bab 7 sistem penghadaman 1

PENGENALAN DAN FUNGSI PENGHADAMAN

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Digestive System

• Alimentary Canal: hollow tube extending from mouth to anus• Technically outside the body• Covered with mucous membrane

• Accessory digestive organs – teeth, tongue, gallbladder, salivary glands, liver, and pancreas

FUNCTIONS OF THE DIGESTIVE SYSTEM

FUNCTIONS OF THE DIGESTIVE SYSTEM

1. Take in food

2. Break down the food

3. Absorb digested molecules

4. Provide nutrients

5. Eliminate wastes

The Digestive System

Digestive Tract Histology

1. Mucosa2. Submucosa3. Muscularis4. Serosa (adventitia)

Goals of the Digestive System

1. Extract nutrients from food

2. Transform nutrients into useful forms

Ex- oreo= glucose

3. Absorb nutrients and distribute them where they are needed

Functions of the Digestive System

• Ingestion: intake of nutrients

• Digestion: breakdown of large particles into smaller ones

• Absorption: uptake of nutrient molecules

• Defecation: elimination of undigested residues

Actions of the Digestive System

1. Motility- Breaks up food

- Moves food through the GI tract (Peristalsis)

- Mixes with digestive enzymes

2. Secretion- Release of enzymes and hormones for chemical

digestion and regulation

3. Membrane Transport- Absorption of nutrients from the tissues by the

blood and lymph for transport

Stages of Digestion

• Mechanical: physical breakdown of food

• Chemical: digestive enzymes hydrolyze food particles to break larger molecules into smaller ones

• Some nutrients are absorbed with out digestion– Vitamins, minerals, cholesterol, water