Transcript Digestion & Nutrition

Digestion & Nutrition
Chapter 41
Introductory Question #2
1) From pg. 845, name the four types of feeders
and the organism example shown.
2) How is an essential nutrient different from any
other nutrient? (pg. 849) Give three examples
of a fat-soluble and three examples of a water
soluble vitamin.
3) Name the four stages of food processing. (see
pg. 853).
4) How are the alimentary canals different in an
earthworm, grasshopper, a bird, and a cow
(ruminant animal).
5) Explain what peristalsis is and what causes it
to occur.
Vegetarians must be sure to obtain
all eight essential amino acids
• The eight essential amino acids that adults
require must be obtained from food
– They are easily
obtained from
animal protein
– They can also be
obtained from the
proper combination
of plant foods
ESSENTIAL
AMINO ACIDS
Methionine
Valine
(Histidine)
Threonine
Phenylalanine
Corn
Leucine
Isoleucine
Tryptophan
Lysine
Figure 21.16
Beans and
other
legumes
Table 21.17 (Water-soluble vitamins)
Table 21.17 (Fat-soluble vitamins)
Overview: Food processing occurs in
four stages
Small
molecules
Pieces
of food
Mechanical
breakdown
Nutrient
molecules
enter body
Chemical breakdown
(enzymatic hydrolysis) cells
Undigested
material
Food
1 INGESTION
2 DIGESTION
3 ABSORPTION
4
ELIMINATION
Figure 21.2
Digestion occurs in specialized
compartments
• Food is digested in compartments housing
hydrolytic enzymes
• Most animals have a specialized digestive
tract
• Relatively simple animals have a sac with a
single opening
– This is called a gastrovascular cavity
– Example: hydra
Mouth
Tentacle
Flagella
Hydrolytic
enzymes
Food
particle
Food
(Daphnia,
a water
flea)
Engulfment
Gastro- of food
vascular particle
cavity
Digestion in
food vacuole
Figure 21.3A
• In most animals, the digestive compartment
is an alimentary canal
– This is a tube running from mouth to anus
– This tube is divided into specialized regions that
process food sequentially
Crop
Esophagus
Pharynx
Gizzard
Intestine
Anus
Mouth
EARTHWORM
Wall of intestine
Interior of intestine
Figure 21.3B
Esophagus
Stomach
Gizzard
Anus
Esophagus
Stomach
Gizzard
Intestine
Crop
Gastric pouches
Mouth
GRASSHOPPER
Intestine
Mouth
Crop
Anus
BIRD
Figure 21.3B (cont)
Oral cavity
Mouth
Tongue
Salivary
glands
Pharynx
Esophagus
Liver
Stomach
Pyloric
sphincter
Gallbladder
Pancreas
Small
intestine
Stomach
Small
intestine
Large
intestine
Rectum
Anus
Figure 21.4
Small intestine
Small
intestine
Stomach
Cecum
Colon
(large
intestine)
CARNIVORE
HERBIVORE
Figure 21.12A
• Ruminants such as cows process cellulose
in a four-chambered stomach
Intestine
3 Omasum
1 Rumen
Esophagus
Rumen
4 Abomasum
2 Reticulum
Figure 21.12B
The human digestive system
consists of an alimentary canal
and accessory glands
• When food is swallowed, it is moved through
the alimentary canal by peristalsis
– Peristalsis is rhythmic muscle contraction in the
walls of the digestive tract
– Ringlike sphincter muscles regulate the passage
of food
The esophagus squeezes food
along to the stomach
• Peristalsis in the esophagus moves food
boluses into the stomach
Circular
muscle layer
Bolus of
food
Longitudinal
muscles
contract,
shortening
passageway
ahead of bolus
Longitudinal
muscle layer
Relaxed
muscles
Circular
muscles
contract,
constricting
passageway
and pushing
bolus down
Relaxed
muscles
Stomach
Figure 21.7
Interior surface
of stomach
Food particle
Pits
Gastric juice
(mucus, HCI,
and pepsinogen)
3
Epithelium
Gastric
juice
Pepsinogen
2
Mucous
HCI
cells
Pepsin (active
enzyme)
Pyloric
sphincter
STOMACH
Gastric
gland
1
Chief cells
Parietal cells
Figure 21.8
Bile
Liver
Stomach
Gallbladder
Bile
Duodenum of
small intestine
Acid chyme
Pancreas
Figure 21.10A
