The Digestive Journey: How We Break Down Food

Our bodies require various building blocks for cells and energy production. These come from food, but they need to be transformed into smaller, absorbable molecules for our cells to utilize. This is where digestion comes in!

 

The Digestive System:

 

·         Alimentary Canal:

            A long tube stretching from mouth to anus, responsible for food breakdown and absorption.

o    Oral Cavity:

            Selection, grinding, and lubrication of food with saliva (contains enzyme amylase for starch digestion).

o    Pharynx and Oesophagus:

            Swallowing and movement of food using peristalsis (muscle contractions).

o    Stomach:

      Stores, mixes, and partially digests food with gastric juices (contains hydrochloric             acid and pepsin for protein digestion).

o    Small Intestine:

            Completes digestion and absorption:

§  Duodenum:

            Receives bile (fat breakdown), pancreatic juice (enzymes for protein, carbohydrate, and fat digestion), and intestinal juice (enzymes for final digestion).

§  Jejunum:

            Further digests proteins, carbohydrates, and lipids.

§  Ileum:

            Absorbs digested food molecules (sugars, amino acids) into blood and lymph (fats).

o    Large Intestine:

            Absorbs water, forms feces (undigested material), and eliminates waste through defecation.

 

Key Points:

 

·         Digestion breaks down complex food molecules into simpler ones for absorption.

·         Saliva starts digestion in the mouth (starch digestion).

·         Stomach muscles churn and mix food with gastric juices for protein breakdown.

·         Small intestine completes digestion with enzymes from pancreas and intestine, and absorbs nutrients.

·         Large intestine removes water from remaining food material and forms feces for elimination.

 

 

Following a Bite of Food:

 

Imagine a bite of bread (roti) with mutton. Let's see its journey:

 

1.     Oral Cavity:

            You taste and chew the food. Saliva moistens and begins starch breakdown.

2.     Swallowing:

            You swallow, and the food bolus travels to the stomach via the esophagus.

3.     Stomach:

            Gastric juices break down some protein in the mutton.

4.     Small Intestine:

o   Pancreatic enzymes and intestinal juices complete digestion of carbohydrates, proteins, and fats.

o   Digested sugars and amino acids are absorbed into the bloodstream through villi in the   small intestine.

    •  Fatty acids and glycerol are absorbed into the lymphatic system.

5.     Large Intestine:

            Water is absorbed, and remaining undigested material forms feces.

6.     Defecation:

            Feces are stored in the rectum and eliminated through the anus.

By understanding digestion, we appreciate how our bodies transform food into the essential building blocks for life!