HUMAN Digestive system REVISION ON UNIT 1 HUMAN 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 Glands They 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

It tastes food and mixes it with saliva. Tongue: It tastes food and mixes it with saliva.

Common cavity leads to the esophagus and trachea. 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 cavity It has two main parts: Duodenum 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 pancreas Ileum: 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: Chew the food well Don’t eat much food containing fats such as fatty food. Don’t eat food containing additives. Don’t purchase food from streets to avoid infectious diseases. Practice sports .