1
Animal Nutrition-B2
I. Nutritional requirements
A. Heterotrophs
1. Animals
2. Fungi-parasitic plants
3. Needs
a.
b. material for biosynthesis
c. nutrients not made by the body
B. Homeostatic mechanisms
1. Fuel budget
a. high for ATP
b. Endotherms-maintenance of body temperature
c. Gets energy from cell respiration (oxidation)
~Carbs first
~
~Proteins last
2. Glucose regulation (regulated by hormones)
a. 1st used to make ATP thenb.
c. storage as fat
d. stored as glycogen
~in liver and muscles
3. Caloric imbalance (caloric deficiency)
a. undernourishment
~
~balanced diet needed!
b. overnourishment
~body becomes very efficient incarbohydrate digestion
~hoards fat
c. obesity Fig. 41.2 rodents
~body limits weight gain/loss
~
~beneficial to organisms that need long term supply of
calories
C. Essential nutrient needs & C skeletons
1.
2. Needs for biosynthesis (C skeletons)
3. Essential nutrients
a. lacking=malnourished
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b. Amino Acids
~20 AA to synthesize proteins
~
~must obtain in your diet
c. Fatty acids
~can synthesize most
d. vitamins
organic
~lack of can cause serious problems
~
~fat soluble
e. Minerals
inorganic
II. Food types & feeding mechanisms
A. Opportunistic feeders
1.
2. carnivores
3. omnivores
4. may consume food outside normal diet
B. Diverse feeding adaptations
1. Suspension feeders
a.
b. filter feeders
2. Substrate feeders
a. live in or on food source
b. ex. maggots
3. Fluid feeders
a.
b. leaches, mosquito ex.
4. Bulk feeders
a. eats large pieces of food
b. adaptations
~tentacles
~
~fangs
~jaws & teeth
III. Overview of food processing
A. Four stages
1.
a. taking in food
b. food complex + “packaged” macromolecules
2.
a. breaking food down so it can be absorbed
3
~
~used to make tissues
b. mechanical digestion
c. chemical digestion
3. Absorption—
4. Elimination—undigested material passes out of the body
B. Digestion occurs in special compartments
1. Intracellular digestion INSIDE CELL
a. food vacuoles + lysosomes
b.
c. phagocytosis/pinocytosis
d. ex. protists/sponges (Porifera)
2. Extracellular digestion OUTSIDE OF CELL
a. Extracellular cavity
b. allows for larger prey
c. gastrovascular cavity
d. single opening (digestive tract)
~simple organisms
~dig/circ/exc
e. two body openings (mouth/anus)
~ complete digestive tracts (alimentary canal)
~food moves in one direction
~able to take in food 24/7 (storage/grinding organs)
IV. The Mammalian Digestive System
A. Principles of food processing
1. peristalsis2. Spincters-controls movement of food through the Al. Canal
3. Accessory organs
a. salivary glands
b.
c. liver
d. gall bladder
~~~~~~~~~1st part of Alimentary Canal~~~~~
B. The Oral Cavity (Buccal)
1. mechanical digestion
~mucus released to protect
2. chemical digestion begins ~Carb. Digestion by Salivary Amylase
3.
C. Pharynx (throat) p. 861 fig. 41.14
1. Glottis (opening to lung)
2. Epiglottis (flap skin to prevent food from going into lungs
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D. The Esophagus (food tube)
1. food moves by peristaltic contractions through esophagus to
stomach
2. Top of Esophagus-voluntary
Bottom of Esophagus-involuntary
~~~~~~~~2nd part of Alimentary Canal~~~~~~
E. The Stomach (2-6 hours)
1. stretches to hold 2L
2.
3. mechanically breaks food down
4. Protein digestion begins/CHOcontinues
a. pH 1.5/2.0
b.
c. pepsin breaks protein bonds
d. Pepsin secreted in inactive form
e. Pepsin + HCl=protein digestion
f. Ex. positive feedback
5. Cardiac sphincter (btwn esop/st)
6.
7. Churning-3 layers muscle tissue laying at different angles
8. layers of mucus for protection
9.
I. The small intestine (bowel-colon)
1. 25 ft. (6 m)
2. where most digestion and ALL absorption of nutrients takes place
3. Duodenum (10 inches/25 cm)
a. Acid chyme & digestive juices from pancreas, liver, gall
bladder & intestinal glands mix
b.
c. liver releases bile (stored in gall bladder)
d. bile salts help to absorb fat
e. liver filters out dead RBC’s bile pigment—color to feces
*********CHEMICAL DIGESTION*********
~~Carbohydrate digestion continues
Amylase and Disaccharidases
~~Protein digestion continues
Peptidases
~~Nucleic Acid digestion begins
Nucleases
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~~Fat digestion begins
Lipases
Emulsification needed to begin
4. Jejenum (22 ft)
a. absorbs nutrients & water
b.
c. absorption from lacteals (lymph) and epithelial tissue to
capillary
d. Energy Usage-passive and active transport
5. Ileum
a.
b. sphincter opens to Large Intestine
~~~~~~~~3rd part of the Alimentary canal~~~
J. Large Intestine (bowel-colon)
1. 5-6 ft/ 12-24 hours to go through the intestines
2. Reclaiming water its main function
3.
a. 1st area after the sphincter
b. appendix location
4. diahhrea/constipation
5. Vitamin production
a.
b. some Vit. B
c. folic acid/biotin
6. Anatomy of Large Intestine
a. cecum/Ascending colon
b.
c. Descending colon
d. Sigmoid (s-shaped)
e. Rectum
f. anus/anal opening
7. Rectum (storage of feces)
a.
b. 1 involuntary/1 voluntary
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V. Evolutionary adaptations for digestion
A. Structure & Diet p. 867
1. Types of teeth
2. Length of Alimentary canal & diet
~carnivore shorter than herbivore
B. Symbiotic microorganisms
1. Microbes that can absorb cellulose
a. ex. herbivore canals (ruminates)
b. Ex. termites
c. crops (organ) in birds
d.