Download Digestion - Spring Branch ISD

P 665
Sponges:
Phylum Porifera
Sponges:
Feeding
Animal Systems:
Digestion
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Phylum Cnidaria: Feeding
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Carnivores
Cnidocytes – stinging cells located on
tentacles
nematocysts – poison-filled stinging
structure that paralyze or kill prey
gastrovascular cavity - for digestion
Central mouth surrounded by numerous
tentacles
filter feeders – take in tiny particles of food
from water
pores - openings where water enters
choanocytes – cells with a flagella that trap
and engulf tiny particles and move water
through sponge
osculum – a large opening where water and
wastes exit
Figure 26–12 The Polyp and Medusa Stages
Section 26-3
Epidermis
Mesoglea
Gastroderm
Tentacles
Mesoglea
Gastrovascular cavity
Mouth/anus
Mouth/anus
Gastrovascular
cavity
Tentacles
Medusa
Polyp
Go to
Section:
1
Flatworms: Phylum Platyhelminthes
Feeding/Digestion
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Have a single opening or mouth
located at the end of a muscular tube
called the pharynx which can be
extended when feeding
Pathway: pharnyx, mouth, digestive
cavity (intestine) where food diffuses
to cells of body
Carnivores, some are parasites
Parasitic flatworms have hooks and
suckers for attachment to host
Roundworms: Phylum Nematoda
Feeding/Digestion
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Roundworms – some are
parasitic
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Hookworm is an intestinal parasite of humans
that causes mild diarrhea and abdominal pain
The barely visible larvae penetrate the skin
(often through bare feet)
carried to the lungs, go through the respiratory
tract to the pharnyx, are swallowed, and
eventually reach the small intestine.
In the small intestine, the larvae develop into
half-inch-long worms, attach themselves to the
intestinal wall, and suck blood.
can either be carnivorous, herbivorous, or
parasitic
Some have grasping mouth parts
Nutrients are transported throughout body via
fluid in pseudocoelom
Pathway: mouth, pharynx, intestines, anus
Roundworms – some
are parasitic
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Ascaris - most common human worm infection.
tropical and subtropical areas where sanitation
and hygiene are poor
An estimated 1.5 billion humans infected; rare in
U.S.
Infection occurs when a person accidentally
ingests (swallows) infectious Ascaris eggs
Once in the small intestines, immature worms
hatch from the eggs
The larvae are carried through the lungs and
then to the throat where they are swallowed
Once swallowed, they reach the intestines and
develop into adult worms.
Adult female worms lay eggs that are then
passed in feces
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Roundworms
Roundworms
Elephantiasis
•worms block the body's lymphatic system-a network of channels, lymph nodes, and
organs that helps maintain proper fluid
levels in the body by draining lymph from
tissues into the bloodstream.
•This blockage causes fluids to collect in the
tissues, which can lead to great swelling,
called "lymphedema."
Segmented worms: Phylum
Annelida Feeding/Digestion
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Pathway: mouth, pharynx, crop, gizzard,
intestines, anus
Extends pharynx to get food
Crop – stores food
Gizzard – grinds food
Some filter feeders (aquatic)
Some predators with jaws
Phylum Arthropoda:
Feeding/Digestion
•Pathway: mouth/foregut, pharynx,
esophagus, stomach/midgut, hindgut,
anus
•Midgut - (where special enzymes
digest food also where absorption
occurs)
•Many different types of mouthshighly adapted to food source
Chelicerae
•Spiders have venom –poisonus fluid
•Some have chelicerae (ex: spiders)
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Phylum Mollusca:
Feeding/Digestion
Arthropod feeding
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Termites – destroy structures
Ticks/mosquitoes – transmit disease
Bees- aids in flowering plant reproduction
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Pathway:
2 openings
Have siphon that takes in
water/particles
Snails have a radula- contains
hundreds of tiny teeth
some can drill through shells
for food
Octopus has sharp beak for
tearing food
Contain muscular foot
(tentacles are modified
feet)
Mollusks - filter feeding
Mollusk - snails have a
radula for scraping algae
Mollusks - radula
Phylum Echinodermata
Feeding & Digestion
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Mollusks occupy many
trophic levels:
Carnivores
Parasites
Herbivores
Filter feeders
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Extracellular digestion
 starfish feed on bivalves by opening
shells, pushing stomach inbetween shells
and partially digesting the organism
before pulling the stomach back to
original position to complete digestion.
Occupy variety of trophic levels including,
carnivore, herbivore, detritivores
Contain digestive glands in arms
Feathery star that catches food
with its tentacles and then eats
each one at a time.   
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Echinoderms
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Variety of niches as
part of an ecosystem
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Predators thus controlling
the number of organisms
in a population
Control algae population
Some feed on coral
which is a problem in
reefs.
Crown-of-Thorns starfish above has eaten the coral in
the white area. It is termed a feeding scar.
