, lactic acid, etc., while sebum is the waxy secretion with sterols, hydrocarbons and fatty acids.