Download Biology II Honors Chapter 41 Guided Notes

LECTURE PRESENTATIONS
For CAMPBELL BIOLOGY, NINTH EDITION
Jane B. Reece, Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, Robert B. Jackson
Chapter 41
Animal Nutrition
Lectures by
Erin Barley
Kathleen Fitzpatrick
© 2011 Pearson Education, Inc.
Overview: The Need to Feed
• Food is taken in, taken apart, and taken up in the
process of animal ____________________
• In general, animals fall into three categories:
– ________________eat mainly plants and algae
– ________________ eat other animals
– ________________regularly consume animals
as well as plants or algae
• Most animals are also ______________feeders
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Concept 41.1: An animal’s diet must supply
chemical energy, organic molecules, and
essential nutrients
• An animal’s diet provides:
– __________________, which is converted into
ATP to power cellular processes
– __________________, such as organic carbon
and organic nitrogen, to synthesize a variety of
organic molecules
– __________________, which are required by
cells and must be obtained from dietary sources
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Essential Nutrients
• There are four classes of essential nutrients:
–
–
–
–
Essential _______________
Essential _______________
________________
________________
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Essential Amino Acids
• Animals require _____ amino acids and can
synthesize about half from molecules in their diet
• The remaining amino acids, the ______________
___________________, must be obtained from
food in preassembled form
• Meat, eggs, and cheese provide all the essential
amino acids and are thus “__________” proteins
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• Most plant proteins are ______________in amino
acid composition
• Individuals who eat only plant proteins need to
eat specific plant combinations to get all the
essential amino acids
• Some animals have adaptations that help them
through periods when their bodies demand
extraordinary amounts of protein
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Essential Fatty Acids
• Animals can synthesize most of the fatty acids
they need
• The __________________must be obtained from
the diet and include certain unsaturated fatty
acids (i.e., fatty acids with one or more double
bonds)
• __________________ in fatty acids are rare
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Vitamins
• ________________are organic molecules
required in the diet in small amounts
• _____________vitamins are essential for
humans
• Vitamins are grouped into two categories: ______
_______________________________
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Table 41.1
Minerals
• _______________ are simple inorganic nutrients,
usually required in small amounts
• Ingesting large amounts of some minerals can
upset ______________________
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Table 41.2
Dietary Deficiencies
• _________________ is the long-term absence
from the diet of one or more essential nutrients
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Deficiencies in Essential Nutrients
• Deficiencies in essential nutrients can cause
____________________________
• “____________” is an engineered strain of rice
with beta-carotene, which is converted to
vitamin A in the body
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Undernutrition
• __________________ results when a diet does
not provide enough chemical energy
• An undernourished individual will
–
–
–
–
–
Use up stored ______ and _________________
Break down its own _______________
Lose ___________ mass
Suffer ______________ deficiency of the brain
________ or suffer irreversible damage
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Assessing Nutritional Needs
• ____________ defects that disrupt food uptake
provide information about human nutrition
– For example, _____________________ causes
iron buildup without excessive iron intake
• Insights into human nutrition have come from
_______________, the study of human health
and disease in populations
• Neural tube defects were found to be the result of
a deficiency in ____________ in pregnant
mothers
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Concept 41.2: The main stages of food
processing are ingestion, digestion,
absorption, and elimination
• ______________ is the act of eating
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Figure 41.5
Mechanical
digestion
1 Ingestion
Nutrient molecules
enter body cells
Chemical
digestion
(enzymatic
hydrolysis)
2 Digestion
Undigested
material
3 Absorption
4 Elimination
Suspension Feeders
• Many aquatic animals are ________________,
which sift small food particles from the water
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Figure 41.6a
Suspension Feeders and Filter Feeders
Baleen
Substrate Feeders
• _________________ are animals that live in or
on their food source
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Figure 41.6b
Substrate Feeders
Caterpillar
Feces
Fluid Feeders
• _________________ suck nutrient-rich fluid from
a living host
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Figure 41.6c
Fluid Feeders
Bulk Feeders
• ______________ eat relatively large pieces of
food
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Figure 41.6d
Bulk Feeders
• ______________is the process of breaking food
down into molecules small enough to absorb
• __________________, including chewing,
increases the surface area of food
• __________________splits food into small
molecules that can pass through membranes;
these are used to build larger molecules
• In chemical digestion, the process of ________
________________ splits bonds in molecules
with the addition of water
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• ___________is uptake of nutrients by body cells
• ______________is the passage of undigested
material out of the digestive system
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Digestive Compartments
• Most animals process food in specialized
___________________
• These compartments reduce the risk of an
animal digesting its own cells and tissues