Vertebrate chordates have
similar digestive pathways
Phylum Chordata:
Fish - Digestion
Chordate Cladogram
Section 30-1
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Birds
Amphibians
Mammals
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Reptiles
Fishes
Nonvertebrate
chordates
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Pathway: mouth -> esophagus -> stomach ->
pyloric ceca -> intestine ->anus
Liver, gall bladder and pancreas – secrete
enzymes into digestive system that help break
down food
All modes of feeding (herbivore, carnivore, etc)
Invertebrate ancestor
Go to
Section:
Phylum Chordata: Amphibian
Digestion
Figure 30–11 The Anatomy of a Fish
Section 30-2
Kidney
Pyloric
cecum
Stomach
Vertebra
Muscle
Esophagus
Swim
bladder
Spinal Gills
cord
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Brain
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Mouth
Pathway: mouth,
esophagus, stomach,
small intestine, large
intestine, cloaca
Have liver, gallbladder,
pancreas
Operculum
Urinary
bladder
Heart
Anus
Reproductive
organ
Pancreas
Intestine
Gallbladder
Liver
Go to
Section:
5
Amphibian digestion
Phylum Chordata:
Reptilian Digestion
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Phylum Chordata:
Digestion
Bird
Pathway: mouth, esophagus, crop,
stomach/gizzard (2 part), intestines, cloaca
Have liver, gallblader, pancreas
Use large amounts of calories, therefore they
eat a lot!
Beak adapted to food source
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Phylum Chordata:
Mammals Digestion
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Complete,
complex,
digestive system
Specialized
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Teeth
Jaws
Pathway: (similar to amphibians);
mouth, esophagus, stomach, small
intestine, large intestine, cloaca
Have liver, gallbladder, pancreas
Some metabolize food slowly
(snakes) and only need to eat once
a month after a large meal
Some are herbivores, some
carnivores
Bird
Digestion
Figure 33–8 The Digestive Systems
of Vertebrates
Section 33-3
Esophagus
Shark
Salamander
Lizard
Pigeon
Cow
Stomach
Intestine
Liver
Gallbladder
Pancreas
Cloaca
Crop
Gizzard
Cecum
Rectum
Go to
Section:
6
Human nutrition &
digestion
6 major nutrients:
1.
2.
3.
4.
5.
6.
Water
Carbohydrates
Fats
Proteins
Vitamins
Minerals
Concept Map
Section 38-1
Nutrients
include
http://www.mypyramid.gov/
Carbohydrates
Fats
Proteins
Vitamins
Minerals
include
are made of
are made using
include
include
Video
Simple
Complex
such as
such as
Sugars
Starches
Amino
acids
Fatty Acids
Calcium
Iron
Glycerol
Fat-soluble
Nutrient Label Quiz
Watersoluble
Go to
Section:
Human Digestion
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Mechanical and chemical breakdown of food into
molecules
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Food molecules are broken down by enzymes
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Digestive enzyme chart on p.981
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Peristalsis – rhythmic contractions of smooth
muscle throughout entire digestive system
Figure 38–10 The Digestive System
Section 38-2
Mouth
Pharynx
Salivary glands
Esophagus
Liver
Gallbladder
(behind liver)
Digestion Pathway
1. Mouth
Mechanical and chemical digestion
 Salivary glands produce saliva
 Saliva contains amylase, an enzyme that
breaks down starch
Stomach
Pancreas (behind
stomach)
Large intestine
2. Pharynx
Small intestine
Rectum
Video
Go to
Section:
7
Digestion Pathway
3. Esophagus
Connects mouth to stomach
Digestion Pathway
4. Stomach
Mechanical and chemical digestion
Breaks proteins apart
Cells secrete HCl (an acid) and proteases
Ph is approx 3!!
Contains chyme – soupy fluid of food, HCl, and
enzymes
Digestion Pathway
Figure 38–14 The Small Intestine
Section 38-2
Small Intestine
5. Small Intestine
Absorbs nutrients into blood stream
contains folds with villi and microvilli to
increase surface area for absorption
6 meters long
Duodenum – first section; completes digestion
Villus
Circular folds
Epithelial cells
Villi
Capillaries
Lacteal
Vein
Artery
Go to
Section:
8
P. 983
Digestion Pathway
6. Large intestine (Colon)
1 meter long
3 straight segments
compacts undigested materials, absorbs
water, and excretes waste from body
Contains “helpful” bacteria
Other organs involved in
digestion:
Liver
 Produces bile
Supplies quick energy by releasing sugar into
blood
 Detoxifies alcohol and poisons
Gall Bladder – stores bile
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Figure 38–13 The Liver and the Pancreas
Section 38-2
Other organs involved in
digestion:
Pancreas
Liver
Gallbladder
Duodenum
Bile duct
Pancreas
Pancreatic duct
 Regulates blood sugar by producing:
 Insulin – lowers blood sugar levels
 Glugagon – increases blood sugar levels
To rest of small intestine
Go to
Section:
10