Human digestive system | Human anatomy and physiology notes

Digestive system :

The digestive system is responsible for the breakdown of complex non absorable components like carbohydrate, proteins, fats in to simplest unit like glucose, amino acid, fatty acid respestivily.
Human digestive system , d pharmcy and b pharmacy notes

Digestive system consists of -

1. Mouth.                4. Small intestine
2. Pharyngitis.       5. Large intestine
3. Esophagus.         6. Rectum
4. Stomach.             7. Anus

1.  Mouth :

-  It is the first part of the digestive system. The ph: of mouth is 7
-  It is the entry point of the food.
-  It contain salivary gland that produce and secret saliva in to oral cavities.
-  Saliva moistened the food contains enzymes begins the digestion of starch in to smaller polysaccharide.

Anatomy of mouth :

Lips - It protect the anterior opening.
Cheeks - It form the lateral walls.
Hard palate - It form the anterior roof.
Soft palate - It form the posterior roof.
Oral cavity - The area contain by the teeth.
Vestibule - Space between the lips and teeth.

Function of mouth :

-  It helps in mechanical digestion.
-  It increase the surface area for faster chemical digestion.

2. Esophagus :

- It is a tube that connect the mouth to the stomach.
-  It runs through the oral cavity.

Location :

-  It lies begins the windpipe.
-  The trachea has an epiglotis which prevent food from entering the windpipe and moving the food to the esophagus.
-  Food travels down the esophagus  through a rhythmic contractions called peristalisis.

Function :

-  The lining of the esophagus secretes mucus that lubricate the food.
-  To support the movement of food.

3. Stomach :

-  It is located on the left side of the abdominal cavity.
-  Food enters at the cardioesopphageal sphincter. Protein digestion begins.
-  It is a j shaped muscular sac.
-  Inner folds that increased the surface area of the stomach .
-  External region are   -  Lesser curvature and greater curvature.

Function :

Stomach helps in the mechanical digestion.
- By churning the bolous and mixed with the gastric juices.  
-  Gastric juices are HCl, water and salts etc.

Small intestine :

It is responsible for the complete digestion of all macromolecules and absorption of their component.

Parts of small intestine :

Duodenum :

-  The first part is duodenum  and it is a u shaped organ.
-  It is approximately 30 cm in length.
-  This area complete most of the digestion.
-  The duodenum is lined by folds of tissue called villi.


-  The jejumum is approximately 3m long.
-  Although absorption occur here, It is responsible for pushing the waste material in to large intestine.

Jejunum :

-  The ilum is approximately 2.5 m long.
-  Some of the digestion completed here and it is responsible for absorption of nutrients.

Function :

-  90% of digestion and absorption of food occur here.
-  Other 10% occur in the stomach and large intestine.
-  The main function is absorption of nutrients and minerals from the food material.

Components of large intestine :

The large intestine composed of - 

1. Cecum:

First section of large intestine and it looks like a pouch. Its function is to passes the good in to colon.

2. Colon :

Major section of the large intestine and its function is water absorption, absorption of salts etc.

Rectum :

- It is the last section and it measures from 1 to 1.6 inches.
-  Leftover wastes are collected there and emptied through anus.

Post a Comment (0)
Previous Post Next Post