Human Physiology: Class 11 CBSE Biology Study Notes
Human Physiology is a fascinating branch of biology that explores the intricate workings of the human body. It delves into how our organs, tissues, and cells function individually and collectively to maintain life. Understanding these processes is crucial for comprehending health, disease, and the remarkable adaptability of our bodies.
This comprehensive guide covers the major systems of human physiology as per the Class 11 CBSE syllabus.
1. Digestion and Absorption
Simple Explanation
Digestion is the process of breaking down complex food substances into simpler, absorbable forms. Absorption is the process by which these simpler forms pass from the digestive tract into the blood or lymph, to be transported to various cells of the body.
Key Points
- Alimentary Canal: A long tube extending from the mouth to the anus.
- Mouth: Mechanical digestion (chewing) and initial chemical digestion (salivary amylase for carbohydrates).
- Pharynx: Common passage for food and air.
- Oesophagus: Transports food to stomach via peristalsis.
- Stomach: Muscular bag; stores food, mixes it with gastric juice (HCl, pepsinogen, rennin); protein digestion begins.
- Small Intestine (Duodenum, Jejunum, Ileum): Primary site for complete digestion and absorption. Receives bile (fat emulsification) and pancreatic juice (enzymes for carbs, proteins, fats).
- Large Intestine (Caecum, Colon, Rectum): Absorbs water, electrolytes, and forms faeces.
- Anus: Egestion of faeces.
- Digestive Glands:
- Salivary Glands: Secrete saliva (salivary amylase, lysozyme).
- **Gastric Glands