The Alimentary tract

The alimentary tract of a human being

Prepared:

From group 105 Ulug’berdiyeva Laylo

A long muscular tube with many sections and areas. Begins with the oral cavity and ends with the anus.

• Oral cavity(Cavum oris)
• Pharynx
• Esophagus
• Stomach
• Small Intestine (intestinum tenue)
• Large Intestine (colon)
• Anus

• Swallowing is a coordinated activity of the tongue, soft palate, pharynx and esophagus.
• Phases
• Food is pushed into the pharynx by the tongue. (voluntary)
• Tongue blocks the mouth
• Soft palate closes off the nose
• Larynx (Adam’s Apple) rises so the Epiglottis (a flap of tissue) can close the opening of the trachea.

• A straight muscular tube that is about 25 cm long which connects the mouth with the stomach
• Food takes about 4 to 8 seconds as it passes through to the stomach.
• Its walls contain smooth muscles that contracts in wavy motion (Peristalsis).
• Peristalsis propels food and liquid slowly down the esophagus into the stomach.
• Cardiac Sphincter (ring-like valve) relaxes to allow food into the stomach.

• J-shaped muscular sac
• Has inner folds (rugae) that increases the surface area of the stomach.
• Churns and grinds together the bolus into smaller pieces.
• Food is mixed with gastric juices (hydrochloric acid and enzymes) secreted by the stomach walls.
• HCL helps break down food and kills bacteria that came along with the food.

• The stomach lies between the esophagus and the duodenum (the first part of the small intestine). It is in the left upper part of the abdominal cavity. The top of the stomach lies against the diaphragm. Lying behind the stomach is the pancreas. A large double fold of visceral peritoneum called the greater omentum hangs down from the greater curvature of the stomach.
• Two sphincters keep the contents of the stomach contained; the lower esophageal sphincter (found in the cardiac region), at the junction of the oesophagus and stomach, and the pyloric sphincter at the junction of the stomach with the duodenum.

• The lesser curvature of the stomach is supplied by the right gastric artery inferiorly, and the left gastric artery superiorly, which also supplies the cardiac region. The greater curvature is supplied by the right gastro-omental artery inferiorly and the left gastro-omental artery superiorly. The fundus of the stomach, and also the upper portion of the greater curvature, is supplied by the short gastric artery which arises from the splenic artery.

• Long (5-6m), coiled tube beneath the stomach.
• Has three parts:
• Duodenum – upper part; 20-30Cc ; connected to the stomach.

– where the digestive juices from the pancreas and the liver combine with chyme making it thin and watery.

• Jejunum – about 100-110cm
• Ileum – about 150-160cm

• The duodenum is a short structure (about 20–25 cm long) continuous with the stomach and shaped like a "C".[7] It surrounds the head of the pancreas. It receives gastric chyme from the stomach, together with digestive juices from the pancreas (digestive enzymes) and the gall bladder (bile). The digestive enzymes break down proteins and bile and emulsify fats into micelles. The duodenum contains Brunner's glands, which produce a mucus-rich alkaline secretion containing bicarbonate. These secretions, in combination with bicarbonate from the pancreas, neutralizes the stomach acids contained in gastric chyme.

• The jejunum is the midsection of the small intestine, connecting the duodenum to the ileum. It is about 2.5 m long, and contains the plicae circulares, and villi that increase its surface area. Products of digestion (sugars, amino acids, and fatty acids) are absorbed into the bloodstream here. The suspensory muscle of duodenum marks the division between the duodenum and the jejunum.

• The ileum: The final section of the small intestine. It is about 3 m long, and contains villi similar to the jejunum. It absorbs mainly vitamin B12 and bile acids, as well as any other remaining nutrients. The ileum joins to the cecum of the large intestine at the ileocecal junction.

• Mixing: Segmental contraction that occurs in small intestine
• Secretion: Lubricate, liquefy, digest
• Digestion: Mechanical and chemical
• Absorption: Movement from tract into circulation or lymph
• Elimination: Waste products removed from body

• DIGESTION
• ABSORBTION
• IMMUNOLOGICAL

• a.k.a. Colon
• larger diameter, but shorter (1-1,5м)
• Water is absorbed from the undigested food making the waste harder until it becomes solid.
• Waste stays for 10 – 12 hours.

• Waste is pushed into the expanded portion (rectum) of the large intestine.
• Solid waste stays in the rectum until it is excreted through the anus as feces.
• Appendix hangs on the right side of the large intestine.

• Produce or store enzymes that helps in digestion.
• Liver
• Largest gland of the body
• Stores vitamins A,D,E,K
• Stores sugar and glycogen
• Produces bile (watery, greenish substance)
• Secretes bile to the gall bladder via the hepatic duct and cystic duct.

• Gross anatomy traditionally divided the liver into two portions– a right and a left lobe, as viewed from the front (diaphragmatic) surface; but the underside (the visceral surface) shows it to be divided into four lobes and includes the caudat and quadrate lobes