DIGESTIVE SYSTEM

The Digestive System The digestive system

secretes enzymes and hormones that function in ingestion, digestion, and absorption of nutrients as well as in the elimination of the indigestible materials

The Digestive System The digestive system

1.Mouth2.Oesophagus 3.Stomach 4.Small intestine 5.Large intestine 6.Rectum

7.Anus.

DIGESTIVE SYSTEM

Mouth

The tongue is a mass of skeletal muscle covered by a stratified squamous epithelium containing elevated specializations called papillae.

The taste bud can detect four basic taste sensation – salty, sweet, sour, bitter.

Three salivary glands produce saliva.- Parotid, sublingual and

submandibular glands. Saliva has a number of other

functions including- 1) Moistening the oral cavity2) Cleansing the mouth 3) Moistening the food4) Facilitating swallowing5) Permitting the appreciation of taste

STOMACH: The stomach lies in the left side of the abdomen. Stomach is like a sac containing tiny glands called gastric glands. Which secretes gastric juices. The stomach opens into small intestine.

Stomach

Figure 23.14a

StomachFunction: The stomach acidifies and converts the

bolus into a thick, viscous fluid known as chyme. It also produces digestive enzymes and hormones.

Gastric juice presnet in stomach contains water, HCL, mucus, pepsin, lipase, rennin and pepsinogen becomes pepsin, which catalyzes the partial hydrolysis of proteins.

Small Intestine Small intestine: It is approximately 7

meters long and has three regions: the duodenum, jejunum and ileum.

Function:It largely completes the digestion of

foodstuffs and absorbs the resulting metabolites.

As liquid moves in the small intestine it mixes with enzymes delivered from the liver and pancreas through small tubes.

Large intestine Large Intestine: It consists of cecum,

colon, rectum anal canal and appendix. It contains some digestive enzymes received from the small intestine.

It houses bacteria that produce vitamin B12 and vitamin K;

vitamin B12 is necessary for hemopoiesis and the vitamin K for coagulation.

Large Intestine produces abundant mucus, which lubricates its lining and facilitates the passage and elimination of feces.Function: Primarily in the absorption of electrolytes, fluids and gases. Dead bacteria and indigestible remnants of the ingested material are compacted into feces.

DIGESTIVE GLANDS: Liver and Pancreas are the two digestive glands , that secretes juices for the digestive of food.

LIVER: The liver is the largest gland in the body. It lies on the left side in the upper part of abdominal cavity. The liver secretes a juice known as a bile.

Pancreas : Pancreas lies below the stomach .It is Leaf shaped . Pancreas secretes the pancreatic juice.

Three important functions of Saliva are -

Cleansing the mouthMoistening the oral cavityFacilitating swallowing

Gastric juice contains -

HCL,WaterMucus, PepsinLipase, Renin

The small intestine has following three parts -

duodenumjejunumileum

The large intestine houses bacteria that produces -

vitamin B12

vitamin K

Functions of large intestine include -

absorption of electrolytes, fluids and gases•passage and elimination of feces