Transcript Ch. 41animal nutrition rauch

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Chapter 41 ~
Animal
Nutrition
Nutritional Requirements
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Undernourishment:
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Overnourishment
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Malnourishment: essential
caloric deficiency
(obesity): excessive food
intake
 Leptin-appetite
supressing hormone
nutrient deficiency
Leptin deficient rat on left
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Essential nutrients:
materials that must be
obtained in preassembled
form
Essential amino acids: the
8 amino acids that must be
obtained in the diet
Complete & incomplete
proteins, limiting amino acids.
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Essential fatty acids:
unsaturated fatty acids;
linoleic; and alphalinolenic; Ω-3; Ω-6
phospholipids in cell
membranes—esp. nervous
tissue
Special Adaptations
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Adelei penguinsAntartica
Store extra protein.
Amino acids from
catabolism used to
replace feathers
following molting.
(amino acids not stored)
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Vitamins:
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many are organic coenzymes (B-vits)
a) water soluble-excreted
b) fat soluble-stored in adipose
tissue—can be toxic in excess
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A,D,E,K
A) Vision-Retinol; skin
D) bone development—rickets—bowed legs
E) antioxidant
K) blood clotting
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Minerals: inorganic cofactors
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Calcium: bones; muscle contraction;
nerve impulses
Iodine: goiter; naturally occuring in
marine water
Iron: oxygen transport (hemoglobin)
Food types/feeding mechanisms
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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); hummingbirds
Bulk-feeders: eat large pieces of
food (most animals)
Overview of food processing-4 stages
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1-Ingestion: act of eating
2-Digestion: process of food break
down
enzymatic hydrolysis
A) intracellular: breakdown within
cells (sponges); or within
membrane (paramecium)
B) extracellular: breakdown outside
cells (most animals)
alimentary canals (digestive tract)
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3- Absorption: cells take up small
molecules
4- Elimination: removal of
undigested material
Extracellular
digestion
Hydra
 2 tissue layers
 Inner layer
Forms digestive
Cavity
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Incomplete digestive
System
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(only 1 opening)
Fig. 41.11
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Mammalian digestion I
(complete- 2 openings)
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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
Mammalian digestion: 1. Ingestion
& initial digestion
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Oral cavity
Mechanical and chemical digestion
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Teeth-reduce size\increase
surface area
•salivary amylase •bolus
Pharynx-juncture
•epiglottis-cartilage flap, closes
off trachea when swallowing
Esophagus—food tube
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Bolus passes through Cardiac Sphincterenters stomach
(occasional backflow—heartburn)
Preliminary digestion, stores food
Mechanical (churning) and chemical
digestion
gastric juice secreted: Contains HCl &
pepsin
pepsinogen activated to pepsin via HCl-begins protein digestion
Positive feedback-increasingly more
pepsin activation
Fig.
41.14
•acid
chyme
•pyloric sphincter--------Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Stomach
Small Intestine: Digestion &
Absorption: Digestion of carbohydrates,
proteins, nucleic acids, fats
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Acid Chyme passes through Pyloric Sphincter into Small
intestine (duodenum)
bile: secreted into S.I.
 Produced by liver
 Stored in Gall Bladder
 Bile salts-emulsifiers ( no enzymes)—break up & coat fat
Some proteases secreted by intestine
Pancreas: secretes bicarbonate & enzymes
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Amylases (carbs); lipases (fats); nucleases
some proteases secreted in inactive form and activated by
a membrane-bound enteropeptidase
Disaccharidases (in intestinal walls)
Activation of pancreatic peptidases
within the intestine
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3.
Nutrient
Absorption
S.I. highly folded
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Villi (finger-like projections) & microvilli
(appendages of villi) increase absorptive
surface
Small vessels in villi absorb:
 lacteals (lipids pass into)
 & capillaries (other nutrients)
Chylomicrons form: complex of fat,
cholesterol, & protein)
Carried by lacteals; dump into
veins returning to the heart
 Other nutrients—travel to liver via
Hepatic portal vessel
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Large Intestine
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Large intestine (colon)absorb water;
concentrate residue
Bacterial symbiontsgenerate some
vitamins—K, biotin
Cecum-small pouch
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At tip is the Appendix
Feces
Rectum--storage
Anus--elimination
Hormonal Regulation of Digestion
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Gastrin food---> stomach wall ---> gastric juice
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Enterogastrones (duodenum)
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1. Secretin acidic chyme---> secretin --> pancreas to release
bicarbonate (neutralize chyme)
2. Cholecystokinin (CCK)
amino/fatty acids---> pancreas to release enzymes
and gall bladder to release bile
Evolutionary adaptations
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Dentition: an animal’s assortment of teeth
Digestive system length
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Herbivores-longer
Symbiosis
Ruminants
Symbionts: koala-- enlarged
cecum, symbiotic bacteria
ferment finely shredded
eucalyptus leaves.
Ruminants—4 stomach
chambers—microbial action
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Well developed for vegetation: which include deer,
cattle, and sheep.