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Intracellular Digestion
• In _______________, food particles are
engulfed by phagocytosis
• _________________, containing food, fuse with
_____________ containing hydrolytic enzymes
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Extracellular Digestion
• __________________ is the breakdown of food
particles outside of cells
• It occurs in compartments that are continuous
with the outside of the animal’s body
• Animals with simple body plans have a
______________________ that functions in both
digestion and distribution of nutrients
© 2011 Pearson Education, Inc.
Figure 41.7
Mouth
Tentacles
Food
1 Digestive
enzymes released
2 Food
particles broken
down
3 Food particles
engulfed and
digested
Epidermis
Gastrodermis
• More complex animals have a digestive tube with
two openings, a __________ and an ________
• This digestive tube is called a ____________
_________________ or an _________________
• It can have specialized regions that carry out
digestion and absorption in a stepwise fashion
© 2011 Pearson Education, Inc.
Figure 41.8
Esophagus
Crop
Gizzard
Intestine
Pharynx
Anus
Mouth
(a) Earthworm
Foregut Midgut Hindgut
Esophagus
Rectum
Anus
Esophagus
Crop
Stomach
Gizzard
Intestine
Mouth
Anus
Crop
Gastric cecae
Mouth
(b) Grasshopper
(c) Bird
Concept 41.3: Organs specialized for
sequential stages of food processing
form the mammalian digestive system
• The mammalian digestive system consists of an
_______________ and ________________ that
secrete digestive juices through ducts
• Mammalian accessory glands are the ________
____________, the ____________, the _______,
and the_____________________
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• Food is pushed along by ___________, rhythmic
contractions of muscles in the wall of the canal
• Valves called ________________ regulate the
movement of material between compartments
© 2011 Pearson Education, Inc.
Figure 41.9a
Tongue
Oral cavity
Salivary
glands
Pharynx
Esophagus
Liver
Sphincter
Gallbladder
Pancreas
Small
intestine
Large
intestine
Rectum
Anus
Sphincter
Stomach
Duodenum of
small intestine
Figure 41.9b
Mouth
Esophagus
Gallbladder
Liver
Pancreas
Salivary
glands
Stomach
Small
intestine
Large
intestine
Rectum
Anus
Schematic diagram
The Oral Cavity, Pharynx, and Esophagus
• The first stage of digestion is mechanical and
takes place in the _________________
• _______________deliver saliva to lubricate food
• Teeth chew food into smaller particles that are
exposed to salivary _____________, initiating
breakdown of glucose polymers
• Saliva also contains ____________, a viscous
mixture of water, salts, cells, and glycoproteins
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• The tongue shapes food into a ________ and
provides help with swallowing
• The throat, or ____________, is the junction that
opens to both the esophagus and the trachea
• The _______________connects to the stomach
• The _____________(windpipe) leads to the lungs
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• The esophagus conducts food from the ________
down to the ______________ by peristalsis
• Swallowing causes the ______________ to block
entry to the trachea, and the bolus is guided by
the larynx, the upper part of the respiratory tract
• ______________ occurs when the swallowing
reflex fails and food or liquids reach the windpipe
© 2011 Pearson Education, Inc.
Figure 41.10-3
Tongue
Bolus of
food
Pharynx
Epiglottis
up
Glottis
Larynx
Trachea
Esophageal
sphincter
contracted
Esophagus
To lungs To stomach
Relaxed
muscles
Contracted
muscles
Sphincter
relaxed
Stomach
Digestion in the Stomach
• The _____________stores food and secretes
________________, which converts a meal to
acid ______________
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Chemical Digestion in the Stomach
• ___________________ has a low pH of about _,
which kills bacteria and denatures proteins
• Gastric juice is made up of hydrochloric acid
(HCl) and __________________
• Pepsin is a ________________, or proteindigesting enzyme, that cleaves proteins into
smaller peptides
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• ______________ cells secrete ____________
__________________ ions separately into the
lumen (cavity) of the stomach
• Chief cells secrete inactive ________________,
which is activated to pepsin when mixed with
hydrochloric acid in the stomach
• _______________ protects the stomach lining
from gastric juice
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Figure 41.11b
Gastric pits on
interior surface
of stomach
Epithelium
3
Pepsinogen
Pepsin
2
Gastric gland
Mucous cell
Chief cell
Parietal cell
HCl
Chief
cell
1
Cl
H
Parietal
cell
• ____________, lesions in the lining, are caused
mainly by the bacterium Helicobacter pylori
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Stomach Dynamics
• Coordinated contraction and relaxation of
stomach muscle _______ the stomach’s contents
• _____________________ prevent chyme from
entering the esophagus and regulate its entry into
the small intestine
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Digestion in the Small Intestine
• The __________________ is the longest section
of the alimentary canal
• It is the major organ of ________________ and
____________________
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Figure 41.12-4
Carbohydrate digestion
Oral cavity,
Polysaccharides Disaccharides
pharynx,
esophagus
Salivary amylase
Smaller
Maltose
polysaccharides
Stomach
Protein digestion
Proteins
Pepsin
Small polypeptides
Small
intestine
(enzymes
from
pancreas)
Pancreatic amylases
Pancreatic trypsin and
chymotrypsin
Nucleic acid digestion
Fat digestion
DNA, RNA
Fat (triglycerides)
Pancreatic
nucleases
Disaccharides
Smaller
polypeptides
Nucleotides
Pancreatic lipase
Pancreatic carboxypeptidase
Glycerol, fatty acids,
monoglycerides
Small peptides
Small
intestine
(enzymes
from
epithelium)
Disaccharidases
Dipeptidases, carboxypeptidase, and
aminopeptidase
Nucleotidases
Nucleosides
Nucleosidases
and
phosphatases
Monosaccharides
Amino acids
Nitrogenous bases,
sugars, phosphates
• The first portion of the small intestine is the
