Allison Wetshtein Jessica Wetshtein Ch 41 Animal Nutrition

Overview Herbivores- eat mainly autotrophs (plants and algae) Nutrition- food being taken in, taken apart, and taken up Herbivores- eat mainly autotrophs (plants and algae) Carnivores- eat other animals Omnivores- eat other animals Animals must eat- balance, consumption, use, and storage

41.1 An Animal’s diet must supply chemical energy, organic molecules, and essential nutrients Energy from food powers cellular function Food supplies organic carbon and nitrogen for the construction of organic molecules Essential nutrients are the materials that an animal’s cells need but can’t synthesize Three nutritional needs: chemical energy for cell processes, organic building blocks for carbohydrates and macromolecules, and essential nutrients

41.1 cont. Essential amino acids- amino acids must be obtained from food in prefabricated form A diet low in amino acids causes and malnutrition called protein deficiency

Essential amino acids for humans Methionine Valine Threonine Phenylalanine Leucine Isoleucine Tryptophan Lysine legumes corn

41.1 cont. Animals synthesize most fatty acids they need Essential fatty acids- are certain unsaturated fatty acids that must be obtained from the diet

41.1 cont. Vitamins are organic molecules required in the diet in small amounts Vitamins are grouped into two categories: fat-soluble and water-soluble Minerals are simple inorganic nutrients, usually required in small amounts

41.1 cont. Undernourishment is the result of a diet that consistently supplies less chemical energy than the body requires Malnourishment is the long-term absence from the diet of one or more essential nutrients

Ingestion is the act of eating 41.2 The Main Stages of food processing are ingestion, digestion, absorption, and elimination Ingestion is the act of eating Digestion is the process of breaking food down into molecules small enough to absorb Absorption is uptake of nutrients by body cells Elimination is the passage of undigested material out of the digestive compartment

small molecules pieces of food chemical nutrient mechanical digestion molecules digestion enter body cells undigested material 1. Ingestion 2. digestion 3. absorption 4. elimination

41.2 cont. Suspension Feeders Many aquatic animals are suspension feeders, which sift small food particles from the water Humpback whale

41.2 cont. Substrate Feeders Substrate feeders are animals that live in or on their food source larva of a moth

41.2 cont. Fluid Feeders Fluid feeders suck nutrient-rich fluid from a living host mosquito

41.2 cont. Bulk Feeders Bulk feeders eat relatively large pieces of food python

41.2 cont. Food is processed in specialized compartments that reduce the risk of an animal digesting its own cells and tissue This is either intracellular or extracellular

41.2 cont. In intracellular digestion, food particles are engulfed by phagocytosis and pinocytosis and digested within food vacuoles

41.2 cont. Extracellular digestion is the breakdown of food in compartments that are continuous with the outside of an animal’s body It occurs in compartments that are continuous with the outside of the animal’s body Animals with simple body plans have a gastrovascular cavity that functions in digestion and distribution of nutrients

Concept 41.3: Organs specialized for sequential stages of food processing form the mammalian digestive system The mammalian digestive system consists of an alimentary canal and accessory glands that secrete digestive juices through ducts Food is pushed along the alimentary canal by peristalsis, alternating waves of contraction and relaxation in the smooth muscles lining the canal Sphincters, ringlike valves, regulate passage of material between compartments

41.3 cont. The oral cavity is the mouth and begins mechanical digestion Salivary glands initiate chemical digestion Amylase is the enzyme in saliva that hydrolyzes starch and glycogen The tongue forms the food into a ball shape called a bolus and pushes it into the back of the mouth

41.3 cont. The pharynx opens into the esophagus and stomach The esophagus is attached to the stomach

41.3 cont. The stomach stores food and secretes gastric juice, which converts a meal to acid chyme Gastric juice is made up of HCl and the enzyme pepsin Chief cells release pepsinogen, which is inactive until activated by HCl to form pepsin Mucus protects the stomach against self digestion

41.3 cont. Hydrolysis of macromolecules occurs in the small intestine The first 25 cm of 6 m is the duodenum where chyme mixes with stomach juices The pancreas aid digestion by producing proteases trypsin and chymotrypsin, which neutralizes acidic chyme

41.3 cont. The liver produces bile which helps digestion and absorption of lipids Bile is contained in the gallbladder The liver breaks down toxins and red blood cells that no longer function

41.3 cont. The epithelial lining of the duodenum produces several digestive enzymes The jejunum and ileum, the remaining regions of the small intestine, absorb nutrients and water

41.3 cont. The small intestine has a huge surface area, due to villi and microvilli Villi are finger like projections and microvilli are on the villi villus contains lacteal, a network of blood vessels and a small lymphatic vessel Capillaries and veins from the villi all meet in the hepatic portal vein and carry blood to the liver and heart

The structure of the small intestine Fig. 41-15 The structure of the small intestine Vein carrying blood to hepatic portal vein Microvilli (brush border) at apical (lumenal) surface Lumen Blood capillaries Epithelial cells Basal surface Muscle layers Large circular folds Epithelial cells Villi Lacteal Key Lymph vessel Nutrient absorption Villi Intestinal wall

41.3 cont. The alimentary canal ends with the large intestine, including the colon, cecum, and rectum. The cecum ferments ingested material The colon leads the rectum and anus and recovers water The rectum is the terminal portion of the large intestine, where feces are stored until eliminated

Mammals have adaptations associated with the animal’s diet Concept 41.4: Evolutionary adaptations of vertebrate digestive systems correlate with diet Mammals have adaptations associated with the animal’s diet Evolution of animals’ teeth is the reason they are successful carnivore herbivore omnivore

41.4 cont. Length of the vertebrate digestive system correlates with diet Herbivores and omnivores generally have longer alimentary canals than carnivores, because of the longer time needed to digest vegetation Carnivore herbivore

41.4 cont. Digestive adaptations involve mutualistic symbiosis, benefitting both species involved Ex. Koala have an enlarged cecum, where mutualistic bacteria ferment eucalyptus leaves

Concept 41.5: Homeostatic mechanisms contribute to an animal’s energy balance Overnourishment, eating more calories than necessary, leads to obesity and diabetes, colon and breast cancer, and cardiovascular disease Humans have homeostatic mechanisms that help regulate body weight In our evolutionary past, having fat meant surviving