Role of Organs in Digestion and Absorption

Mouth: Digestion begins in our mouth, where food is mixed with saliva, which lubricates it for easy swallowing and begins the breakdown of carbohydrates into simpler forms of sugar through an enzyme called amylase found in the saliva.
Oesophagus: This muscular tube transports food from the mouth to the stomach through muscular contractions known as peristalsis.
Stomach: Partial digestion of the proteins happens here due to the release of a strong acid (hydrochloric acid) and enzyme pepsin. It also churns food into a semisolid mixture called chyme and sends it to the small intestine.
Liver: Not directly involved in digestion, but secretes bile that is stored in the gallbladder and later released into the small intestine. Bile emulsifies large fat droplets into smaller ones, increasing the surface area available for enzymes to break down fats into glycerol and fatty acids.
Pancreas: This organ produces strong digestive enzymes (like proteases, lipases, and amylases) that break down proteins, fats, and carbohydrates respectively. It also secretes a substance that neutralises stomach acid to prevent damage to the intestinal walls.
Small intestine: Here, the digestion of nutrients is completed, and they are absorbed into the bloodstream. This organ has villi and microvilli, little finger-like projections that increase the surface area available for nutrient absorption.
Large intestine (Colon): Its main role is to reabsorb water and electrolytes from the remaining non-digested food to stop them from being lost in faeces; houses bacteria that break down undigested materials; finally, it forms and stores faeces.
Rectum and Anus: These are involved in the expulsion of faeces from the body, the final step of the digestive process.

Each one of these organs plays a well-orchestrated role, ensuring the breakdown of food into simpler nutrients that the body can absorb and use for various metabolic processes. Understanding this sequence can ensure a good grasp on the topic of digestion and helps to tackle related biological questions efficiently.