Chapter 41:
Animal Nutrition
Jonah Lewis
AP Biology
Block C
I. Homeostasis and The Energy
Budget
• Glucose Regulation
o
Glycogen: A polymer made of many glucose
units that acts as a reserve of energy for the
body. When in need body will burn glycogen to
produce ATP.
• Caloric Imbalance
o Undernourishment:
Chronically deficient in
calories
o Overnourishment: Excessive food intake,
often leading to obesity
 Obesity leads to many health problems,
especially cardiovascular problems
 Leptin: Hormone that regulates appetite in
mammals
 With weight loss, Leptin level increases,
increasing appetite
II. Diet must supply carbon
skeletons and essential nutrients
• Malnourished: Diet is missing one or
more essential nutrients
• Essential Amino Acids: Amino acids that
must be received from food, can not be
made in body
o
Protein deficiency: Malnourishment caused
by lack of essential amino acids
• Essential Fatty Acids: Fatty acids body
can not make for itself
• Vitamins: Organic molecules required in
diet in relatively small amounts
o
Fat Soluble: Accumulate in fat
 A,D,E, and K
o
Water Soluble: Are not stored in body for long
periods of time
 B complex: coenzymes
 Vitamin C: Production of Connective Tissue
• Minerals: Simple inorganic nutrients
Calcium and Phosphorus: Maintenance of
bone
o Magnesium, Iron, Zinc, Copper, Manganese,
Selenium, Molybdenum: Part of structures of
some enzymes.
o Sodium, Chlorine, Potassium: Nerve
functioning and osmotic balance between cells
and in interstitial fluid
o
III. Food Processing in body
• Ingestion: The act of Eating
• Digestion: Process of breaking food down into
molecules small enough for body to absorb
o
Enzymatic hydrolysis: Bonds broken with addition of
water
• Absorption: Absorption of digested molecules
• Elimination: Undigested material passes out of
system
• Intracellular Digestion: Digestion within a
cell, not widely used in animals
• Extracellular Digestion: Breakdown of
food outside of cell, in a digestive sac
Gastrovascular cavity: a digestive sac that
functions as both a place for digestion and to
distribute nutrients
o Complete Digestive Tract (Alimentary Canal):
Digestive tube stretching between two
openings
o
IV. Mammalian Digestive System
• Peristalsis: Contraction of smooth muscle
that push food down alimentary tract
• Accessory glands
o
Salivary glands, pancreas, liver, and gallbladder
• Oral Cavity: Mechanical and some
chemical digestion of food
o
Salivary Amlyase: enzyme in saliva that breaks
down starch
• Pharynx: Throat; leads to both the windpipe and
esophagus
When swallowing the epiglottis covers the opening to
the windpipe so food only goes to the esophagus
o Esophagus: conducts food from pharynx to the
stomach by muscle contractions (peristalsis)
o
• The Stomach: Stores food and performs
preliminary digestion
o
o
Inside covered in mucous as to not self-digest
Churns food with Gastric juice
 Pepsin: Enzyme that aids in digestion of proteins
 Secreted by Chief Cells as inactive Pepsinogen
 Parietal cells: Secrete hydrochloric acid which activates the
pepsinogen in the stomach
• The Small Intestine: Longest section of
alimentary canal, where most digestion and
absorption occurs
Duodenum: Beginning of small intestine where acid
chyme from stomach mixes with more digestive juices
o Bile: produced by liver and stored in gallbladder, aid
in digestion
o Villi and Microvilli: Projections into small intestine
that greatly expands surface area to allow for
absorption of nutrients.
o Hepatic Portal Vessel: Blood vessel that leads directly
to liver from Small Intestine
o
• Large Intestine (The Colon)
Cecum: Pouch where bacteria live to help
break down cell walls
o Recovers water from feces (waste of digestive
tract) and sends it back to body
o Rectum: Terminus of large intestine where
feces are stored until elimated from body
o
V. Evolutionary Adaptations to
Digestive System
• Dentition: Arrangement of teeth
o
Teeth show kind of food an animal eats, as
different kind of teeth tear different kinds of
food
• Longer alimentary canals are common for
herbivores because cell walls are harder
to digest