الرحيم الرحمن الله بسمMinistry of High

EducationAlmajmaa University College of Medicine

Digestion

objectivesA- list the general function of various parts of GI system .

B- list gastro-intestinal hormones , identify their source and list one function of each .

C- identify the components of enteric nervous system ( ENS ) and describe its function in control of GIT activity .

D- Define digestion and absorption and then list the major sites for digestion and absorption of CHO , proteins and lipids .

The main Objectives

list the general function of various parts of GI system .

list gastro-intestinal hormones , identify their source and list one function of each .

Digestive SystemYour digestive system is turn the food you eat into energy your body needs to surviveThe organ of digestive system are :

MouthThroatEsophagusSmall IntestineLarge intestine Pancreas LiverGallbladder

mouth : The mouth is the beginning of the

digestive tract . Chewing and breaks the food

into pieces that are more easily digested.

Throat : Also called the pharynx the throat is the next site for

food you've eaten. From here, food travels to the esophagus .

Esophagus : The esophagus is a

muscular tube extending from the pharynx to the stomach .

By means of a series of contractions, called peristalsis the esophagus delivers food to the stomach .

Stomach : • The stomach is a sac-like

organ with strong muscular walls

• In addition to holding the food, it's also a mixer and grinder .

• The stomach secretes acid and powerful enzymes that continue the process of breaking down the food.

• When the food leave the stomach it is look like liquid or paste .

Small intestine : Made up of three parts :

duodenum, jejunum, and ileum .

the small intestine is a long tube loosely coiled in the abdomen The small intestine continues the process of breaking down food by using enzymes released by the pancreas and bile from the liver.

Bile is a compound that aids in the digestion of fat and eliminates waste products from the blood.

• Large intestine : The large intestine (colon) is the last part of the digestive system.

• Its function is to absorb water from the remaining indigestible food matter, and then to pass useless waste material from the body by Rectum then anus.

Pancreas : Among other functions, the pancreas secretes enzymes into the small intestine. These enzymes break down protein, fat, and carbohydrates from the food we eat .

Liver : has many functions, but two of its main functions within the digestive system are :

make and secrete bile cleanse and purify the blood coming

from the small intestine containing the nutrients just absorbed .

Gallbladder : The gallbladder is a pear-shaped reservoir that sits just under the liver and stores bile.

Bile is made in the liver then travels to the gallbladder through a channel called the cystic duct.

During a meal, the gallbladder contracts, sending bile to the small intestine.

second Objectives:

list gastro-intestinal hormones , identify their

source and list one function of each .

What is gastro-intestinal hormones ?

• The GI hormones are secreted by epithelial cells lining the lumen of the stomach and small intestine .

• GI hormones are secreted into blood . • they affect function of other parts of the

digestive tube , liver, pancreas, brain .

function source Hormones

the secretion of gastric acid is stimulated

secreted by the mucous lining of the

stomach

Gastrin

that stimulates the secretion of pancreatic

enzymes

in the small intestine Cholecystokinin

that stimulates the secretion of water and bicarbonate from the

pancreas

into the small intestine

Secretin

controlling smooth muscle contractions

in the stomach and small intestine

Motilin

Inhibits gastric secretion

in the small intestine Gastric inhibitory peptide

summary

The digestive system is one of the most important system in the body, the organ of the GI system digest the food which is the source of energy .

Food passes through several stages (Mouth - pharynx- esophagus – stomach – small intestine - large intestine ) to Absorption of nutrients With the help of enzymes .

Questions?

Resources • GUYTON AND HALL textbook of Medical

physiology . • Medicine books web site.

Thank you Don by : Mohammed Abdullah Hazazi 2nd year medical student

Supervisor : DR. Kamran Afzal Assistant Professor of Physiology