revision on unit 1 human digestive system. the living organism body consists of a set of systems....
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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 .