• Enzymes from the walls of the small
intestine complete the digestion of many
nutrients
Table 21.10
INTERIOR OF INTESTINE
Blood vessel
with blood
en route to
the liver
Nutrient
absorption
Nutrient
absorption
Microvilli
Epithelial
cells
Lumen
Muscle
layers
Circular folds
Villi
Blood
capillaries
Lymph
vessel
EPITHELIAL
CELLS
Nutrient
absorption
INTESTINAL WALL
VILLI
Figure 21.10B
Large Intestine Reclaims Water
• Undigested
material passes
to the large
intestine, or
colon
Large
intestine
(colon)
End
of small
intestine
– Water is
absorbed
– Feces are
produced
Small
intestine
Rectum
Anus
Nutrient
flow
Appendix
Cecum
Figure 21.11
Ch. 44 & 45 - Digestion & Fluid Balance
1. What organism is used by Dr. Carol Beuchat to
illustrate how fluid is regulated and the role played
by the urinary tract in maintaining homeostasis?
(1st segment)
2. How is a complete digestive system different from
an incomplete one? What function does each
segment (region) of the digestive system have?
3. Name two enzymes mentioned by Dr. Sokolowski
that play a role in the digestive system. How is the
diet of a dog different from a cat? What are the
nutritional needs for a cat and dog? What is the
name of the café mentioned in the video?
4. The final segment discusses the role the kidneys
play in maintaining homeostasis. What kind of
machine is the patient connected to? **Write the title
for each segment and FIVE statements for each
Video: Nutrition & Digestion
Write 10 statements
Digestion begins in the oral cavity
• The teeth break up food
• Saliva moistens it
• Salivary enzymes begin the hydrolysis of
starch
• The tongue pushes the chewed food into the
pharynx
TEETH
Incisors
Canine
Premolars
Molars
Tongue
“Wisdom”
tooth
Salivary
glands
Opening of a
salivary gland duct
Figure 21.5
The food and breathing passages
both open into the pharynx
• The swallowing reflex moves food from the
pharynx into the esophagus
– At the same time, food is kept out of the trachea
Bolus of food
Epiglottis
up
Tongue
Pharynx
Epiglottis
down
Larynx
Trachea
(windpipe)
Sphincter contracted
Esophageal
sphincter
Larynx
down
Larynx
up
Esophagus
Esophagus
Sphincter relaxed
Sphincter contracted
Figure 21.6
The stomach stores food and
breaks it down with acid and
enzymes
• The stomach mixes food with gastric juice
– The gastric juice contains pepsin, which begins
the hydrolysis of protein
Bacterial Infections can cause
Ulcers
• New evidence suggests that a spiral-shaped
prokaryote causes gastric ulcers
– Helicobacter pylori growth erodes protective
mucus and damages the stomach lining
The small intestine is the major
organ of chemical digestion
and nutrient absorption
• Alkaline pancreatic juice neutralizes stomach
acids
– Its enzymes digest polysaccharides, proteins,
nucleic acids, and fats
• Bile emulsifies fat droplets for attack by
pancreatic enzymes
– It is made in the liver and stored in the gall
bladder
• The lining of the small intestine is folded and
covered with tiny, fingerlike villi
– Villi increase the absorptive surface
• Nutrients pass through the epithelium of the
villi and into the blood
– The blood flows to the liver
– The liver can store nutrients and convert them to
other substances the body can use
Adaptations of vertebrate
digestive systems reflect diet
• Herbivores and omnivores generally have
longer alimentary canals than carnivores
– Plant matter is more difficult to digest than meat
– Nutrients in vegetation are less concentrated
than in meat
• Some mammals house cellulose-digesting
microbes in the colon or cecum
– The cecum is a pouch where the large and small
intestines connect
– Examples: horses and elephants
• Other mammals re-ingest their feces to
recover nutrients
