Understanding Animal Nutrition and Digestion for Better Health

1. Chapters 41-47

2. Internal regulation • Interstitial fluid: internal fluid environment of vertebrates; exchanges nutrients and wastes • Homeostasis: “steady state” or internal balance • Negative feedback: change in a physiological variable that is being monitored triggers a response that counteracts the initial fluctuation; i.e., body temperature • Positive feedback: physiological control mechanism in which a change in some variable triggers mechanisms that amplify the change; i.e., uterine contractions at childbirth

4. Metabolism: sum of all energy-requiring biochemical reactions • Catabolic processes of cellular respiration • Calorie; kilocalorie/C • Endotherms: bodies warmed by metabolic heat • Ectotherms: bodies warmed by environment • Basal Metabolic Rate (BMR): minimal rate powering basic functions of life (endotherms) • Standard Metabolic Rate (SMR): minimal rate powering basic functions of life (ectotherms)

5. Chapter 41 • Animal Nutrition

6. Nutritional requirements • Essential nutrients: materials that must be obtained in preassembled form • Essential amino acids: the 8 amino acids that must be obtained in the diet • Essential fatty acids: unsaturated fatty acids • Vitamins: organic coenzymes • Minerals: inorganic cofactors

7. Food types/feeding mechanisms • Opportunistic • Herbivore: eat autotrophs • Carnivore: eat other animals • Omnivore: both • Feeding Adaptations • Suspension-feeders: sift food from water (baleen whale) • Substrate-feeders: live in or on their food (leaf miner) (earthworm: deposit-feeder) • Fluid-feeders: suck fluids from a host (mosquito) • Bulk-feeders: eat large pieces of food (most animals)

8. Overview of food processing Earthworm http://www.tvdsb.on.ca/westmin/science/snc2g1/wormdig.htm Bird http://people.eku.edu/ritchisong/birddigestion.html Grasshopper http://kentsimmons.uwinnipeg.ca/16cm05/16labman05/lb6pg17.htm • 1-Ingestion: act of eating • 2-Digestion: process of food break down • enzymatic hydrolysis • intracellular: breakdown within cells (sponges) • extracellular: breakdown outside cells (most animals) • alimentary canals (digestive tract) • 3- Absorption: cells take up small molecules • 4- Elimination: removal of undigested material

9. Mammalian digestion • Peristalsis: rhythmic waves of contraction by smooth muscle • Sphincters: ring-like valves that regulate passage of material • Accessory glands: salivary glands; pancreas; liver; gall bladder

10. Mammalian digestion http://highered.mcgraw-hill.com/sites/0072437316/student_view0/chapter43/animations.html# • Oral cavity • salivary amylase- carbs • •bolus • Pharynx • •epiglottis • Esophagus • Stomach: protein • •gastric juice •pepsin/pepsinogen (HCl) • •acid chyme • •pyloric sphincter • Small intestine •duodenum • Intestinal digestion: • a-carbohydrate • b-protein • c- nucleic acid • d-fat •bile http://www.whfoods.com/genpage.php?tname=faq&dbid=16#digestion

11. Bile http://www.zerobio.com/cck_flash.htm Mammalian digestion

12. Mammalian digestion • Villi / microvilli • Lacteal (lymphatic) • Chylomicrons (fats mixed with cholesterol) • Hepatic portal vessel: to liver

13. Hormonal Action: Gastrin food---> stomach wall ---> gastric juice Enterogastrones (duodenum) 1-Secretin acidic chyme---> pancreas to release bicarbonate 2-Cholecystokinin (CCK) amino/fatty acids---> pancreas to release enzymes and gall bladder to release bile Large intestine (colon) Cecum Appendix Feces Rectum/anus Mammalian digestion

14. Evolutionary adaptations • Dentition: an animal’s assortment of teeth • Digestive system length • Symbiosis • Ruminants

15. Chapter 42 • Circulation and Gas Exchange

16. Circulation system evolution, I • Gastrovascular cavity (cnidarians, flatworms) • Open circulatory •hemolymph (blood & interstitial fluid) •sinuses (spaces surrounding organs) • Closed circulatory: blood confined to vessels • Cardiovascular system: •heart (atria/ventricles) •blood vessels (arteries, arterioles, capillary beds, venules, veins) •blood (circulatory fluid)

17. http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookcircSYS.htmlhttp://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookcircSYS.html Circulation system evolution, II Earthworm http://yucky.discovery.com/noflash/worm/multi/heart.mov • Fish: 2-chambered heart; single circuit of blood flow • Amphibians: 3-chambered heart; 2 circuits of blood flow- pulmocutaneous (lungs and skin); systemic (some mixing) • Mammals: 4-chambered heart; double circulation; complete separation between oxygen-rich and oxygen poor blood

18. Double circulation Pulmonary/systemic http://www.wisc-online.com/objects/ViewObject.aspx?ID=AP12704

19. Heart anatomy http://www.wisc-online.com/objects/ViewObject.aspx?ID=AP12504 The mammalian heart Cardiac cycle http://msjensen.cehd.umn.edu/1135/Links/Animations/Flash/0028-swf_the_cardiac_cy.swf • Cardiac cycle: sequence of filling and pumping • Systole- contraction • Diastole- relaxation • Cardiac output: volume of blood per minute • Heart rate- number of beats per minute • Stroke volume- amount of blood pumped with each contraction • Pulse: rhythmic stretching of arteries by heart contraction Blood flow http://www.sumanasinc.com/webcontent/animations/content/human_heart.html

