E CONTENT :

DIGESTIVE SYSTEM

All living organism require food for energy and organic matters for growth . food is organic compound and usually of plant or animal origin . The major components of our food are carbohydrates , proteins and fats . The process of conversion of complex food substances to simple absorbable term is called digestion and is carried out by our digestive system by mechanical and biochemical methods . The organs of the gastrointestinal tract includes the mouth , pharynx , esophagus ,

stomach , small intestine , large intestine .

a)            Mouth :

The mouth is formed by cheeks , palates , lips and tongue .

Teeth :

Teeth cut , tear and pulnerize food to reduce solids to smaller particles for swallowing . majority of mammals have two sets of teeth . an adult human has 32 permanent teeth which is of 4 types namely incisors , canine , premolars , and molars .

 Tongue :

Movement of tongue are important in guiding food within the mouth during chewing and swallowing . further more the taste buds are located on the tongue .

B ) PHARYNX :

When food is first swallowed , it passes from mouth into the pharynx , a funnel shaped tube that extends from the internal nares to the esophagus posteriorly . It acts as a common passage way for both the digestive system and the respiratory system .

C ) ESOPHAGUS :

The esophagus connects the pharynx to the stomach . It is a muscular tube approximately 25 cm long . In the esophagus , the submucosa contains mucus secreting submucosal esophageal gland . both submucosal and mucosal gland secrete mucus for lubrication of esophageal epithelial linning . The esophagus plays an important role in the chemical digestion of food .

D ) DIAPHRAGM :

The diaphragm is an important part of the body digestive  system . The muscular diaphragm separates the thoracic cavity from the abdominal cavity where most of the digestive organs are located . This muscle helps in flexure for the easy passage of digesting material .

E ) STOMACH :

The stomach is a major organ of the digestive system . It is a j shaped organ joined to the esophagus at its upper end and to the duodenum at its lower end . gastric acid produced in the stomach plays an important role in digestion . It mainly composed of hydrochloric acid and sodium chloride . The stomach of a new born baby will only be able to expand to retain about 30ml .

F ) SPLEEN :

The spleen breaks down both red and white blood cells. A product of digestion is the pigment bilirubin which is sent to the liver and secreted in the bile .

G ) LIVER :

The liver is the second largest organ and is an accessory digestive gland which plays a role in the body metabolism . the liver can detoxify various metabolites , synthesis protein , and produce biochemical needed for digestion . The liver also can synthesis glucose .

H ) GALL BLADDER :

The gall bladder is a hollow part of the biliary tract that sits just beneath the liver , with the gallbladder body resting in a small depression . It is divided into fundu , body and neck .

I ) PANCREAS :

The pancreas is a major part of digestive organ which has both endocrine and exocrine gland . The endocrine gland secretes insulin when blood glucose is high . The endocrine part releases glucagon when blood sugar is low . The pancreas is also the main source of enzymes for digestion of fats and proteins .

J ) SMALL INTESTINE :

Food starts to arrive in the small intestine one hour after it is eaten , and after two hours the stomach has emptied . In the small intestine , the pH becomes crucial , it needs to be finely balanced in order to activate digestive enzymes . when the digested food particles are reduced enough in size and composition , they can be absorbed by intestinal wall and carried to the bloodstream . 

The last part of the small intestine is the ileum . This also contains villi and vitamin b12 , bile acids , and any residue nutrients are absorbed here .

K ) LARGE INTESTINE :

It takes about 12 to 50 hours until it is removed by defecation . The colon mainly serves as a site for the fragmentation of digestible matter by the gut flora . The remaining  semi solid waste is termed feces and is removed by the coordinated contractions of the intestinal walls , termed peristalsis , which propels the excreta forward to reach the rectum and exit via defecation from the anus .

The 6 major functions take place in the digestive system  they are ,

·       Ingestion

·       Secretion

·       Mixing and movement

·       Digestion

·       Absorption

·       Excretion

DIGESTIVE DISORDER :

Many diseases and health conditions such as ulcers , GERD , IBD  and celiac disease .