– Examples: rabbits and some rodents
A healthful diet satisfies three
needs
• An animal’s diet provides
– fuel for its activities
– raw materials for making the body’s own
molecules
– essential nutrients that the body cannot make
Chemical energy powers the
body
• Once nutrients are inside cells, they can be
oxidized by cellular metabolism to generate
energy
– This energy is in the form of ATP
• The energy a
resting animal
requires each day
to stay alive is its
basal metabolic rate
(BMR)
Figure 21.14
• More energy
is required for
an active life
– Excess
energy is
stored as
glycogen or
fat
Table 21.14
Body Fat and Fad Diets
• The human body tends to store excess fat
molecules instead of using them for fuel
• A balanced diet includes adequate amounts
of all nutrients
• Fad diets are often ineffective and can be
harmful
Table 21.15
A healthful diet includes 13
vitamins
• Most of these vitamins function as
coenzymes
Essential minerals are required
for many body functions
• Minerals are elements other than carbon,
hydrogen, oxygen, and nitrogen
– They play a variety of roles in the body
Table 21.18
What do food labels tell us?
• Food labels
provide
important
nutritional
information
about
packaged foods
Figure 21.19
Diet can influence cardiovascular
disease and cancer
• Choice of diet may reduce the risk of
cardiovascular disease and cancer
BEHAVIORAL
RISK FACTORS
Fatty diet
UNAVOIDABLE
RISK FACTORS
High
blood
cholesterol
High
blood
pressure
Lack of
exercise
Aging
Family history
CARDIOVASCULAR
DISEASE
Smoking
Being male
Figure 21.20
Table 21.20
Bile
Liver
Stomach
Gallbladder
Bile
Duodenum of
small intestine
Acid chyme
Pancreas
Figure 21.10A
Video:
Laparoscopic Cholecystectomy
*Write 10 Statements from the
video
Assignments Packet
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Bold list of Terms from Chapter 42
Print out of Quizzes Online (x3)
– Ch. 39, 40, and 41
AP Test: MC Questions & (2) Essays
IB Syllabus Review (13 topics w/three areas)
IB Test: (3) Sections-paper 1, 2, and 3
Videos (x5)
-Digestive & Nutrition
-Heart Attack
-Immune & Lymphatic
-Endocrine & Homeostasis
-Laparoscopic Cholecystectomy
-Bacteria, Protists, & Viruses
IQ’s (x4)
-Chapter 39 (2)
-Chapter 40 (1)
-Chapter 41 (1)
Classification of Animal Phyla
Drosophila Lab
Extra credit: 12 AP Labs from Website
• A sound diet supplies
– enough raw materials to make all the
macromolecules we need
– the proper amounts of prefabricated essential
nutrients
– enough kilocalories to satisfy our energy needs
Getting Their Fill of Krill
• Animals obtain and
process nutrients in a
variety of ways
• Humpback whales eat
small fishes and
crustaceans called krill
– This painting shows how
the whales corral their
food using “bubble nets”
• Humpback whales strain their food from
seawater using large, brushlike plates called
baleen
– When they feed, they take in large amounts of
seawater in which the fish and krill live
– They must filter out the water in order to get a
meal
• In a typical day, a humpback whale’s
digestive system will process as much as 2
tons of fish and krill
– They store the excess energy they harvest in the
form of blubber
– In about 4 months, a humpback whale eats,
digests, and stores as fat enough food for an
entire year
Animals ingest their food in a
variety of ways
• Animal diets are highly
varied
– Herbivores are plant-eaters
– Carnivores are meat-eaters
– Omnivores eat both plants
and other animals
Figure 21.1A
• Most animals ingest chunks of food
Figure 21.1E
– Some animals are
suspension feeders,
consuming particles
from water
– Some are substrate
feeders, living in or on
their food source
Figure 21.1B, C
– Some are fluid
feeders, sucking
liquids
Figure 21.1D