Animal Nutrition

nutrition Food taken in, taken apart and taken up Herbivores – plants/algae Carnivores – eat other animals Omnivores – consume animals and plants/algae Most animals are opportunistic – they will eat anything outside their diets when normal foods are not available.

Adequate diet Must satisfy 3 nutritional needs Chemical energy for chemical processes Organic building blocks for macromolecules Essential nutrients – preassembled organic molecules and minerals Essential fatty acids Essential amino acids Vitamins minerals Malnutrition – lacking 1 or more of the essential nutrients

Food processing – 3 steps 1. ingestion – act of eating or feeding 2. digestion – food broken down into molecules small enough for the body to absorb. 3. absorption – take up of small molecules such as amino acids and simple sugars Elimination – undigested material passes out of the digestive system

Digestion Digestive enzymes (amylase) begin digestion in mouth. Intracellular digestion – food vacuoles, paramecium Extracellular digestion – Gastrovascular cavity – hydra Complete digestive tract – alimentary canal, mouth and anus

Figure 33.8 Tongue Salivary glands Liver Gall- bladder Pancreas Small intestine Large intestine Rectum Anus Oral cavity Pharynx Esophagus Sphincter Stomach Liver Pancreas Gallbladder Duodenum of small intestine Stomach Small intestine Large intestine Rectum Anus Salivary glands Esophagus Mouth

Accessory glands of digestive system Mouth – salivary glands (accessory) Pancreas – endocrine gland Liver – filters blood, produces bile Gall bladder – stores bile, releases to S. Intestine Peristalsis – waves of contraction/relaxation to move food throughout alimentary canal. Sphincters – muscular rings that regulate passage to organs.

Oral cavity, pharynx and esophagus Oral cavity – mouth, digestion begins Tongue – helps shapes digested food into a ball – bolus Pharynx – splits into 2 passages Trachea – respiratory Esophagus – leads to stomach

stomach Stores food, begins digestion Secretes components of a digestive fluid – gastric acid HCL – makes pH around 2, denatures proteins Pepsin – protein-digesting enzyme Gastric acid does not affect cells lining stomach because of mucus released by cells Gastric ulcers – damaged areas of stomach lining

stomach Digestion occurs by churning of food (peristalsis) about every 20 seconds. Chyme – acidic nutrient rich broth made from food Stomach sphincters closed during digestion Acid reflex – chyme backflows into esophagus “heartburn”

Digestion in Small Intestine Most digestion of macromolecules from food, higher pH than stomach, trypsin enzymes Longest part of alimentary canal, 20 feet, 6 meters Duodenum, first 25 cm of small intestine, chyme mixes with digestive juices from pancreas, liver and gall bladder. Bile – product of liver, contains bile salts

Absorption in the small intestines Most absorption occurs across folded surface Villi, microvilli Surface area is roughly the size of a tennis court! Increase rate of absorption

Absorption of large intestines Includes the: Colon – ascending, transverse, descending, recovers water Cecum – pouch that ferments ingested material Appendix – finger like extension of the human cecum, contains bacteria to break down material, accessory Rectum – terminal portion, store feces until eliminated. Has two sphincters to regulate defecation Irritation of lining of colon – diarrhea

Dental/mutualistic adaptations Assortment of teach reflect the diet of the animal. Mutualistic bacteria and protists live in some digestive organs of certain animals to help with digestion. Koala – to break down eukalyptus Ruminant digestion – 4 chambered stomach Rabbits/rodents – bacteria in L.I Termites – protists to help break down cellulose

Regulation of digestion Nervous system involved by triggering of substances to be released (saliva, gastric juices) Endocrine system – controls digestion with release of hormones released by stomach and duodenum. Energy storage -