CHAPTER 41 ANIMAL NUTRITION

1. CHAPTER 41 ANIMAL NUTRITION LEPTIN = apetite suppressor (hormone produced by fat cells)

2. The four main stages of food processing are ingestion, digestion, absorption, and elimination

3. Why Eat? C6H12O6 + 6O2 -> 6CO2 + 6H2O + Energy (ATP + heat) ATP (Cell Respiration) • FUEL • BIOSYNTHESIS • ESSENTIAL NUTRIENTS Organic Macromolecules

4. Everything you eat gets DIGESTED into glucose, amino acids, and glycerol + fatty acids • These 3 digestion products enter cell respiration (glycolysis and Kreb’s cycle) • Products of cell respiration – CO2, NH3, H2O, ATP • These end products can be used for cellular work (movement), generating heat, and BIOSYNTHESIS • Excess gets converted to GLYCOGEN or FAT! CO2, other simple compounds Why Eat? ATP • FUEL • BIOSYNTHESIS • ESSENTIAL NUTRIENTS Organic Macromolecules

5. Carbon Skeletons, and other simple products of cell respiration Why Eat? ATP • FUEL • BIOSYNTHESIS • ESSENTIAL NUTRIENTS BIOSYNTHESIS = ANABOLIC PATHWAY Biosynthesis = Making of New Proteins, Carbohydrates, Fats, Nucleic Acids needed by the body using the energy and raw material derived from food

6. How much energy do you get from food? • Carbohydrates – 4 kcal/gm • Proteins – 4 kcal/gm • Fats – 9 kcal/gm • Calorie = heat required to raise the temperature of water by 10c • Kcal = 1000cal • Cell Respiration = process that “burns” food • Carbs = quick energy release • Fats, proteins = slow to release energy

7. What happens to excess carbs? • Gets stored as glycogen in liver and muscle • Too much carb? -Gets converted into fat!!!! • Glycogen can be released quickly during exercise • Disadvantge – less energy (4 kcal/gm) • Fats – more energy (9kcal/gm), takes time to release

8. How is glucose regulated? • Insulin (produced by the Islets of Langerhans - in pancreas) = decreases blood sugar by ? • Glucagon (pancreas) = increases blood sugar by ?

9. Animals require 20 amino acids to make proteins. • Essential amino acids must be obtained from food in prefabricated form. (eight) Protein Deficiency - Kwashiorkar

10. Essential fatty acids. • Certain unsaturated fatty acids, including linoleic acids required by humans. • Deficiencies are rare. Mahatma Gandhi once said, "Where ever flaxseeds become a regular food item among the people, there will be better health".

11. Vitamins -organic molecules required in the diet in very small quantities (upto 100 mg)

14. Minerals are simple inorganic nutrients, usually required in small amounts - from less than 1 mg to about 2,500 mg per day.

16. Human Digestive System • Alimentary canal + accessory glands that secrete digestive juices into the canal through ducts. • Peristalsis: rhythmic waves- push food along. • Sphincters: muscular ringlike valves, regulate the passage of food • Accessory glands - salivary glands, the pancreas, the liver, and the gallbladder.

17. When does the lunch you had today complete its passage through your digestive system? • Mouth: Seconds • Esophagus: Seconds • Stomach: 2-6 hours • Small Intestine: 5-6 hrs.• Large Intestine: 12- 24 Hours TOTAL = 19 – 36 hrs!!

18. Fig. 41.13

19. The journey begins …… • Physical: chewing -Increases surface area of food • Saliva - Moistens + Kills bacteria + Buffer • Chemical digestion: Enzyme • Salivary Amylase – Acts on “AMYLOSE” - long straings of glucose found in starch/glycogen • (starch + glycogen) -> (smaller polysaccharides + maltose)

20. Pharynx (throat) - opens to esophagus and the trachea (windpipe). • Epiglottis - cartilaginous flap prevents food going into the windpipe

21. Epiglottitis

22. Fig. 41.14

24. The stomach • Muscular Organ – peristalisis -chyme - mixture of gastric juice+food • Gastric juice - glands • Parietal cells - HCl – pH 2!! -kills bacteria; converts pepsinogen -> pepsin (inactive)->(active) • Chief cells - Pepsin – action = proteins -> polypeptides + amino acids • Mucous cells - Mucous prevents eating away of stomach lining

25. Pyloric Sphincter-prevents back flow of food!

26. Small intestine is the major organ of digestion and absorption • 6 m long • First section – duodenum • LOTS OF ENZYMES FROM ACCESSORY GLANDS • Pancreas makes – 1)pancreatic amylase - acts on polysachcharides -> tri, di saccharides; 2)bicarbonate - changes pH to make it basic so enzymes can act on the food; 3)trypsin, chymotrypsin - act on polypeptides ->tri & dipeptides , 4)lipase - acts on fats -> fatty acid and glycerol, 5)nucleases act on DNA and RNA -> nucleotides • Liver makes bile; gall bladder – stores bile; bile emulsifies fats • Lining of intestine – other enzymes (intestinal juice); convert to monomers

28. . Fig. 41.18

29. Jejunum, ileum – sections of small intestine – absorption of nutrients into lymph/blood - see notes in powerpoint slide for details Active transport –glucose, amino acid, vitamins Passive transport - fructose

30. Hormones help regulate digestion • Hormones released by wall of the stomach and duodenum • Ensure that digestive secretions are present only when needed. • Stomach wall - hormone gastrin (stimulates gastric juice) • Duodenum – hormone Secritin (pancrease releases bicarbonate) • Duodenum – hormone Cholecystokinin (CCK)- gallbladder releases bile

31. Reclaiming water is a major function of the large intestine • Cecum- very mall in humans - appendix

34. Fig. 41.12

35. Structural adaptations of digestive systems are often associated with diet

36. (1) Fig. 41.22