1. Animal Nutrition
Chapter 41

2. The Need to Feed
Animals are
Herbivores
Carnivores
omnivores

3. Food and Nutrients
Food Any substance, either raw or processed which is meant for human consumption
Nutrients The components of food that the body can use for growth, repair and energy

4. Homeostatic Regulation
Glucose level rises, insulin is secreted
Insulintransport of glucoseliver & muscle store glucose lblood levels drop
Glucagon promotes the breakdown of glycogen blood glucose levels rise
Glucose level drops glucagon is made to oppose the effect of insulin

5. Appetite Regulating Hormones
PYY is an appetite suppressant
Ghrelin triggers hunger
Insulin suppresses appetite
Leptin suppresses appetite

6. Figure 41.2 A ravenous rodent
Obesity related to leptin.

7. Types of Nutrients
Carbohydrates
Proteins
Fats
Vitamins
Minerals
Water

8. Essential Nutrients Essential AA Essential fatty acids Vitamins
Minerals
Undernourishment vs. malnutrition

9. Essential Amino Acids Animals require 20 AA Can synthesize most
8 are essential, must obtain from food
How do vegetarians get all essential AA?

10. Essential Fatty Acids Need to obtain from food Unsaturated FA
Linoleic Acid

11. Essential Nutrients
What happens if an animal’s diet is missing an essential nutrient?
Deficiency Diseases
scurvy — vitamin C (collagen production)
rickets — vitamin D (calcium absorption)
blindness — vitamin A (retinol production)
anemia — vitamin B12 (coenzyme function)
kwashiorkor — protein

12. Vitamin Requirements of Humans: Water-Soluble Vitamins

13. Vitamin Requirements of Humans: Fat-Soluble Vitamins

14. Mineral Requirements

15. Intracellular Digestion in Paramecium
Digestion occurs in specialized compartments
Intracellular digestion occurs in protists and sponges

16. Gastrovascular Cavities and Extracellular Digestion
Gastrovascular cavities do both digestion and distribution
Ex. Cnidarians, platyhelminthes (flat worms)
Two-way digestion

17. One Way Digestive Tracts

18. Stages of Food Processing
Ingestion: eating or drinking
Digestion : Breaking food into smaller molecules
Mechanical
Chemical (Enzymes)
Absorption: nutrient molecules enter blood, the circulatory system transports it through out the body
Elimination: undigested material passes out of the body

19. The Digestive System
Functions like a series of tube like organs which pass through the body from the mouth to the anus Alimentary Canal
Alimentary Canal can be about 30’ long
Accessory organs Pancreas, Liver, Gallbladder secrete enzymes that are released into the food tube

21. Digestion in the Mouth

22. It all begins in the mouth . . .
Teeth, tongue
Salivary glands
Mucus
Amylase
Only carbohydrates are digested here

23. Swallowing and Peristalisis
Glottis and Epiglottis

24. From mouth to stomach: the swallowing reflex and esophageal peristalsis (Layer 2)

25. From mouth to stomach: the swallowing reflex and esophageal peristalsis (Layer 1)

26. Peristalsis
Rhythmic muscular contractions propel a bolus of food

27. The human digestive system

29. Digestion in the Stomach
Muscular organ
Acts as a reservoir where food is prepared for digestion in the SI
Produces Gastric Juices

30. Stomach Functions Food Storage Mechanical Digestion Chemical Digestion
Secretions:
Mucus
EnzymePepsinogen
HCL
CHYME semi-fluid food mixture leaves.

31. Protection from Self-Digestion
Protective lining
Main enzyme -Pepsin is inactive Pepsinogen when secreted

32. Digestion in the Stomach
Pepsinogen Comes in contact with HCl Pepsin
Pepsin converts proteins into peptones
Acidity of Gastric juices kills some bacteria that enters with food
Gastric Juices  stimulated by psychological and chemical means
Peristaltic process of moving chyme into the SI takes place for 6hrs

33. Small Intestine

34. Digestion in the Small Intestine
Main stage of Digestion
As chyme enters the SI secretes juices that are alkaline and neutralizes the acidity
SI maltase,lactase,sucrase breaks disaccharides
Liver secretes bile emulsifies fats
Dipeptidases  dipeptides into AAs
Pancreas
Trypsin & Chymotrypsin break down proteins
Amylase converts starch into maltose
Lipase breaks fats
Process is complete in about 4 hrs

