Parts of digestion system

Parts of Digestion System

 Parts of digestion system 

Digestive system divided into two ways:

The alimentary canal divided into three parts

1. Fore gut

• Buccal cavity or mouth
• Pharynx
• Esophagus

2.Mid gut

 
• Stomach
• Intestine
 Small intestine
 Large intestine (caecum and colon portion comes in mid gut)

3. Hind gut 

 
• Large intestine (only rectum)
• Anus 

Organ involve in digestion

1. Buccal cavity or mouth
2. Pharynx
3. Esophagus
4. Stomach
5. Gall bladder
6. Pancreas
7. Liver
8. Small intestine
9. Large intestine
10. Anus

Function of stomach

Stomach composed with various varieties of cells, each cells have specific functions.
 

mucosa cells and mucous neck cells 

They cells secrets mucus, which form protective barrier that prevents digestion of stomach membrane/wall. These cells have also absorption properties that absorb small amount of water, short chain fatty acids and few drugs enter blood circulation.

Parietal cells

Parietal cells are secretes hydrochloric acid, which kill microbes present in food and converts pepsinogen into pepsin. These cells are also secretes intrinsic factor, that is needed for absorption of vitamin B12. Vitamin B12 is necessary for formation of red blood cells.

Chief cells

Chief cells are secretes gastric lipase that break triglycerides into fatty acids and monoglycerides. Chief cells are secretes pepsinogen enzyme that in the presence of hydrochloric acid convert into pepsin. Pepsin breaks down protein into peptides.

G-cells

G-cells are secrets gastrin which stimulates parietal cells to secrete hydrochloric acid.

Functions of saliva

1. Saliva composed with 99.5 % water and 0.5 % solute.
2. Saliva contain bacteriolytic enzyme lysozyme and salivary amylase, these are a digestive enzyme which act on starch.
3. Saliva is a slightly acidic pH 6.35-6.85.
4. Saliva lubricates food, so it can be moved easily in the mouth and swallowed.
5. Saliva contains immunoglobuline A (Ig A) which prevent attachment of microbes.  
6. Saliva helps to remove waste particles from the body.
7. Saliva lubricates food and break easily.