Notes on Human Glomerulus: Structure and Function, Urinary System, Excretory System MCQ with Answer

Structure of Glomerulus

The glomerulus is a network of capillaries located at the beginning of a nephron in the kidney. It is enclosed within a Bowman’s capsule and plays a crucial role in the process of urine formation.

Key structural components:

• Afferent arteriole: Brings blood into the glomerulus.

• Capillary tuft: A cluster of capillaries where filtration occurs.

• Efferent arteriole: Carries blood away from the glomerulus.

• Bowman’s capsule: A cup-like sac that surrounds the glomerulus and collects the filtrate.

• Podocytes: Specialized cells lining the inner layer of the Bowman’s capsule, helping with filtration.

• Basement membrane: A semipermeable structure that acts as a barrier and filter.

Function of the Glomerulus

The primary function of the glomerulus is filtration of blood. It initiates the process of urine formation through:

1. Ultrafiltration:

   • Blood pressure forces plasma minus large proteins and cells through the glomerular membrane into Bowman’s capsule.

   • This fluid is called glomerular filtrate.

2. Selective Permeability:

   • Allows water, glucose, salts, amino acids, and urea to pass through.

   • Retains large molecules like proteins and blood cells.

3. Filtration Rate:

   • The rate at which the glomerulus filters blood is known as the glomerular filtration rate (GFR).

   • Normal GFR is about 125 mL/min in adults.

1. Where is the glomerulus located?
   a) In the liver
   b) In the nephron of the kidney
   c) In the heart
   d) In the urinary bladder
   Answer: b

2. What is the function of the glomerulus?
   a) Reabsorption
   b) Secretion
   c) Filtration
   d) Excretion
   Answer: c

3. Which arteriole brings blood into the glomerulus?
   a) Efferent arteriole
   b) Renal vein
   c) Afferent arteriole
   d) Peritubular capillaries
   Answer: c

4. What type of pressure drives filtration in the glomerulus?
   a) Osmotic pressure
   b) Oncotic pressure
   c) Hydrostatic pressure
   d) Atmospheric pressure
   Answer: c

5. Which structure collects the filtrate from the glomerulus?
   a) Loop of Henle
   b) Bowman’s capsule
   c) Proximal tubule
   d) Renal pelvis
   Answer: b

6. What does not pass through the glomerular filtration barrier?
   a) Glucose
   b) Water
   c) Proteins
   d) Urea
   Answer: c

7. Podocytes are found in which part of the nephron?
   a) Collecting duct
   b) Bowman’s capsule
   c) Loop of Henle
   d) Distal tubule
   Answer: b

8. What is the normal GFR in healthy adults?
   a) 60 mL/min
   b) 90 mL/min
   c) 125 mL/min
   d) 200 mL/min
   Answer: c

9. Which arteriole is smaller in diameter in the glomerulus?
   a) Afferent arteriole
   b) Efferent arteriole
   Answer: b

10. The glomerular basement membrane is mainly responsible for filtering based on:
    a) Size and charge
    b) Color
    c) Temperature
    d) Speed of flow
    Answer: a