MCQs on Excretory System
Practice these GNM 1st Year Anatomy & Physiology multiple-choice questions on the excretory system. The questions cover the kidneys, nephron, urinary system, urine formation, micturition and regulation of fluid balance.
Before attempting these MCQs, review the Excretory System theory notes for GNM 1st Year and the Important Questions on Excretory System.
Excretory System MCQs – GNM 1st Year
1. What is the structural and functional unit of the kidney?
A. Alveolus
B. Nephron
C. Neuron
D. Osteon
Answer: B. Nephron
Explanation: The nephron is the structural and functional unit of the kidney and is responsible for filtering blood and forming urine.
2. How many kidneys are normally present in the human body?
A. One
B. Two
C. Three
D. Four
Answer: B. Two
Explanation: A normal human has two kidneys, located on either side of the vertebral column.
3. Which part of the kidney is the outer region?
A. Renal pelvis
B. Renal medulla
C. Renal cortex
D. Renal papilla
Answer: C. Renal cortex
Explanation: The renal cortex forms the outer portion of the kidney.
4. Which part of the kidney contains the renal pyramids?
A. Renal cortex
B. Renal medulla
C. Renal capsule
D. Renal pelvis
Answer: B. Renal medulla
Explanation: The renal medulla contains the renal pyramids through which urine drains toward the renal pelvis.
5. The glomerulus is located inside the:
A. Ureter
B. Urinary bladder
C. Bowman's capsule
D. Collecting duct
Answer: C. Bowman's capsule
Explanation: The glomerulus is a capillary network enclosed by Bowman's capsule. Together they form the renal corpuscle.
6. Which process occurs first during urine formation?
A. Tubular secretion
B. Tubular reabsorption
C. Glomerular filtration
D. Micturition
Answer: C. Glomerular filtration
Explanation: Glomerular filtration is the first major step in urine formation and occurs in the renal corpuscle.
7. Which process returns useful substances from the renal tubule to the blood?
A. Filtration
B. Reabsorption
C. Secretion
D. Micturition
Answer: B. Reabsorption
Explanation: Tubular reabsorption returns useful substances and water from tubular fluid to the blood.
8. Which process moves selected substances from blood into the renal tubule?
A. Tubular secretion
B. Glomerular filtration
C. Micturition
D. Digestion
Answer: A. Tubular secretion
Explanation: Tubular secretion transfers selected substances from the blood into the renal tubular fluid.
9. Which structure carries urine from the kidney to the urinary bladder?
A. Urethra
B. Ureter
C. Renal artery
D. Renal vein
Answer: B. Ureter
Explanation: The two ureters transport urine from the kidneys to the urinary bladder.
10. Which organ temporarily stores urine?
A. Kidney
B. Ureter
C. Urinary bladder
D. Urethra
Answer: C. Urinary bladder
Explanation: The urinary bladder is a muscular hollow organ that temporarily stores urine.
11. Which structure carries urine from the urinary bladder to the outside of the body?
A. Ureter
B. Urethra
C. Renal pelvis
D. Nephron
Answer: B. Urethra
Explanation: The urethra is the tube through which urine leaves the urinary bladder.
12. What is the process of emptying the urinary bladder called?
A. Filtration
B. Absorption
C. Micturition
D. Secretion
Answer: C. Micturition
Explanation: Micturition is the process of expelling urine from the urinary bladder.
13. Which muscle forms most of the muscular wall of the urinary bladder?
A. Diaphragm
B. Detrusor muscle
C. Masseter
D. Intercostal muscle
Answer: B. Detrusor muscle
Explanation: The detrusor muscle forms most of the bladder wall and contracts during bladder emptying.
14. Which hormone promotes water reabsorption in the kidney?
A. Insulin
B. Thyroxine
C. Antidiuretic hormone
D. Glucagon
Answer: C. Antidiuretic hormone
Explanation: ADH increases water reabsorption in parts of the renal collecting system and helps regulate urine concentration.
15. Which hormone promotes sodium reabsorption in the distal nephron?
A. Aldosterone
B. Insulin
C. Melatonin
D. Calcitonin
Answer: A. Aldosterone
Explanation: Aldosterone promotes sodium reabsorption and increases potassium secretion in the distal nephron.
16. Which structure is part of the renal corpuscle?
A. Loop of Henle
B. Collecting duct
C. Glomerulus
D. Ureter
Answer: C. Glomerulus
Explanation: The renal corpuscle consists of the glomerulus and Bowman's capsule.
