Transcript Chapter 41

Chapter 41
Animal Nutrition
I. Homeostasis and Nutrition
A. Glucose Regulation
1. Lots of Glucose
2. Insulin is produced by the pancreas
3. Glucose can enter the cells easier and the liver
makes glycogen
4. Glucose levels in the blood drop
5. Glucose gets low
6. Pancreas secretes glucagon which does the
opposite of insulin
7. Glucose is released from glycogen stored
B. Nourishment
1. Undernourishment – body uses protein
for fuel because it is not getting enough
“energy”
2. Overnourishment – body is obese
- if we eat lots of carbs it increases carb
oxidation and fat is not used
- leptin regulates fat levels
C. Essential Nutrients
• Animal’s can not make these and must be
consumed preassembled
• Malnourished if missing one
• 4 classes
1. Essential Amino Acids
2. Essential Fatty Acids
3. Vitamins
4. Minerals
1. Essential Amino Acids
• We can not make every amino acid we
need
• Animals produce complete proteins
• Plants produce incomplete proteins
8 Essential Amino Acids
2. Essential Fatty Acids
• Can’t make certain unsaturated fatty acids
required for phospholipids
• Deficiencies very rare
3. Vitamins
• Organic molecules needed in small
amounts
• Water soluble and fat soluble groups
• 13 essential vitamins in humans
a. Some Water Soluble Vitamins
• Niacin – component of NAD and NADH
• Folic Acid – coenzyme on N.A. and A.A.
metabolism
• B12 – coenzyme in N.A. metabolism and
needed for Red Blood Cells
• C – collagen production and anti-oxidant
(protects phospholipids)
b. Some Fat Soluble Vitamins
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A – vision, skin, protects cell membrane
D – bone growth, absorption of Ca and P
E – antioxidant
K – blood clotting
4. Minerals
• Inorganic molecules needed in small
amounts
• Ca – bone, nerve and muscle function
• P – bone, nucleotide
• Cl and Na – nerve function
• Fe – hemoglobin, electron carrier
• F – maintenance of teeth
• I – thyroid hormone
II. Food and Feeding
• Herbivores, Carnivores, Omnivores
• Most animals are opportunistic feeders
• 4 types of feeders:
A. Types of Feeders
1. Suspension feeders – sift particles from
water / clams and oysters
2. Substrate feeders – live on food source
and eat through it / deposit feeder is one
type / maggots and earthworms
3. Fluid feeder – suck nutrients from host /
mosquitos and leeches
4. Bulk feeder – large pieces of food
consumed / us
III. Basics of Digestion
A. 4 Parts to Digestion
1.
2.
3.
4.
Ingestion
Digestion – (enzymatic) hydrolysis
Absorption
Elimination
B. Types of Digestion
1. Intracellular – use food vacuoles and
enzymes / protists
2. Extracellular
- gastrovascular cavity = very simple
with one opening / digestion and
distribution of nutrients occurs here /
cniderians and planarians
- complete digestive tract = mouth and
anus / one direction with special regions
for digestion
Intracellular
Extracellular – Gastrovascular
Cavity
Extracellular – Complete Digestive
Tract
IV. Mammalian Digestive
System
A. Oral Cavity
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Physical and Chemical Digestion here
Teeth
3 pairs of salivary glands
Saliva contains mucin, buffer, and salivary
amylase
• Forms bolus which is pushed to the
pharynx by the tongue
B. Pharynx
• Junction between the esophagus and
trachea
• Epiglottis found here which keeps food
from entering the trachea
C. Esophagus
• Moves food to stomach via peristalsis
• Peristalsis – muscular pushing of food
through digestive system
• Top is striated (voluntary) and the bottom
is smooth
• Covered with mucus lining
D. Stomach
• Stretchy
• Secretes “gastric juices”
• Pepsinogen (chief cells) is converted to pepsin
by HCl which is made by the parietal cells
• Pepsin is used to break down proteins
• Coated in mucus (mucus cells)
• Produces chyme
• Top has the cardiac orifice and the bottom has
the pyloric sphincter
E. Small Intestines
1.
Basics
- most hydrolysis and absorption of nutrients occurs
here
- starts with the duodenum where bile (fat digestion
and bicarbonate) and pancreatic enzymes (pancreatic
amylase, pancreatic lipidase, and trypsin) enter
- jejunum and ilium are next / enzymes secreted here
-Villi and microvilli absorb with small vessels of the
lymphatic system called lacteal and blood vessels
found inside
- drain into the hepatic portal vessel heading
to liver
Video
2. Macromolecule Digestion
a. Carb digestion – salivary amylase, pancreatic
amylase, maltase, sucrase, lactase
b. Protein digestion – pepsin, dipeptidases,
aminopeptidase / trypsin, chymotrypsin, and
carboxypeptidase are made by pancreas and
turned into their active forms by
enteropeptidase in the small intestines
c. Nucleic Acid digestion – nucleases
d. Fat digestion – lipase breaks it down after bile
emulsification
F. Large Intestines
• Cecum / appendix found here / may be
large in some animals
• Recovers water
• Lots of mutualistic bacteria (E. coli) which
produce vitamins
• Rectum is the end with 2 sphincters, one
involuntary and one voluntary
G. Hormones and Digestion
1. If you see food:
- gastrin is made by the stomach and
released into the blood stream
- stomach secretes acids
- if pH gets too low gastrin is stopped
2. Enterogastrones / Secretin and CCK
- release bicarbonate and help break
down A.A. and F.A.
V. Crazy Ways to Digest
Cows, Rabbits, and Termites