20. The heartbeat • Sinoatrial (SA) node (“pacemaker”): sets rate and timing of cardiac contraction by generating electrical signals • Atrioventricular (AV) node: relay point (0.1 second delay) spreading impulse to walls of ventricles • Electrocardiogram (ECG or EKG) Open heart surgery http://www.abc.net.au/science/lcs/swf/heart.swf

21. Blood vessel structural differences Capillary fluid exchange http://msjensen.cehd.umn.edu/1135/Links/Animations/Flash/0029-swf_fluid_exchange.swf Low pressure Away Toward heart Thicker: more pressure Gas exchange, osmosis, diffusion

22. The lymphatic system • Lymphatic system: system of vessels and lymph nodes, separate from the circulatory system, that returns fluid and protein to blood • Lymph: colorless fluid, derived from interstitial fluid • Lymph nodes: filter lymph and help attack viruses and bacteria • Body defense / immunity

23. Blood • Plasma: liquid matrix of blood in which cells are suspended (90% water) • Erythrocytes (RBCs): transport O2 via hemoglobin • Leukocytes (WBCs): defense and immunity • Platelets: clotting • Stem cells: pluripotent cells in the red marrow of bones • Blood clotting: fibrinogen (inactive)/ fibrin (active); hemophilia; thrombus (clot)

25. Cardiovascular disease • Cardiovascular disease (>50% of all deaths) • Heart attack- death of cardiac tissue due to coronary blockage • Stroke- death of nervous tissue in brain due to arterial blockage • Atherosclerosis: arterial plaques deposits • Arteriosclerosis: plaque hardening by calcium deposits • Hypertension: high blood pressure • Hypercholesterolemia: LDL, HDL

26. Gas exchange • CO2 <---> O2 • Aquatic: gills , ventilation, countercurrent exchange • Terrestrial: •tracheal systems •lungs

28. Larynx (upper part of respiratory tract) Vocal cords (sound production) Trachea (windpipe) Bronchi (tube to lungs) Bronchioles Alveoli (air sacs) Diaphragm (breathing muscle) Mammalian respiratory systems

31. Thoracic cavity pleura diaphragm intercostal muscles Role of pressure inspiration What happens with pressure and the volume of the chest cavity? Expiration What happens with pressure and the volume of the chest cavity? How do we breathe?

33. Why do we need to breathe? Gas exchange system Requirements of respiratory membranes: must be moist. Must be thin must be permeable to gases. All organisms must have a mechanism with which to transport gases. (circulatory system) Movement of gases happens by simple diffusion. Respiratory System

35. Breathing • Positive pressure breathing: pushes air into lungs (frog) • Negative pressure breathing: pulls air into lungs (mammals) • Inhalation: diaphragm contraction;Exhalation: diaphragm relaxation • Tidal volume: amount of air inhaled and exhaled with each breath (500ml) • Vital capacity: maximum tidal volume during forced breathing (4L) • Regulation: CO2 concentration in blood (medulla oblongata)

36. Where does it occur? What gases are exchanged? Simple diffusion is responsible. Erythrocytes RBCs Role of hemoglobin Structure of hemoglobin Oxyhemoglobin 4 oxygens at a time. Effects of CO Carbon dioxide is largely transported as a dissolved gas in the plasma although some is transported by hemoglobin Gas Exchange

37. Respiratory pigments: gas transport • Oxygen transport- • Hemocyanin: found in hemolymph of arthropods and mollusks (Cu) • Hemoglobin: vertebrates (Fe) • Carbon dioxide transport- • Blood plasma (7%) • Hemoglobin (23%) • Bicarbonate ions (70%)

39. http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter25/animation__gas_exchange_during_respiration.htmlhttp://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter25/animation__gas_exchange_during_respiration.html

40. Respiratory Center Medulla Oblongata Brainstem Peripheral Chemoreceptors aorta and carotid arteries increase in Carbon dioxide increases H+ ion concentration. Central chemoreceptors in the brain are sensitive to this. Increase CO2, Increase breathing rate. Hyperventilation Control of breathing

41. Gills Structure Why do fish suffocate on land? Countercurrent flow Insects - spiracles tracheae tracheoles Why can’t this work in us? Snail and Frogs Have lungs, but very little respiratory surface area. Cutaneous Breathing. Other mechanisms of breathing

47. Chapter 43 • The Body’s Defenses

48. Lines of Defense Nonspecific Defense Mechanisms……

49. Phagocytic and Natural Killer Cells • Neutrophils 60-70% WBCs; engulf and destroy microbes at infected tissue • Monocytes5% WBCs; develop into…. • Macrophagesenzymatically destroy microbes • Eosinophils 1.5% WBCs; destroy large parasitic invaders (blood flukes) • Natural killer (NK) cellsdestroy virus-infected body cells & abnormal cells

50. The Inflammatory Response • 1- Tissue injury; release of chemical signals~ • histamine (basophils/mast cells): causes Step 2... • prostaglandins: increases blood flow & vessel permeability • 2/3- Dilation and increased permeability of capillary~ • chemokines: secreted by blood vessel endothelial cells mediates phagocytotic migration of WBCs • 4- Phagocytosis of pathogens~ • fever & pyrogens: leukocyte-released molecules increase body temperature