HUMAN DIGESTIVE

SYSTEM

What is digestive system?

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Digestive system is a group of organs and associated digestive glands that take part in ingestion of food , it’s crushing , digestion , absorption of digested materials and egestion of waste.

DigestionFlowing phases are Included in the process:

1. Ingestion

2. Movement

3. Mechanical and Chemical Digestion

4. Absorption

5. Elimination

Digestive System Organization Structures in digestive system:

• Mouth• Pharynx• Esophagus• Stomach• Small intestine• Large interstine.

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MouthO Teeth mechanically break

down food into small pieces. Tongue mixes food with saliva (contains amylase, which helps break down starch).

O Epiglottis is a flap-like structure at the back of the throat that closes over the trachea preventing food from entering it.

DigestionO TypesO Mechanical (physical)

O ChewO TearO GrindO MashO Mix

O ChemicalO Enzymatic reactions to improve digestion of

O CarbohydratesO ProteinsO Lipids

EsophagusO Approximately 10” longO Functions include:1. Secrete mucus

2. Moves food from the throat to the stomach using muscle movement called peristalsis

O If acid from the stomach gets in here that’s heartburn.

StomachO J-shaped muscular bag that stores the food

you eat, breaks it down into tiny pieces.O Mixes food with digestive juices that contain

enzymes to break down proteins and lipids.O Acid in the stomach kills bacteria.O Food found in the stomach is called chyme.

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LiverDirectly affects digestion by producing

bileO Bile helps digest fat• filters out toxins and waste including

drugs and alcohol

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Gall Bladder

O Stores bile from the liver, releases it into the small intestine.

O Fatty diets can cause gallstones

PancreasO Produces digestive enzymes to

digest fats, carbohydrates and proteins

O Regulates blood sugar by producing insulin

Small IntestineO Small intestines are roughly 7 meters longO Lining of intestine walls has finger-like

projections called villi, to increase surface area.

O The villi are covered in microvilli which further increases surface area for absorption.

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Small Intestine

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O Nutrients from the food pass into the bloodstream through the small intestine walls.

O Absorbs:O 80% ingested waterO VitaminsO MineralsO CarbohydratesO ProteinsO Lipids

• Secretes digestive enzymes

Large IntestineO About 5 feet longO Accepts what small intestines don’t

absorbO Rectum (short term storage which holds

feces before it is expelled).

Large IntestineO Functions

O Bacterial digestionO Ferment carbohydratesO Protein breakdown

– Absorbs more water– Concentrate wastes

Accessory Organs

O Not part of the path of food, but play a critical role.

O Include: Liver, gall bladder, and pancreas