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Important Questions & Answers

This question set covers the important examination topics from the Excretory System for GNM 1st Year Anatomy & Physiology. Prepare the answers according to the marks allotted and revise the key points before the examination.

For a complete understanding of the topic, first read the Excretory System theory notes for GNM 1st Year.

Long Answer Questions – 10 Marks

1. Describe the structure and functions of the kidney.

Answer: The kidneys are paired, bean-shaped organs located in the posterior abdominal region on either side of the vertebral column. The right kidney is usually slightly lower than the left.

Each kidney has an outer renal cortex and an inner renal medulla. The medulla contains renal pyramids, which drain urine toward the renal pelvis. The renal pelvis collects urine and continues as the ureter.

The kidney performs several important functions:

• Removes metabolic waste products from the blood.
• Forms and excretes urine.
• Regulates water and electrolyte balance.
• Helps maintain acid-base balance.
• Contributes to blood pressure regulation.
• Produces erythropoietin.
• Activates vitamin D.

2. Describe the nephron and explain its functions.

Answer: The nephron is the structural and functional unit of the kidney. It consists of a renal corpuscle and a renal tubule.

The renal corpuscle consists of the glomerulus and Bowman's capsule. The renal tubule includes the proximal convoluted tubule, loop of Henle and distal convoluted tubule. The tubular system connects with a collecting duct.

The nephron performs three major processes involved in urine formation:

• Glomerular filtration
• Tubular reabsorption
• Tubular secretion

3. Explain the process of urine formation.

Answer: Urine formation occurs in the nephrons and involves three major processes.

Glomerular filtration: Water and small dissolved substances pass from the blood through the glomerular filtration barrier into Bowman's capsule.

Tubular reabsorption: Useful substances and much of the filtered water are returned from the renal tubules to the blood.

Tubular secretion: Selected substances are transferred from the blood into the renal tubule for elimination and regulation of the body's internal environment.

4. Describe the urinary system and explain the functions of its organs.

Answer: The urinary system consists of two kidneys, two ureters, the urinary bladder and the urethra.

• Kidneys: Form urine and regulate water, electrolytes and acid-base balance.
• Ureters: Carry urine from the kidneys to the urinary bladder.
• Urinary bladder: Stores urine temporarily.
• Urethra: Carries urine from the bladder to the outside of the body.

5. Explain the role of the kidneys in maintaining homeostasis.

Answer: The kidneys help maintain the internal environment of the body by regulating water balance, electrolytes and acid-base status. They also remove metabolic waste products and contribute to blood pressure regulation.

The kidneys have endocrine functions as well. They produce erythropoietin, which supports red blood cell production, and activate vitamin D, which is important for calcium and bone metabolism.

Short Answer Questions – 5 Marks

1. What is the excretory system?

Answer: The excretory system consists of organs that remove metabolic waste products from the body and help maintain the internal environment. The kidneys are the major organs involved in urinary excretion.

2. What is a nephron?

Answer: A nephron is the structural and functional unit of the kidney. It filters blood and modifies the filtrate through filtration, reabsorption and secretion to form urine.

3. Write the main parts of a nephron.

Answer: The main parts are:

• Glomerulus
• Bowman's capsule
• Proximal convoluted tubule
• Loop of Henle
• Distal convoluted tubule
• Collecting duct

4. What is glomerular filtration?

Answer: Glomerular filtration is the first major step in urine formation. Water and small dissolved substances pass from the blood through the filtration barrier of the glomerulus into Bowman's capsule.

5. What is tubular reabsorption?

Answer: Tubular reabsorption is the movement of useful substances and water from the renal tubular fluid back into the blood.

6. What is tubular secretion?

Answer: Tubular secretion is the transfer of selected substances from the blood into the renal tubule. It contributes to waste removal and regulation of electrolyte and acid-base balance.

7. Write the functions of the kidneys.

Answer:

• Excretion of metabolic wastes
• Formation of urine
• Regulation of water balance
• Regulation of electrolytes
• Maintenance of acid-base balance
• Contribution to blood pressure regulation
• Production of erythropoietin
• Activation of vitamin D

8. What are the functions of the ureters?

Answer: The ureters are muscular tubes that carry urine from the kidneys to the urinary bladder. Urine is propelled mainly by rhythmic muscular contractions called peristalsis.

