REVISION ON UNIT 1HUMAN Digestive system

The living organism body consists of a set of systems.

Digestive system:

It digests and absorbs food

Respiratory system:It carries the process of

breathing.

Circulatory system: It distributes the digested

food and oxygen all over the body cells.

Urinary system: It helps the body to get rid of

the harmful substances.

Nervous system: It lets us have the ability to

feel, hear, see, smell, and taste.

Reproductive system: It gives birth for new

individuals

HUMAN DIGESTIVE SYSTEM

WHAT IS IT ?

Digestive System breaks down food into simpler substances for absorption into the blood stream.

MOUTH

Digestion begins at the mouth, where food is taken in and broken down into smaller particles by chewing. Saliva in the mouth moistens the food.

The Teeth

The teeth chew and tear the food into small bits of pieces.

Salivary GlandsThey produce liquid like material called Saliva. Saliva has a digestive substance called enzymes.

Enzymes: digest starches and converts them into simpler substances known as sugars

Tongue:It tastes food and mixes

it with saliva.

Pharynx:

Common cavity leads to the esophagus and trachea.

OESOPHAGUS

The esophagus is the tube that carries food, liquids and saliva from your mouth to the stomach.

STOMACH

Stomach secretes gastric juice . Muscular sac works on mixing food.- Food changes into semi-liquid substance.- Incomplete digestion of protein by gastric juice The food then passes into the small intestine.

SMALL INTESTINE

Food is further digested in the small intestine with the help of enzymes from the pancreas and bile from the liver.

•Length about 7 meters. Coils inside the abdominal cavityIt has two main parts:

1. Duodenum

2. Ileum

Duodenum: is the first part of the small intestine where

a- Bile juice is secreted from the liver.

b- Pancreatic juice poured from the pancreasIleum: the digestion to different types of food is completed.

Remember:Bile juice: helps to digest fats where it changes fats into fatty emulsion

Absorption: takes place through the small intestine walls

LIVER

LARGE INTESTINE

Starts with the rectum and end in then anus. Rectum: water is absorbed from food remains. Anus: wastes are ejected out of the body.

Keeping the digestive system healthy:1. Chew the food well2. Don’t eat much food containing fats

such as fatty food.3. Don’t eat food containing additives.4. Don’t purchase food from streets to

avoid infectious diseases.5. Practice sports .