Structures and Process of Digestion Class Notes PDF

Structures of the Human Digestive System Peristalsis  Digestion in Humans 1. Ingestion o Getting food inside the body through the mouth 2. Physical Breakdown o Reduces pieces of food into small chunks o Involves the mouth; biting and chewing by teeth, tongue and the pe...

Structures of the Human Digestive System Peristalsis  Digestion in Humans 1. Ingestion o Getting food inside the body through the mouth 2. Physical Breakdown o Reduces pieces of food into small chunks o Involves the mouth; biting and chewing by teeth, tongue and the peristaltic movements of the stomach 3. Chemical Breakdown o Food is broken down into subunits which can enter cells o Involves enzymes in mouth, stomach, and small intestine (from gall bladder and pancreas)  Digestion in Humans 4. Absorption o Small molecules (monomers) such as monosaccharides, amino acids, fatty acids and glycerol diffuse into the bloodstream through the walls of the small intestine 5. Egestion o Elimination of unusable food from the body o Involves rectum and anus  Structure Function in Relation to Digestion get food into body Mouth mechanical and chemical digestion (amylase) Salivary Glands release salivary amylase for chemical digestion manipulates food while chewing Tongue moves bolus to the back of the pharynx Esophagus performs peristalsis that moves food from mouth to stomach mechanical digestion (peristalsis) Stomach HCl (destroys microbes) and pepsinogen pepsin (proteins) Duodenum – mech and chem digestion, secretions from pancreas + liver Small Intestine Jejunum – most chem digestion and absorption Ileum – absorption absorption of water and vitamins Large Intestine assembly of some vitamins by bacteria Accessory Organs Liver Produce bile (1 L / day) Produces HCO3-1 to neutralize HCl from stomach Pancreas Produces lipases, protease Stores and concentrates bile Gall Bladder Bile released via common bile duct into duodenum  Section of the Features / Function Small Intestine enzymes are secreted from the pancreas bile enters from the gallbladder to break up Duodenum lipids physically many villi to increase surface area for absorption more villi are present Jejunum breaks down remaining carbs and proteins Ileum fewer and smaller villi Compound Produced In Active in Function salivary salivary mouth polysaccharides disaccharides amylase gland pepsin stomach stomach polypeptides dipeptides HCl stomach stomach pepsinogen pepsin bile liver duodenum fat into fat droplets  Compound Produced In Active in Function sodium pancreas duodenum neutralizes acidic chime from stomach bicarbonate pancreatic pancreas duodenum polysaccharides disaccharides amylase lipase pancreas duodenum fat droplets glycerol + fatty acids trypsin pancreas duodenum dipeptides amino acids chymotrypsin pancreas duodenum dipeptides amino acids Compound Produced In Active in Function maltase jejunum jejunum maltose glucose + glucose lactase jejunum jejunum lactose glucose + galactose sucrase jejunum jejunum sucrose glucose + fructose peptidase jejunum jejunum dipeptide amino acids Absorption in Small Intestine