Transcript Lecture #18 Date - Marquette University High School

• Chapter 41
Animal Nutrition
Nutritional requirements
• Undernourishment: caloric
deficiency
• Overnourishment (obesity):
excessive food intake
• Malnourishment: essential
nutrient deficiency
• Essential nutrients: materials
that must be obtained in
preassembled form
• Essential amino acids: the 810 amino acids that must be
obtained in the diet
(Arginine, Histidine – Infants)
• Essential fatty acids:
unsaturated fatty acids
• Vitamins: organic
coenzymes
• Minerals: inorganic cofactors
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)
Bulk-feeders: eat large pieces of
food (most animals)
Overview of food processing
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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
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
Mammalian
digestion
• Oral cavity
•salivary amylase
•bolus
• Pharynx
•epiglottis
• Esophagus
• Stomach
•gastric juice
•pepsin/pepsinogen (HCl)
•acid chyme
•pyloric sphincter
Figure 41.3 Homeostatic regulation of cellular fuel
1 When blood glucose
level rises, a gland called
the pancreas secretes insulin,
a hormone, into the blood.
2 Insulin enhances the
transport of glucose into body
cells and stimulates the liver
and muscle cells to store
glucose as glycogen. As a
result, blood glucose level
drops.
STIMULUS:
Blood glucose
level rises
after eating.
4 Glucagon promotes
the breakdown
of glycogen in
the liver and
there lease of
Glucose into the
blood,increasing
blood glucose level.
Homeostasis:
90 mg glucose/
100 mL blood
STIMULUS:
Blood glucose
level drops
below set point.
3 When blood glucose
level drops, the pancreas
secretes the hormone
glucagon, which opposes
the effect of insulin.
Figure 41.19 The duodenum
Liver
Bile
Gallbladder
Stomach
Acid chyme
Intestinal
juice
Pancreatic juice
Pancreas
Duodenum of
small intestine
Mammalian digestion
• 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
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Large intestine (colon)
Cecum
Appendix
Feces
Rectum/anus
Figure 41.22 Hormonal control of digestion
Enterogastrone secreted by the
Liver
duodenum inhibits peristalsis and
acid secretion by the stomach,
thereby slowing digestion when
acid chyme rich in fats enters the
duodenum.
Enterogastrone
Gallbladder
Gastrin
CCK
recirculates via the bloodstream
back to the stomach, where it
stimulates the production
of gastric juices.
Stomach
Amino acids or fatty acids in the
duodenum trigger the release of
cholecystokinin (CCK), which
stimulates the release of digestive
enzymes from the pancreas and bile
from the gallbladder.
Gastrin from the stomach
Pancreas
Secretin
Duodenum
CCK
Key
Stimulation
Inhibition
Secreted by the duodenum,
secretin stimulates the pancreas
to release sodium bicarbonate,
which neutralizes acid chyme
from the stomach.
Mammalian digestion
• Small intestine •duodenum •bile
• Intestinal digestion: a-carbohydrate b-protein c- nucleic acid
d-fat
Mammalian digestion
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Villi / microvilli
Lacteal (lymphatic)
Chylomicrons (fats mixed with cholesterol)
Hepatic portal vessel
Evolutionary adaptations
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Dentition: an animal’s assortment of teeth
Digestive system length
Symbiosis
Ruminants