Animal Nutrition Ch 41 Lecture Objectives 1 Importance

Animal Nutrition Ch. 41 Lecture Objectives 1. Importance of Food 2. Stages of Food Processing 3. Mammalian Alimentary Canal

An Animals Diet Must Provide 1. Chemical energy for cellular processes 2. Organic building blocks for macromolecules 3. Essential nutrients (amino acids, fatty acids, vitamins, and minerals) - lack of can cause deformities, disease, and death © 2014 Pearson Education, Inc.

Figure 41. 3 © 2014 Pearson Education, Inc.

Four Stages of Food Processing © 2014 Pearson Education, Inc.

Figure 41. 5 1 INGESTION Mechanical digestion 2 DIGESTION 3 ABSORPTION 4 ELIMINATION © 2014 Pearson Education, Inc. Chemical digestion (enzymatic hydrolysis) Nutrient molecules enter body cells Undigested material

Suspension Feeders and Filter Feeders Baleen Types of Feeders Substrate Feeders Fluid Feeders Caterpillar

Digestive Compartments 1. Most animals process food in specialized compartments 2. These compartments reduce the risk of an animal digesting its own cells and tissues - Intracellular Digestion: food particles are engulfed by phagocytosis food vacuoles, containing food, fuse with lysosomes containing hydrolytic enzymes (i. e. sponges) - Extracellular Digestion: breakdown of food particles outside of cells in compartments that are continuous with © 2014 Pearson Education, Inc.

Figure 41. 7 Mouth Tentacles 1 Digestive enzymes Food are released from a gland cell. 2 Enzymes break food down into small particles. 3 Food particles are engulfed and digested in food vacuoles. Epidermis © 2014 Pearson Education, Inc. Gastrodermis

Alimentary Canals © 2014 Pearson Education, Inc.

Figure 41. 8 Esophagus Crop Gizzard Intestine Pharynx Anus Mouth (a) Earthworm Foregut Midgut Hindgut Rectum Anus Esophagus Mouth (b) Grasshopper Crop Stomach Gastric cecae Gizzard Intestine Mouth Esophagus Crop (c) Bird © 2014 Pearson Education, Inc. Anus

Figure 41. 9 Tongue Oral cavity Salivary glands Pharynx Mouth Esophagus Liver Gallbladder Pancreas Sphincter Rectum Anus © 2014 Pearson Education, Inc. Gallbladder Liver Sphincter Stomach Small intestine Large intestine Esophagus Pancreas Anus Duodenum of small intestine Salivary glands Stomach Small intestine Large intestine Rectum

The Oral Cavity, Pharynx, and Esophagus 1. Oral cavity - Masticate Food - Salivary glands - mucus, antibacterials, buffers, & amylase - Chew food into the shape of a bolus © 2014 Pearson Education, Inc.

2. Esophagus & Peristalsis Bolus of food Tongue Epiglottis up Pharynx Esophageal sphincter contracted Glottis Larynx Trachea Esophagus Epiglottis down Glottis up and closed Esophageal sphincter relaxed To To lungs stomach (a) Trachea open (b) Esophagus open Figure 41. 10 © 2014 Pearson Education, Inc.

Figure 41. 11 Stomach Gastric pit on the interior surface of stomach 3. Stomach & Gastric Juices (Mucus, HCl, Pepsinogen & Pepsin) Epithelium 3 Pepsinogen Gastric gland Mucous cell Chief cell Parietal cell © 2014 Pearson Education, Inc. Chief cell Pepsin (active HCl enzyme) 2 1 Cl− H+ Parietal cell

4. Small Intestine: Duodenum 1 Gallbladder Liver Stimulation Inhibition Food Stomach Gastric Gastrin juices

Figure 41. 12 ORAL CAVITY, PHARYNX, ESOPHAGUS CARBOHYDRATE DIGESTION Polysaccharides Disaccharides (starch, glycogen) (sucrose, lactose) Salivary amylase Smaller Maltose polysaccharides PROTEIN DIGESTION Proteins STOMACH Pepsin Small polypeptides SMALL INTESTINE (enzymes from pancreas) NUCLEIC ACID DIGESTION DNA, RNA Pancreatic amylases Disaccharides Pancreatic trypsin and chymotrypsin FAT DIGESTION Fat (triglycerides) Pancreatic nucleases Nucleotides Pancreatic lipase Smaller polypeptides Pancreatic carboxypeptidase Glycerol, fatty acids, monoglycerides Small peptides SMALL INTESTINE (enzymes from intestinal epithelium) Nucleotidases Disaccharidases Monosaccharides © 2014 Pearson Education, Inc. Dipeptidases, carboxypeptidase, and aminopeptidase Amino acids Nucleosides Nucleosidases and phosphatases Nitrogenous bases, sugars, phosphates

5. Small Intestine: villi, microvilli & absorption Vein carrying blood to liver Blood capillaries Epithelial cells Muscle layers Intestinal wall Nutrient absorption Villi Large circular folds Villi Microvilli (brush border) at apical (lumenal) surface Epithelial cells Lumen (toward capillary) Lacteal Lymph vessel Basal surface Figure 41. 13 © 2014 Pearson Education, Inc.

6. Large Intestine Ascending portion of colon Small intestine Appendix Cecum © 2014 Pearson

Stomach and Intestinal Adaptations 1. Carnivores large, expandable stomachs 2. Herbivores & Omnivores longer alimentary canals than carnivores, reflecting the longer time needed to digest vegetation © 2014 Pearson Education, Inc.