9. What is the urinary bladder?

Answer: The urinary bladder is a hollow muscular organ that temporarily stores urine. Its muscular wall contains the detrusor muscle, which participates in bladder emptying.

10. What is micturition?

Answer: Micturition is the process of emptying the urinary bladder through the urethra. It involves coordinated contraction of the detrusor muscle and relaxation of the urinary sphincters.

11. What is the role of ADH in the kidney?

Answer: Antidiuretic hormone (ADH) increases water reabsorption in parts of the renal collecting system. It therefore helps regulate body water balance and urine concentration.

12. What is the role of aldosterone?

Answer: Aldosterone promotes sodium reabsorption in the distal nephron and increases potassium secretion. It contributes to regulation of fluid balance and blood pressure.

Very Short Answer Questions

1. Name the structural and functional unit of the kidney.
   Nephron.
2. How many kidneys does a normal person have?
   Two.
3. What is the outer part of the kidney called?
   Renal cortex.
4. What is the inner part of the kidney called?
   Renal medulla.
5. What is the cup-shaped structure surrounding the glomerulus?
   Bowman's capsule.
6. What is the capillary network inside Bowman's capsule called?
   Glomerulus.
7. Name the tube carrying urine from the kidney to the bladder.
   Ureter.
8. Where is urine temporarily stored?
   Urinary bladder.
9. Which tube carries urine outside the body?
   Urethra.
10. What is the process of emptying the urinary bladder called?
    Micturition.
11. Name the hormone that promotes water reabsorption in the kidney.
    Antidiuretic hormone (ADH).
12. Name the three major processes involved in urine formation.
    Glomerular filtration, tubular reabsorption and tubular secretion.
13. Which muscle forms most of the muscular wall of the urinary bladder?
    Detrusor muscle.
14. Which organ produces erythropoietin?
    Kidneys.
15. Which organ activates vitamin D?
    Kidneys.

Diagram-Based Questions

Practice drawing and labelling the following diagrams for examination:

1. Structure of the kidney
2. Internal structure of the kidney
3. Nephron
4. Urinary system
5. Urine formation through the nephron

Important labels for the kidney diagram: renal cortex, renal medulla, renal pyramid, renal pelvis, renal hilum and ureter.

Important labels for the nephron diagram: glomerulus, Bowman's capsule, proximal convoluted tubule, loop of Henle, distal convoluted tubule and collecting duct.

Important Questions to Prepare First

If your examination time is limited, prepare these topics first:

1. Structure and functions of the kidney
2. Structure of the nephron
3. Process of urine formation
4. Functions of the urinary system
5. Glomerular filtration, tubular reabsorption and tubular secretion
6. Role of ADH and aldosterone
7. Urinary bladder and micturition
8. Functions of the kidneys in maintaining homeostasis
9. Kidney and nephron diagrams with proper labelling

Exam Writing Tips

• Begin long answers with a clear definition or introduction.
• Use headings and subheadings to organize your answer.
• Write the functions in numbered or bullet points.
• Draw a neat, labelled diagram whenever appropriate.
• For urine formation, remember the sequence: filtration → reabsorption → secretion.
• Underline important anatomical terms when writing a handwritten examination answer.
• For a 5-mark answer, avoid writing an unnecessarily long essay; focus on the points asked in the question.

Quick Revision

• Kidneys are the major organs of the urinary system.
• The nephron is the structural and functional unit of the kidney.
• The renal corpuscle consists of the glomerulus and Bowman's capsule.
• Urine formation involves filtration, reabsorption and secretion.
• Ureters carry urine from the kidneys to the bladder.
• The urinary bladder stores urine.
• The urethra carries urine outside the body.
• ADH promotes water reabsorption.
• Aldosterone promotes sodium reabsorption and potassium secretion.
• The kidneys help regulate water, electrolytes, acid-base balance and blood pressure.

Related Study Resources

Review the complete Excretory System theory notes for GNM 1st Year before attempting these questions.

After revision, test your preparation with the MCQs on Excretory System for GNM 1st Year.

Disclaimer

This material is provided for educational purposes for GNM students. It is not a substitute for professional medical advice, diagnosis or treatment. Patient-specific clinical decisions should be made by an appropriately qualified healthcare professional.