The Digestive System

The Mouth

The Stomach

Small Intestines

Here the food is ingested

Saliva: A mixture of mucous and serous fluid

Functions:
Dissolving food for Taste and Digestion
Mucos: Mostions food, lubricates oral surfaces
CI- Ions activate the Amalyse

Saliva contains salivary amylase, which is important when it comes to breaking down Carbohydrates (like starches)

Mechanical Digestion: Teeth mash the food together into a ball. Making the food easier to swallow.

Chemical Digestion: Amylase begins to break down starches and carbohydrates

Produced by the Salivary Glands. There are three pairs.
Composition of Saliva differ per each pair.

  1. Partoid Glands: Watery Saliva, Amalyse
  2. Sub-mandibular Glands: Thicker Mucose, Amalyse
  3. Sublingual Glands: Mostly Muscos, little Amalyse

Aids in Mastication (Chewing)

FUNCTION

Food breaks down into smaller fragments - Chyme

Peristalsis Occurs

Pylorus lets out Chyme into the small intestines

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Esophagus

Runs from the Pharynx to the stomach

The Pharynx and the esophagus are passageways for the food.

4 Layers within the wall

Peristalsis Occurs: involuntary constriction and relaxation of the muscles of the intestine. Pushing the contents of the canal forward. (MOVEMENT)

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There is a sharp transition from non Keritonizied stratified squamous to simple columnar epithelium when it meets the stomach

ANATOMY

The stomach is seperated into 3 parts:

The Fundus: Top portion of the stomach. Where the stomach meets the esophagus

The Body: Middle portion of the stomach

The Antrum of the stomach: Bottom portion of the stomach, where the stomach connects/meets the duodenum

Mucosa

Goblet cells produce alkaline mucus

Mucus surface layers trap a bicarbonate fluid beneath it

Gastric Pits

Mucus Neck Cells: Secrete mucus

Parietal Cells: Secrete HCL and intrinsic factor

Chief Cells: Produce pepsinogen and is activated by HCL in the stomach

Rugae: Folds of the mucosa

Storage Tank: Volume of 50ml to 4L

Liver

Pancreas

Controls blood glucose levels of the body: Insulin and glucagon

Produces digestive enzymes to break down food secreted into the duodenum

Produces and Excretes Bile- Emulsifies fat to aid enzymatic breakdown

LARGEST Internal organ and gland in the body

Pancreatic Juice: Contains water, salts, sodium bicarbonate, and enzymes that can digest foods of all types.

Secretion stimulates the secretion of bicarbonate. Without this we would burn holes through out intestines.

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Metabolizes fats, protiens and carbohydrates

Detoxification and purification of the blood

Storage of glycogen, vitamins, and minerals

Segmentation: Mixing of chyme and juices

Peristalsis- Movement

Absorbs mineral essential nutrients

ANATOMY

1st section: Duodenum- bile duct empties secretions into the small intestine

2nd Section: Jejunum

3rd Section: Ileum

Process

Ingestion: Voluntary movement of the food into the mouth

Absorption: End products of digestion are adsorbed into blood of lymph

Defecation: Elimination of undigestible substances as feces

Digestion

Mechanical

Chemical

Churning of food in the stomach

Segmentation/Mixing inside of the small intestine

Mastication/Chewing: Grinding and mixing of food in the mouth by teeth and tongue

Carbohydrates: Broken down into simple sugars by Amylase

Proteins: Broken down to simple sugars

Enyzmes break down food molecules into small units

Fats: Broken down into fatty acids and glyceol

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