Get documents about "Slide 1 - Troy High School
Shared by: dfhdhdhdhjr
-
Stats
- views:
- 4
- posted:
- 1/31/2013
- language:
- English
- pages:
- 52
Document Sample
Introductory Question #6
1) Name the four stages of food processing. (see pg.
853).
2) From pg. 845, name the four types of feeders and the
organism example shown.
3) How are the alimentary canals different in an
earthworm, grasshopper, a bird, and a cow (ruminant
animal).
4) Explain what peristalsis is and what causes it to occur.
5) Name the cells that line the stomach which secrete
HCl and pepsin. What are folds in the stomach called?
6) What function do the villi serve in the lining of the
intestines? Name the (3) segments of the small
intestines and the (4) regions of the large intestines.
7) 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.
Digestion & Nutrition
Chapter 41
Overview: Food processing occurs in
four stages
Small
molecules
Pieces
of food Nutrient
molecules
Chemical breakdown enter body
Mechanical (enzymatic hydrolysis) cells Undigested
breakdown 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
Hydrolytic
Flagella enzymes
Food
particle
Engulfment
Food Gastro- of food
(Daphnia, vascular particle
a water cavity
flea) 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 Gizzard
Esophagus Intestine
Pharynx
Anus
Mouth
EARTHWORM
Wall of intestine
Interior of intestine
Figure 21.3B
Grinding
Esophagus
Stomach
Gizzard Anus
Esophagus
Stomach
Intestine Gizzard
Crop
Intestine
Mouth Gastric pouches
GRASSHOPPER Mouth
Crop
Anus
BIRD
storage
Figure 21.3B (cont)
• Ruminants such as cows process cellulose
in a four-chambered stomach
Re-absorption water
Intestine 3 Omasum 1 Rumen Fermentation/microorganisms
Esophagus
Rumen
4 Abomasum 2 Reticulum
Size sorter/microorganisms
Releases acids/digestive enzymes
Figure 21.12B
• 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
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
Small intestine
Small
intestine Stomach
Large to
house
Cecum
bacteria to
break down
plant
material
Colon
(large
intestine)
CARNIVORE HERBIVORE Figure 21.12A
Oral cavity
Mouth
Tongue Pharynx
Salivary
glands
Esophagus
Liver
Stomach
Pyloric
sphincter
Stomach
Gall-
bladder
Small
Pancreas intestine Small
intestine
Large
intestine
Rectum
Anus Figure 21.4
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
“Wisdom”
tooth
Tongue
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
Tongue
Epiglottis Epiglottis
up down
Pharynx
Larynx
Esophageal Larynx Larynx
sphincter up down
Trachea Esophagus
(windpipe) Esophagus
Sphincter contracted Sphincter relaxed Sphincter contracted
Figure 21.6
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 Relaxed
muscle layer muscles
Circular Relaxed
muscles muscles
contract,
Bolus of constricting
food passageway
and pushing
bolus down
Longitudinal
muscles
contract,
shortening
passageway
ahead of bolus
Stomach
Longitudinal
muscle layer
Figure 21.7
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
Interior surface Pits
of stomach Gastric juice
(mucus, HCI,
Food particle and pepsinogen)
3
Epithelium
Gastric
juice Pepsinogen Pepsin (active
2 enzyme)
Mucous
cells HCI
Pyloric
sphincter
Gastric 1
STOMACH Chief cells
gland
Parietal cells
Figure 21.8
The small intestine is the major organ of
chemical digestion and nutrient absorption
DUODENUM:
• 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
Bile
Liver
Gall- Stomach
bladder
Bile Acid chyme
Duodenum of Pancreas
small intestine
Figure 21.10A
• 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
• (1) the Duodenum: a section
that receives secretions from
the pancreas and liver; a
receiving area for chemicals
and partially digested food from
the stomach;
• (2) the Jejunum: where most
of the nutrients are absorbed
into the blood and considered
to be roughly 40% of the small
gut in man
• (3) the Ileum: where the
remaining nutrients are
absorbed before moving into
the large intestine; considered
to be about 60% of the
intestine in man
• Enzymes from the walls of the small
intestine complete the digestion of many
nutrients
Table 21.10
INTERIOR OF INTESTINE
Blood vessel
with blood Nutrient
en route to absorption
the liver
Nutrient
absorption
Microvilli
Epithelial
cells
Lumen
Muscle
layers
Blood
Circular folds capillaries
Villi Lymph EPITHELIAL
vessel CELLS
Nutrient
absorption
INTESTINAL WALL VILLI
Figure 21.10B
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
Large Intestine Reclaims Water
• Undigested Large
intestine
material passes (colon)
to the large
intestine, or
colon End
of small Small
– Water is intestine intestine
Rectum
absorbed
Anus
– Feces are Nutrient
flow
produced Appendix
Cecum
Figure 21.11
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
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
ESSENTIAL
obtained from AMINO ACIDS
animal protein Methionine
– They can also be Valine
(Histidine)
obtained from the Threonine
proper combination Phenylalanine
of plant foods Corn Leucine
Isoleucine
Beans and
Tryptophan other
legumes
Lysine
Figure 21.16
Table 21.17 (Fat-soluble vitamins)
Table 21.17 (Water-soluble vitamins)
Table 21.18
Diet can influence cardiovascular
disease and cancer
• Choice of diet may reduce the risk of
cardiovascular disease and cancer
BEHAVIORAL UNAVOIDABLE
RISK FACTORS RISK FACTORS
Fatty diet High High Aging
blood blood
cholesterol pressure
Lack of Family history
exercise
CARDIOVASCULAR
DISEASE
Smoking Being male
Figure 21.20
Table 21.20
• 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”
Video #5-Digestion & Fluid Balance (Ch. 41)
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?
5. **Write the title for each segment and FIVE statements
for each segment.
Video#6:
Laparoscopic Cholecystectomy
*Write 10 Statements from the
video
