Download Digestive Systems

Feeding
Digestive
Lamprey uses teeth on tongue to cut hole in fish
Produces anticoagulant chemical in saliva
Lamprey ingests fish’s body fluids
Hagfish are deep water scavengers
Basic digestive system (See invertebrates)
Teeth are modified scales
Different species have different shape teeth
depending upon food type…
Pointy teeth for catching small fish
Blade like teeth for biting off pieces of flesh
Flat teeth for crushing shells
The largest ones are filter feeders
Basic digestive system with a “Spiral Valve” in the
intestine
Some carnivores, some herbivores, some omnivores.
Basic digestive system
• Food passes through the mouth and esophagus,
into the stomach.
• In the stomach, the food is partially broken down.
Stomach
Esophagus
Mouth
• In many fishes, the food is further processed in
fingerlike pouches called pyloric ceca.
• The pyloric ceca secretes digestive enzymes and
absorbs nutrients from the digested food.
Pyloric cecum
• The liver and pancreas add enzymes and other
digestive chemicals to the food as it moves
through the digestive tract.
Liver
Pancreas
Form and Function in Fishes
• The intestine completes the process of digestion
and nutrient absorption.
Intestine
Only show “Intestine” label on this slide.
Form and Function in Fishes
• Others wastes are removed by kidneys.
• The kidneys of marine fishes concentrate
wastes and return water to the body.
Kidney
Some carnivores, some herbivores, some omnivores.
Basic digestive system
Larva - Some carnivores, herbivores, and omnivores
Many have scraping teeth for algae
Herbivores have long intestines
Adults - almost all carnivores
Simple teeth
Frogs and toads catch food
with long sticky tongue
Mouth
Esophagus
Stomach
Small intestine
Stomach
Feeding
Digestive
Some carnivores, herbivores, and omnivores
Simple teeth
Snakes all carnivores
Some have modified teeth to deliver venom that subdues
prey and begins digestion
Some constrict prey
Crocodilians have crop-gizzard system to grind food
Form and Function
in
Reptiles
Liver
Heart
Kidney
Cloaca
Bladder
Digestive
tract
Lung
Some carnivores, herbivores, and omnivores
No teeth
Some have crop-gizzard system to grind food
Form, Function, and Flight
Esophagus
Crop
When a bird eats,
food moves down
the esophagus and
is stored in the crop.
Form, Function, and Flight
First chamber of stomach
Gizzard
Moistened food passes
to the stomach, a twopart chamber.
Form, Function, and Flight
First chamber of stomach
Gizzard
The first chamber
secretes acid and
enzymes.
Form, Function, and Flight
First chamber of stomach
Gizzard
The partially digested
food moves to the
second chamber, the
gizzard.
Form,
The muscular walls of the
gizzard and
squeeze
the contents,
Function,
Flight
while small stones grind the
food.
Gizzard
Some carnivores, herbivores, and omnivores
Highly developed teeth
Usually have multiple types of teeth for different jobs
Incisors - holding and cutting food
Molars - grinding and crushing food
Some herbivores have modified “stomach” chambers
called a rumen for bacterial digestion of cellulose
Form and Function in
Mammals
• Jaws and Teeth of Mammals
Carnivore
Herbivore
Canines
Jaw
joint
Wolf
Incisors
Molars and premolars
Jaw
joint
Horse
• Canines: Canines are pointed teeth.
Carnivores use them for piercing, gripping,
and tearing. In herbivores, they are reduced
or absent.
Canines
Wolf
Horse
• Incisors: Chisel-like incisors are used for
cutting, gnawing, and grooming.
Wolf
Incisors
Horse
• Molars crush and grind food. The ridged
shape of the wolf’s molars and premolars
allows them to interlock during chewing,
like the blades of scissors. The broad,
flattened molars and premolars of horses are
adapted for grinding tough plants.
Wolf
Molars and premolars
Horse
Feeding
• Vertebrate Digestive Systems
Shark
Salamander
Lizard
Feeding
• Vertebrate Digestive Systems
Pigeon
Cow
The limbs and digits (fingers and toes) of many
mammals are adapted to their particular way of life.
Note the variety of lengths and shapes of the limb
bones. Homologous bones are the same color in all
the drawings.
Monkey
Horse
Mole
Bat
Seal