Chapter 41: Animal Nutrition Jonah Lewis AP Biology Block C

I. Homeostasis and The Energy Budget Glucose Regulation o Glycogen: A polymer made of many glucose units that acts as a reserve of energy for the body. When in need body will burn glycogen to produce ATP.

Caloric Imbalance o Undernourishment: Chronically deficient in calories o Overnourishment: Excessive food intake, often leading to obesity  Obesity leads to many health problems, especially cardiovascular problems  Leptin: Hormone that regulates appetite in mammals  With weight loss, Leptin level increases, increasing appetite

II. Diet must supply carbon skeletons and essential nutrients Malnourished: Diet is missing one or more essential nutrients Essential Amino Acids: Amino acids that must be received from food, can not be made in body o Protein deficiency: Malnourishment caused by lack of essential amino acids

Essential Fatty Acids: Fatty acids body can not make for itself Vitamins: Organic molecules required in diet in relatively small amounts o Fat Soluble: Accumulate in fat  A,D,E, and K o Water Soluble: Are not stored in body for long periods of time  B complex: coenzymes  Vitamin C: Production of Connective Tissue

Minerals: Simple inorganic nutrients o Calcium and Phosphorus: Maintenance of bone o Magnesium, Iron, Zinc, Copper, Manganese, Selenium, Molybdenum: Part of structures of some enzymes. o Sodium, Chlorine, Potassium: Nerve functioning and osmotic balance between cells and in interstitial fluid

III. Food Processing in body Ingestion: The act of Eating Digestion: Process of breaking food down into molecules small enough for body to absorb o Enzymatic hydrolysis: Bonds broken with addition of water Absorption: Absorption of digested molecules Elimination: Undigested material passes out of system

Intracellular Digestion: Digestion within a cell, not widely used in animals Extracellular Digestion: Breakdown of food outside of cell, in a digestive sac o Gastrovascular cavity: a digestive sac that functions as both a place for digestion and to distribute nutrients o Complete Digestive Tract (Alimentary Canal): Digestive tube stretching between two openings

IV. Mammalian Digestive System Peristalsis: Contraction of smooth muscle that push food down alimentary tract Accessory glands o Salivary glands, pancreas, liver, and gallbladder Oral Cavity: Mechanical and some chemical digestion of food o Salivary Amlyase: enzyme in saliva that breaks down starch

Pharynx: Throat; leads to both the windpipe and esophagus o When swallowing the epiglottis covers the opening to the windpipe so food only goes to the esophagus o Esophagus: conducts food from pharynx to the stomach by muscle contractions (peristalsis) The Stomach: Stores food and performs preliminary digestion o Inside covered in mucous as to not self-digest o Churns food with Gastric juice  Pepsin: Enzyme that aids in digestion of proteins  Secreted by Chief Cells as inactive Pepsinogen  Parietal cells: Secrete hydrochloric acid which activates the pepsinogen in the stomach

The Small Intestine: Longest section of alimentary canal, where most digestion and absorption occurs o Duodenum: Beginning of small intestine where acid chyme from stomach mixes with more digestive juices o Bile: produced by liver and stored in gallbladder, aid in digestion o Villi and Microvilli: Projections into small intestine that greatly expands surface area to allow for absorption of nutrients. o Hepatic Portal Vessel: Blood vessel that leads directly to liver from Small Intestine

Large Intestine (The Colon) o Cecum: Pouch where bacteria live to help break down cell walls o Recovers water from feces (waste of digestive tract) and sends it back to body o Rectum: Terminus of large intestine where feces are stored until elimated from body

V. Evolutionary Adaptations to Digestive System Dentition: Arrangement of teeth o Teeth show kind of food an animal eats, as different kind of teeth tear different kinds of food Longer alimentary canals are common for herbivores because cell walls are harder to digest