17. Which part of the nephron is mainly involved in reabsorbing a large amount of filtered water and useful substances?
A. Proximal convoluted tubule
B. Ureter
C. Renal pelvis
D. Urethra
Answer: A. Proximal convoluted tubule
Explanation: The proximal convoluted tubule reabsorbs a large proportion of filtered water and important substances such as glucose, amino acids and electrolytes.
18. Which structure extends into the renal medulla and contributes to urine concentration?
A. Loop of Henle
B. Bowman's capsule
C. Renal pelvis
D. Ureter
Answer: A. Loop of Henle
Explanation: The loop of Henle extends into the renal medulla and contributes to the kidney's ability to concentrate urine.
19. Which structure receives tubular fluid from nephrons?
A. Collecting duct
B. Renal artery
C. Ureter
D. Renal vein
Answer: A. Collecting duct
Explanation: Collecting ducts receive fluid from nephrons and carry it toward the renal papilla.
20. Which of the following is a major function of the kidneys?
A. Production of bile
B. Removal of metabolic wastes
C. Production of digestive enzymes
D. Absorption of food
Answer: B. Removal of metabolic wastes
Explanation: The kidneys remove metabolic waste products from the blood and excrete them in urine.
21. Which substance is normally the major component of urine?
A. Water
B. Protein
C. Fat
D. Red blood cells
Answer: A. Water
Explanation: Normal urine consists mainly of water along with dissolved waste products and electrolytes.
22. Which of the following is a nitrogenous waste product found in urine?
A. Urea
B. Oxygen
C. Haemoglobin
D. Insulin
Answer: A. Urea
Explanation: Urea is a major nitrogenous waste product excreted by the kidneys.
23. Which hormone is produced by the kidneys and supports red blood cell production?
A. Erythropoietin
B. Insulin
C. Thyroxine
D. Growth hormone
Answer: A. Erythropoietin
Explanation: The kidneys produce erythropoietin, which stimulates red blood cell production in the bone marrow.
24. Which organ activates vitamin D as part of its endocrine function?
A. Kidney
B. Stomach
C. Spleen
D. Pancreas
Answer: A. Kidney
Explanation: The kidneys convert vitamin D to its biologically active form, which is important for calcium and bone metabolism.
25. Urine moves through the ureters mainly by:
A. Diffusion
B. Peristalsis
C. Filtration
D. Osmosis only
Answer: B. Peristalsis
Explanation: Rhythmic muscular contractions called peristalsis help propel urine through the ureters toward the bladder.
26. Which of the following is NOT a major process of urine formation?
A. Glomerular filtration
B. Tubular reabsorption
C. Tubular secretion
D. Digestion
Answer: D. Digestion
Explanation: Digestion is a function of the digestive system, not a process of urine formation.
27. The renal pelvis primarily functions to:
A. Filter blood
B. Collect urine
C. Store urine permanently
D. Produce red blood cells
Answer: B. Collect urine
Explanation: The renal pelvis is a funnel-shaped structure that collects urine before it enters the ureter.
28. Which system helps the kidneys regulate blood pressure through renin and related hormones?
A. Renin-angiotensin-aldosterone system
B. Digestive system
C. Respiratory system
D. Skeletal system
Answer: A. Renin-angiotensin-aldosterone system
Explanation: The renin-angiotensin-aldosterone system contributes to regulation of blood pressure and fluid balance.
29. Which of the following is an important nursing observation related to the urinary system?
A. Urine output
B. Hair length
C. Nail colour only
D. Height
Answer: A. Urine output
Explanation: Urine output can provide important information about hydration, kidney function and a patient's clinical condition when interpreted in context.
30. Which sequence correctly represents the three major processes of urine formation?
A. Secretion → digestion → filtration
B. Filtration → reabsorption → secretion
C. Reabsorption → digestion → filtration
D. Micturition → filtration → digestion
Answer: B. Filtration → reabsorption → secretion
Explanation: Urine formation involves glomerular filtration followed by tubular reabsorption and tubular secretion.
Quick Revision
- Functional unit: Nephron
- Outer kidney: Renal cortex
- Inner kidney: Renal medulla
- First step of urine formation: Glomerular filtration
- Useful substances returned to blood: Tubular reabsorption
- Selected substances moved into tubule: Tubular secretion
- Kidney to bladder: Ureter
- Urine storage: Urinary bladder
- Bladder to outside: Urethra
- Bladder emptying: Micturition
- Water reabsorption hormone: ADH
- Sodium-retaining hormone: Aldosterone
Related Study Resources
For detailed explanations, read the Excretory System theory notes.
For examination preparation, practise the Important Questions on Excretory System.