the physical breakdown or digestion of food into smaller pieces by chewing, grinding and churning
Answer (1)
Mechanical Digestion: Key ProcessesChewing (Mastication)Location: MouthAction: Teeth tear, crush, and grind food into smaller pieces.Role of Saliva: Moistens food to form a bolus (soft mass) for easier swallowing.Churning (Stomach)Location: StomachAction: Smooth muscles in the stomach wall contract to mix food with gastric juices, creating chyme (a semi-liquid paste).Grinding (Small Intestine)Location: Small intestineAction: Peristalsis (wave-like muscle contractions) further breaks down food and mixes it with digestive enzymes.Why It MattersIncreases the surface area of food, making chemical digestion (by enzymes) more efficient.Prepares food for nutrient absorption in the intestines.Contrast with Chemical DigestionMechanical: Physical change (e.g., chewing an apple into pulp).Chemical: Enzymes break bonds in molecules (e.g., amylase turning starch into sugars).Example: Biting into bread (mechanical) vs. enzymes converting bread’s starch into glucose (chemical).