35. Pancreas Secretes Hormones Sodium bicarbonate Digestive enzymes Lipase
Trypsinogen
Amylase

36. Liver Secretes Blood clotting enzymes Stores glycogen Bile
Stored in gall bladder
Emulsifies fat

37. Large Intestine = Colon
Anatomy:
Functions
a. Reclaim water
b. Synthesis of vitamins by E. coli
Feces
Rectum
Anus
Diarrhea
Constipation

38. Can you name the parts and tell what they do?

39. Food as Fuel
Carbohydrates, fats and proteins are all used to generate ATP
Fats9 Calories/gm, Proteins and Carbs 4Calories/gm
1 Calorie (kilocalorie)= 1000 calories
Basic Calorie need 2200 for female teens, 2500 males

40. Helicobacter pylori Bacteria-stomach feedback interactions
Coevolution of parasite & host
Free of H. pylori
Colonized by H. pylori
Bacteria-stomach feedback interactions
H. pylori bacteria colonize stomach
bacterial infection
causes damaging inflammation
increases stomach acidity
high rate of ulcer & stomach cancer
control with antibiotics
inflammation of stomach
inflammation of esophagus
H. pylori
cell damaging proteins
(VacA)
inflammatory proteins
(CagA)
Gastric ulcers, lesions in the stomach lining, are caused by the acid-tolerant bacterium Heliobacter pylori.
Ulcers are often treated with antibiotics.
cytokines
helper T cells
neutrophil cells
white blood cells

42. Accessory Organs LIVER A. Secretions B. Functions
1. Digestive function
2. Glycogenesis
3. Gluconeogenesis
4. Glycogenolysis
5. Hematopoiesis in embryo
6. Detoxification
7. Damaged red blood cell removal
bile contains pigment by-products of RBC
bile pigments eliminated from body with feces
brown feces = rusty iron from hemoglobin!

43. Pancreas a. Anatomy b. Functions c. Digestive Enzyme 1. trypsinogen
Acinar cells
Islets cells:Alpha, Beta
b. Functions
c. Digestive Enzyme
1. trypsinogen
2. chymotrypsinogen
3. carboxypeptidase
4. aminopeptidase
5. pancreatic amylase
6. pancreatic lipase
These accessory organs secrete their enzymes and a basic fluid into the duodenum of the small intestine

44. Figure The duodenum

45. Figure 41.18 Activation of protein-digesting enzymes in the small intestine

46. Small Intestine
a. Anatomy
1. size
2. villi
3. lacteals
4. glands
b. Functions
c. Secretions
1. mucus
2. maltase
3. sucrase
4. lactase
5. peptidase
6. enterokinase

47. Figure 41.19 The structure of the small intestine

48. Absorption in the Small Intestine villi microvilli
chylomicrons fats, cholesterol, wrapped in protein
leave cells by exocytosis
lacteals
lymphatic system
hepatic portal vein

51. MOUTH
What enzymes are made in the pancreas?
STOMACH
SMALL INTESTINE

53. Hormonal Control Enterogastrone Gastrin
Cholecystokinin secreted in response to the presence of amino acids or fatty acids, causes the gallbladder to contract and release bile into the small intestine and triggers the release of pancreatic enzymes
Secretin chyme(acidic pH)enters the duodenum, signals the pancreas to release bicarbonate to neutralize the chyme

54. Flora of Large Intestines
Living in the large intestine is a rich flora of mostly harmless bacteria
Escherichia coli
a favorite research organism
bacteria produce vitamins
vitamin K; biotin, folic acid & other B vitamins
generate gases
by-product of bacterial metabolism
methane, hydrogen sulfide

55. Large Intestines (colon)
Reclaiming water
used as solvent for various digestive juices
~7L of fluid secreted into digestive tract daily
> 90% of water reabsorbed
diarrhea = insufficient water absorbed
constipation = too much water absorbed

56. Large Intestine Wall
Numerous Goblet Cells

57. Figure 41.x1 Large intestine

58. Rectum Terminal portion of colon Feces contain masses of bacteria
undigested materials, mainly cellulose
roughage or fiber
salts
appendix

60. Structural Adaptations reflecting diet have made mammals very successful
1. Dentition

61. Structural Adaptations
2. Length of Digestive System

62. Structural Adaptations 3. # of Stomachs

63. Digesting Cellulose
How well you digest cellulose governs life strategy of herbivores
COW
Can digest cellulose well; not need to eat supplemental sugars
GORILLA
Can’t digest cellulose well; must supplement with sugar sources, like fruit

65. Figure 5.8 The arrangement of cellulose in plant cell walls

66. Figure 41.x2 Termite and Trichonympha
Protozoans and Bacteria have enzymes to digest cellulose