DIGESTIVE SYSTEM
The digestive system is responsible for breaking down food into nutrients that the body can
use for energy, growth, and repair. It also eliminates waste products. This
system involves several organs working together to process food, absorb
nutrients, and expel undigested waste.
Main Functions of the Digestive System:
1. Ingestion: The intake of food and liquids.
2. Mechanical Digestion: The physical breakdown of food into smaller
pieces (e.g., chewing, churning in the stomach).
3. Chemical Digestion: The breakdown of food into simpler molecules
through enzymatic action (e.g., enzymes in saliva, stomach acids, and
pancreatic enzymes).
4. **Absorption**: The process where nutrients from the digested food
pass into the bloodstream through the walls of the small intestine.
5. **Defecation**: The elimination of undigested food and waste products
from the body.
Main Organs of the Digestive System:
1. **Mouth**:
The digestive process starts here. Food is ingested, and mechanical digestion
occurs through chewing, while chemical digestion begins with enzymes in
saliva, like **amylase**, which begins breaking down carbohydrates.
, 2. **Esophagus**:
After swallowing, food passes through the esophagus, a muscular tube that
connects the mouth to the stomach. Peristalsis (wave-like muscle contractions)
moves the food down into the stomach.
3. **Stomach**:
The stomach continues the process of digestion. It has strong muscular walls
that churn food, mixing it with digestive juices, including **hydrochloric acid**
(HCl) and digestive enzymes, like **pepsin**, which begins protein
breakdown. The stomach also stores food and gradually releases it into the
small intestine.
4. **Small Intestine**:
This is the primary site for digestion and nutrient absorption. It has three
parts:
- **Duodenum**: Where most chemical digestion occurs with the help of
bile (from the liver) and pancreatic enzymes.
- **Jejunum**: The middle section where the majority of nutrient absorption
takes place.
- **Ileum**: The final section, where any remaining nutrients are absorbed.
Tiny finger-like structures called **villi** in the lining of the small intestine
increase surface area for absorption.
5. **Liver**:
The liver produces **bile**, a substance that helps break down fats into
smaller droplets for easier digestion in the small intestine. The liver also
detoxifies harmful substances and stores some nutrients.
The digestive system is responsible for breaking down food into nutrients that the body can
use for energy, growth, and repair. It also eliminates waste products. This
system involves several organs working together to process food, absorb
nutrients, and expel undigested waste.
Main Functions of the Digestive System:
1. Ingestion: The intake of food and liquids.
2. Mechanical Digestion: The physical breakdown of food into smaller
pieces (e.g., chewing, churning in the stomach).
3. Chemical Digestion: The breakdown of food into simpler molecules
through enzymatic action (e.g., enzymes in saliva, stomach acids, and
pancreatic enzymes).
4. **Absorption**: The process where nutrients from the digested food
pass into the bloodstream through the walls of the small intestine.
5. **Defecation**: The elimination of undigested food and waste products
from the body.
Main Organs of the Digestive System:
1. **Mouth**:
The digestive process starts here. Food is ingested, and mechanical digestion
occurs through chewing, while chemical digestion begins with enzymes in
saliva, like **amylase**, which begins breaking down carbohydrates.
, 2. **Esophagus**:
After swallowing, food passes through the esophagus, a muscular tube that
connects the mouth to the stomach. Peristalsis (wave-like muscle contractions)
moves the food down into the stomach.
3. **Stomach**:
The stomach continues the process of digestion. It has strong muscular walls
that churn food, mixing it with digestive juices, including **hydrochloric acid**
(HCl) and digestive enzymes, like **pepsin**, which begins protein
breakdown. The stomach also stores food and gradually releases it into the
small intestine.
4. **Small Intestine**:
This is the primary site for digestion and nutrient absorption. It has three
parts:
- **Duodenum**: Where most chemical digestion occurs with the help of
bile (from the liver) and pancreatic enzymes.
- **Jejunum**: The middle section where the majority of nutrient absorption
takes place.
- **Ileum**: The final section, where any remaining nutrients are absorbed.
Tiny finger-like structures called **villi** in the lining of the small intestine
increase surface area for absorption.
5. **Liver**:
The liver produces **bile**, a substance that helps break down fats into
smaller droplets for easier digestion in the small intestine. The liver also
detoxifies harmful substances and stores some nutrients.
