Digestion in Humans

Key Notes :

Definition of Digestion:

Digestive system(पचन संस्था)-MPSC Biology science notes
  • Digestion is the process of breaking down food into simpler forms that the body can absorb and use for energy, growth, and repair.

Digestive System Components:

  • Mouth: The digestion process begins here. Teeth break down food into smaller pieces, and saliva (containing the enzyme amylase) starts digesting starch.
  • Esophagus: A muscular tube that transports food from the mouth to the stomach through peristalsis (wave-like muscle movements).
  • Stomach: Produces gastric juices (containing hydrochloric acid and pepsin) to digest proteins. The acidic environment kills harmful bacteria.
  • Small Intestine: The main site of digestion and absorption. Digestive enzymes from the pancreas and bile from the liver help break down food.
  • Large Intestine: Absorbs water and minerals. The undigested waste is prepared for elimination.
  • Rectum and Anus: Store and eliminate solid waste from the body.

Role of Digestive Juices:

  • Saliva: Begins carbohydrate digestion in the mouth.
  • Gastric Juice: Aids protein digestion in the stomach.
  • Bile: Produced by the liver and stored in the gallbladder; helps emulsify fats in the small intestine.
  • Pancreatic Juice: Contains enzymes that digest proteins, carbohydrates, and fats.
  • Intestinal Juice: Completes the digestion of food into absorbable molecules.

Enzymes in Digestion:

  • Amylase: Breaks down carbohydrates into simple sugars.
  • Pepsin: Digests proteins into smaller peptides.
  • Lipase: Breaks down fats into fatty acids and glycerol.

Absorption:

  • Nutrients are absorbed in the small intestine via finger-like projections called villi. These increase the surface area for maximum absorption.
  • Glucose, amino acids, and fatty acids enter the bloodstream or lymph for transport to cells.

Egestion:

  • The removal of undigested and unabsorbed food material as feces through the anus.

Importance of a Balanced Diet:

  • A balanced diet ensures all nutrients are available for proper digestion and absorption.

Common Digestive Disorders:

  • Indigestion: Discomfort due to improper digestion.
  • Acidity: Excess production of stomach acid.
  • Constipation: Difficulty in passing stools due to low fiber intake or dehydration.

Tips for Healthy Digestion:

  • Eat fiber-rich foods.
  • Drink plenty of water.
  • Avoid overeating and processed foods.
  • Maintain regular meal times.

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