Biology
Form III
BIO-F3-02
✓ Verified TIE Syllabus
Excretion in the Human Body
Physiology of waste elimination: human excretory organs (kidneys, lungs, skin, liver), mammalian urinary system gross anatomy, nephron ultrafiltration, selective reabsorption, and renal failure treatments.
📱
Study Offline with Faulu Plus App
Download full notes, flashcards, and AI tutor coaching on your device.
🎯 Syllabus Competencies & Learning Objectives
Key Competencies
- Main: 1.0 Demonstrate mastery of the concepts, principles and processes of Biology
- Specific: 1.1 Describe the physiological, anatomical and ecological processes of living organisms
Specific Learning Objectives
- Define excretion and differentiate it from egestion.
- Identify excretory organs and their metabolic waste products.
- Describe the macroscopic and microscopic structure of the kidney and nephron.
- Explain the mechanisms of urine formation: ultrafiltration and selective reabsorption.
- Describe kidney disorders (kidney stones, nephritis, renal failure) and dialysis.
📖 Comprehensive Study Notes Summary
### Excretion and Renal Physiology
Excretion is the removal of metabolic waste products, toxic substances, and substances in excess of requirements from an organism's body.
#### Urine Formation in the Nephron
1. **Ultrafiltration (Bowman's Capsule)**: High hydrostatic pressure in the glomerulus forces water, glucose, amino acids, urea, and mineral salts into the capsule, forming glomerular filtrate. Blood cells and large plasma proteins are retained.
2. **Selective Reabsorption (Proximal Convoluted Tubule)**: All glucose, all amino acids, and 85% of water/salts are actively reabsorbed into surrounding peritubular capillaries.
3. **Loop of Henle**: Establishes hypertonic medullary gradient for water conservation.
4. **Distal Convoluted Tubule & Collecting Duct**: Variable water and salt reabsorption controlled by ADH and aldosterone.
Excretion is the removal of metabolic waste products, toxic substances, and substances in excess of requirements from an organism's body.
#### Urine Formation in the Nephron
1. **Ultrafiltration (Bowman's Capsule)**: High hydrostatic pressure in the glomerulus forces water, glucose, amino acids, urea, and mineral salts into the capsule, forming glomerular filtrate. Blood cells and large plasma proteins are retained.
2. **Selective Reabsorption (Proximal Convoluted Tubule)**: All glucose, all amino acids, and 85% of water/salts are actively reabsorbed into surrounding peritubular capillaries.
3. **Loop of Henle**: Establishes hypertonic medullary gradient for water conservation.
4. **Distal Convoluted Tubule & Collecting Duct**: Variable water and salt reabsorption controlled by ADH and aldosterone.