6.4.9 The Structure of the Nephron

Kidney Structure:

1. Fibrous Capsule:

• The outer layer of the kidney that protects it from damage and infection.

2. Cortex:

• The outer region of the kidney containing:
• Bowman's capsules: Sites where filtration begins.
• Convoluted tubules: Proximal and distal tubules for reabsorption and secretion.
• Blood vessels: Deliver blood to the nephrons.

3. Medulla:

• The inner region of the kidney containing:
• Loops of Henle: Create a concentration gradient for water reabsorption.
• Collecting ducts: Transport urine towards the renal pelvis.
• Blood vessels: Network of capillaries aiding in exchange processes.

4. Renal Pelvis:

• A funnel-shaped cavity that collects urine from the collecting ducts and delivers it to the ureter.

Nephron Structure:

5. Bowman's Capsule:

• Cup-shaped structure surrounding the glomerulus where ultrafiltration occurs.

6. Proximal Convoluted Tubule (PCT):

• Reabsorbs glucose, amino acids, salts, and water into the blood.

7. Loop of Henle:

• Descending limb: Permeable to water, not salts.
• Ascending limb: Permeable to salts, not water.
• Creates a concentration gradient in the medulla.

8. Distal Convoluted Tubule (DCT):

• Adjusts the concentration of salts and controls pH through selective reabsorption.

9. Collecting Duct:

• Reabsorbs water under the influence of antidiuretic hormone (ADH).