_________________, where chyme from the
stomach mixes with digestive juices from the
pancreas, liver, gallbladder, and the small
intestine itself
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Pancreatic Secretions
• The ______________produces proteases
_____________ and ________________ that
are activated in the lumen of the duodenum
• Its solution is ______________ and neutralizes
the acidic chyme
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Bile Production by the Liver
• In the small intestine, ________ aids in
digestion and absorption of _________
• Bile is made in the ___________ and stored in
the ________________
• Bile also destroys nonfunctional ____________
cells
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Secretions of the Small Intestine
• The __________________ of the duodenum
produces several digestive enzymes
• _________________ digestion is completed as
peristalsis moves the chyme and digestive juices
along the small intestine
• Most digestion occurs in the duodenum; the
_____________ and __________ function
mainly in absorption of nutrients and water
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Absorption in the Small Intestine
• The small intestine has a huge surface area,
due to __________ and ____________ that are
exposed to the intestinal lumen
• The enormous microvillar surface creates a
______________ that greatly increases the
____ of nutrient absorption
• Transport across the epithelial cells can be
___________or ___________ depending on the
nutrient
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Figure 41.13a
Vein carrying
blood to liver
Muscle layers
Villi
Intestinal wall
Key
Nutrient
absorption
Large
circular
folds
Figure 41.13b
Villi
Microvilli (brush
border) at apical
(lumenal) surface
Lumen
Epithelial
cells
Blood
capillaries
Epithelial
cells
Basal
surface
Lacteal
Key
Lymph
vessel
Nutrient
absorption
• The _______________carries nutrient-rich blood
from the capillaries of the villi to the liver, then to
the heart
• The ___________regulates nutrient distribution,
interconverts many organic molecules, and
detoxifies many organic molecules
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• ______________ cells absorb fatty acids and
monoglycerides and recombine them into
________________
• These fats are coated with phospholipids,
cholesterol, and proteins to form water-soluble
_________________
• Chylomicrons are transported into a __________,
a _______________ vessel in each villus
• Lymphatic vessels deliver chylomicron-containing
______________ to large veins that return blood
to the heart
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Figure 41.14
LUMEN
Triglycerides
OF SMALL
INTESTINE
Epithelial
cell
Fatty acids
Monoglycerides
Triglycerides
Phospholipids,
cholesterol,
and proteins
Chylomicron
Lacteal
Figure 41.14a
LUMEN
Triglycerides
OF SMALL
INTESTINE
Epithelial
cell
Fatty acids
Monoglycerides
Triglycerides
Figure 41.14b
Triglycerides
Phospholipids,
cholesterol,
and proteins
Chylomicron
Lacteal
Absorption in the Large Intestine
• The ___________ of the ________________ is
connected to the small intestine
• The __________________ aids in the
fermentation of plant material and connects
where the small and large intestines meet
• The human cecum has an extension called the
________________, which plays a very minor
role in immunity
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Figure 41.15
Ascending
portion
of colon
Small
intestine
Cecum
Appendix
• A major function of the colon is to ___________
that has entered the alimentary canal
• The colon houses ________________(e.g.,
Escherichia coli) that live on unabsorbed organic
material; some produce ________________
• ______________, including undigested material
and bacteria, become more solid as they move
through the colon
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• Feces are stored in the ____________ until they
can be eliminated through the anus
• Two _________________ between the rectum
and anus control bowel movements
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Concept 41.4: Evolutionary adaptations of
vertebrate digestive systems correlate with
diet
• Digestive systems of vertebrates are _________
on a common plan
• However, there are intriguing _______________,
often related to diet
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Dental Adaptations
• ______________, an animal’s assortment of
teeth, is one example of structural variation
reflecting diet
• The success of mammals is due in part to their
dentition, which is specialized for different diets
• Nonmammalian vertebrates have less
specialized teeth, though exceptions exist
– For example, the teeth of poisonous snakes are
modified as fangs for injecting venom
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Stomach and Intestinal Adaptations
• Many carnivores have large, expandable
_______________
• _____________ and ______________ generally
have longer alimentary canals than carnivores,
reflecting the longer time needed to digest
vegetation
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Figure 41.17
Small intestine
Small
intestine
Stomach
Cecum
Carnivore
Colon
(large
intestine)
Herbivore
Mutualistic Adaptations
• Many herbivores have _____________
chambers, where mutualistic microorganisms
digest cellulose
• The most elaborate adaptations for an
herbivorous diet have evolved in the animals
called ________________
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Figure 41.18
2 Reticulum
1 Rumen
Esophagus
Intestine
4 Abomasum
3 Omasum
Concept 41.5: Feedback circuits regulate
digestion, energy storage, and appetite
• The intake of food and the use of nutrients vary
with an animal’s diet and environment
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Regulation of Digestion
• Each step in the digestive system is activated
________________
• The _____________ division of the nervous
system helps to regulate the digestive process
• The ________________ system also regulates
digestion through the release and transport of
hormones
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Figure 41.19a
1
Food
Liver
Stomach
Gallbladder
Gastric
juices
Gastrin

