One ATP Sandwich With extra phosphate Comin up Chapter Processing Food and Nutrition Chapter 21 Processing Food and Nutrition Objectives: 1. Understand the concepts of 2. Identify the anatomical parts 3. Describe the function of the noted parts 4. Describe the changes in processing food through the animal kingdom with a focus on vertebrates Jargon Elimination: Getting rid of digestive waste (called egestion in lower critters) Excretion: Getting rid of metabolic waste (function of kidneys and lungs) Digestion: 1. Break apart food into component molecules Degrade macromolecules into simpler compounds 2. Rearrange these molecules 3. Use now or later What Is The Diversity Of Digestive Systems In Non- Human Animals Intracellular in a sponge (a) Tube sponges carrying food particles enters the pores collar cell Water, uneaten food, and wastes are expelled through the large opening at one end of the sponge Food particles are filtered from the water by the collar Waste products are expelled by exocytosis The food vacuole merges with a lysosome (b) A simple sponge Food enters the collar cell by phagocytosis, forming a food vacuole (c) food vacuole Collar cell lysosome with digestive enz ymes Fig. 21-6
Extrace llu lar d ige stio n Dige stio n in a sac Animals? Annelids, mollusks, arthropods, and vertebrates are examples of animals with tube shaped gut. Lots of functions prey Soil with food particles is ingested intestine Indigestible remnants are expelled (a) Hydra with prey anus Tentacles with stinging cells capture the prey andcarry it into the Gland cells secrete digestive into the digestive sac and begin extracelular prey pharynx Nutritive cels engulf food particles and complete within food vacuoles (b) Food processing in Hydra digestive sac Fig. 21-7 esophagus crop Food is ground up in the gizzard gizzard in the intestine Fig. 21-8 Evolution of Digestion Complete Gut runs from to anus - food moves in one direction Digestion occurs outside the cells: Extracellular - Food absorbed by epithelial cells in gut Functions: 1. Movement 2. Secretion 3. Digestion 4. Absorption Complete Gut Digestion Generic Digestive Parts 1. Structures that take in food 2. Holding tank (some have crop) 3. Pulverizer (gizzards in birds and reptiles) 4. Place to expose food to 5. Place to absorb nutrients 6. Refuse area (where elimination stuff is stored)
Vertebrate Digestive Tract Mouth - Mastication 1. Capture and crush food Teeth! Why chew? 2. Lubrication and Enzyme (Amylase) Saliva Bolus is formed in The Swallowing Thing 1. With tongue, move food to back of Pressure against pharynx closes epiglottis against larynx (lungs), sealing airway 2. Pharynx to esophagus (connects to stomach) 3. Peristaltic movement down esophagus Enters through Sphincter muscle Bolus enters stomach and mixes with digestive juices = chyme 3 layers of muscle mechanical Stomach used for: Storage and Very little absorption occurs in stomach Parietal cells secrete Hydrochloric acid Chief cells secrete Pepsinogen Hydrochloric Acid: - kills bacteria - converts Pepsinogen to enzyme Pepsin (breaks apart proteins) Protection from Acid? Tightly packed epithelial cells Mucus for lubricates and protects Chyme remains in stomach ~ 2 hours - leaves stomach through pyloric sphincter LET S DIGRESS FOR A MOMENT!! Puking and throat burn!!!!!!!!!!!! Peptic Ulcer: Too much HCl, or too little mucus or Bacterium Helicobacter pylori
Accessory digestive organs Pancreatic Juice Contains water, bicarbonate, and digestive Digestive include amylase for starch, trypsin for proteins, and lipase for fats, deoxyribonuclease??? Liver weighs 3 lbs. below diaphragm - Makes bile Gallbladder 18-73 On to the Small Intestine (5-6 meters long 18 Ft!) 3 regions: 1) Duodenum 10 inches 2) Jejunum - 8 feet 3) Illium 12 feet Most Digestion and absorption occurs here Bile from liver added (fats) Enzymes from pancreas added (fats, peptides, carbs) Small intestine has characteristics that enhance surface area! - Folding of lining, Villi and Microvilli The small intestine fold of intestinal lining villi lacteal microvilli capillaries intestinal gland arteriole lymph vessel venule (a) (b) (c) (d) Small intestine A fold of the A villus intestinal lining Cells of a villus Chyme remains in small intestine from 3 to 10 hours Nutrients move to liver (Fat to cardiovascular system!) Fig. 21-12
Summary of Carbohydrates: Mouth, Stomach, Small Intestine Proteins: Stomach, Small Intestine Lipids (fats): Small Intestine Nucleic Acids: Small intestine Last, but not Least,,, The Large Intestine Little nutritional absorption occurs here! Parts: Cecum, ascending colon, transverse colon, descending colon, sigmoid colon, rectum, anus Elimination of waste Absorption of water and sodium Production of vitamin K and some B vitamins (bacteria) 5-6 feet long Chyme can stay in Large Int for a few hours up to days. Herbivores have special adaptations? Why? Cellulose!! Teeth adaptations: Premolars and molars - High crowned - Broad flat occlusal surfaces Stomach adaptations: - bacteria micro-organisms Coprophagy Reingesting feces - Why? - Cecum (houses bacterial microorgs.) - dry and gelatenous pellets - increased vitamins B and K