Digestive system

• Components:

  primary organs: mouth, pharynx, esophagus, stomach, small intestines (duodenum, jejnum, ielum), large intrestine (colon), rectum and anal canal.

  acessory organs: salivary glands, liver, gall bladder, pancreas
• Functions:

  regulation of satiety and hunger

  mechanical digestion (mastication)

  swallowing and chemical digestion of food

  absorption of necessary nutrients

  elimination of unecessary matter and waste
• MOUTH

  Contains structures that start digestion.

  teeth: chopping the food.

  salivary glands: secrete saliva that contain enzymes that start chemical digestion of sugar and fats.

  tongue: detects taste, pushes bolus towards the pharynx
• Teeth

  Hard, conical structures attached to the sockets of the mandible and maxilla. They’re used in mastication and speech assistance.

  Children have 20 deciduous teeth.

  Adults have 32 teeth.
• Tongue

  Main organ of sense and taste, speech and swallowing food.
• Tongue: The root is the posterior part, where it is connected to the hyoid bone by the hyoglossus and genioglossus muscles and by the glossioid membrane; to the epiglottis, by three folds of the mucosa; to the soft palate, by the palatoglossal arches, and the pharynx, by the superior pharyngeal constrictor muscles and the mucosa.
• Stomach

  secretion of gastric acid that digests proteins and converts bolus to chyme.

  Parts

  cardia: where content of the esophagus empties into stomach.

  fundus: upper curved part

  body: central region

  pylorus: empties the chyme into the duodenum
• Organs

  Pharynx: conducts the food to the esophagus

  Esophagus: muscular tube that conducts the bolus to the stomach.

  -upper sphincter: opens with swallowing, allows the bolus to enter the esophagus.

  -lower sphincter: controls the emptying of the esophagus content to the stomach.

  It measures 25 centimeters in lenght.
• Parts

  cardia: where content of the esophagus empties into stomach.

  fundus: upper curved part

  body: central region

  pylorus: empties the chyme into the duodenum
• Spleen: breaks down spent erythrocytes.

  -production of bilirubin

  -bilirubin sent to the liver
• Liver: protein synthesis and energy storage.

  measures 6.5cm in diameter and 1.5 meters in length.
• Pancreas: secretes insulin when sugar levels are high, secretes glucagon when sugar levels are low.

  -Secretes pancreatic juice into the duodenum where it digests the chyme.

  -length: from 12.5 to 15 cm and its weight in women is 14.95 and in men 16.08.
• The duodenum mixes chyme with bile, secretes bicarbonates to rise pH in order to activate pancreatic enzymes which digest the chyme.
• The jejunum absorbs small nutrients that have been previously digested in the duodenum.
• The ileum absorbs vitamin B12, bile salts and all necessary matter that were not absorbed in the jejunum.
• The cecum is a pouch that marks the division between the small and large intestines, connecting the ileum with the ascending colon.
• Gallbladder (vesícula): empties bile into the duodenum. (7-10 cm long)
• The small intestine removed after death is about 7 meters long, and can vary between 5 and 8 meters, making it the same length as the small and large intestine together.
• large intestine: ascending colon, transverse colon, descending colon, sigmoid colon, rectum.