Pancreas
Duodenum
of small intestine
Key
 Stimulation
 Inhibition
Figure 41.19b
2
Bile
Chyme
CCK

HCO3, enzymes
Secretin

Key
 Stimulation
 Inhibition
CCK

Figure 41.19c
3
Secretin
and CCK

Gastric
juices
Key
 Stimulation
 Inhibition
Regulation of Energy Storage
• The body ____________energy-rich molecules
that are not needed right away for metabolism
• In humans, energy is stored first in the liver and
muscle cells in the polymer glycogen
• Excess energy is stored in adipose tissue, the
most space-efficient storage tissue
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Glucose Homeostasis
• Oxidation of ______________ generates ATP to
fuel cellular processes
• The hormones ______________and _________
regulate the breakdown of glycogen into glucose
• The ________ is the site for glucose homeostasis
– A carbohydrate-rich meal raises ________
levels, which triggers the synthesis of _________
– Low blood sugar causes _______________ to
stimulate the breakdown of glycogen and release
glucose
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Figure 41.20
Transport of
glucose into
body cells
and storage
of glucose
as glycogen
Pancreas
secretes
insulin.
Stimulus:
Blood glucose
level rises
after eating.
Homeostasis:
70–110 mg glucose/
100 mL blood
Breakdown
of glycogen
and release
of glucose
into blood
Stimulus:
Blood glucose
level drops
below set point.
Pancreas
secretes
glucagon.
Regulation of Appetite and Consumption
• Overnourishment causes ___________, which
results from excessive intake of food energy with
the excess stored as fat
• Obesity contributes to _____________ (type__),
cancer of the colon and breasts, heart attacks,
and strokes
• Researchers have discovered several of the
mechanisms that help regulate body weight
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Figure 41.21
Satiety
center
Ghrelin

Insulin

Leptin

PYY

• ____________ regulate long-term and short-term
appetite by affecting a “satiety center” in the brain
• Studies on mice revealed that the hormone ____
plays an important role in regulating obesity
• Leptin is produced by adipose tissue and can
help to ____________________
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Obesity and Evolution
• A species of birds called ___________becomes
obese as chicks; in order to consume enough
protein from high-fat food, chicks need to
consume more calories than they burn
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• The problem of maintaining weight partly stems
from our evolutionary past, when fat hoarding
was a means of ________________
• Individuals who were more likely to eat fatty food
and store energy as adipose tissue may have
been more likely to survive ________________
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Figure 41.UN01
Veins to heart
Hepatic portal vein
Lymphatic system
Mouth
Stomach
Esophagus
Secretions
from salivary
glands
Lipids
Absorbed food
(except lipids)
Small intestine
Secretions
Secretions from liver
from gastric
Secretions from pancreas
glands
Liver
Absorbed
water
Anus
Large
Rectum
intestine