also called coelenterates

-characterized by stinging cells

-jellyfish

-anemomnes

-coral

-hydras

flat worms

snails

slugs

oysters

clams

squids

octopi

segmented worms

-earthworms

Arthropoda

(crustaceans) i.e. 

-crabs

-lobsters

-shrimp

(insect arachnids) i.e.

scorpions, ticks, mites, spiders

sea stars / brittle stars

sea urchins

sea cucumbers

everything else

humans, frogs, donkeys, monkeys, etc...

only one opening

-feces goes out same hole food goes in

-hydra

-platyhelminthes

-two openings, mouth and anus

-regional specialization

-some animals have specialized compartment for food storage

-higher on evolutionary tree

-increased SA of absorption area

-less waste 

part of gut for mechanical degradation, protein digestion, lipid digestion, carb digestion, absorption

-essentially, has different parts to its digestive tract and these different parts have different fxns

-have stinging cells

-DO ALL HAVE INCOMPLETE DIGESTION?

-incomplete digestive tract

-stings prey with nematocysts on tentacles

-brings to mouth and enters GV cavity

-enzymes secreted by gastrodermis (extracellular), but most digestion is intracellular

-needs extracel dig. to get stuff small enough for intracellular dig.

about hydra

-2 layers of cells, epidermis, gastrodermis

-food goes from mouth to GV cavity

-folds in GV cavity maximize SA/vol ratio

-

-incomplete digestive tract

-pharynx (on its underside (belly area) sucks up food and expells waste)

-extracellular then intracellular

-mouth - where pharynx joins GV cavity

complete digestive tract

all extracel. dig.

-mouth - takes in soil/decaying material

-pharynx sucks food in , has mucous, enzymes

-esophagus - just a tube that connects pharynx to crop

-crop - stores food before it enters gizzard

-intestines - after gizzard, enzymes digestion, absorption, water reabsorption

-mechanical breakdown (chewing)

-lubrication, begin enzymatic digestion (salivary glands)

-microbicide (kills microbes)

taste and smell

-(only right half)

-2 incisors (biting, chisel-shaped)

-1 canine (for tearing MEAT, sharp, pointed)

-2 premolars

-3 molars (flattened for grinding and crushing)

mammals are heterodont (many types of teeth)

some vertebrates are homodont (only one type of tooth)

-carnivores: large canines, all teeth pointed for tearing meat

-herbivores: broad flat teeth for grinding cell walls

-rodents: extremely long incisors for gnawing)

-incisors will grow forever if the don't gnaw on stuff

-sublingual gland

-submaxillary gland

-parotid gland

release saliva with digestive enzymes

pharynx

muscular tube, keeps respiratory and digestive passageways separate

-this is what the epiglotis closes over when you swallow

peristalsis

muscular contraction that pushes bolus of food ahead of it

muscle between stomach and esophagus

-normally is closed, opens when bolus reaches it

stomach:

responsible for:

large muscluar sac

-storage

-mixing chyme

-mechanical and chemical (HCl and pepsin) breakdown of food

folds on inside of stomach to increase SA

-within this there are gastric glands

through pyloric sphincter to small intestines

inside rugae

-contain parietal cells which secrete HCl (lowers pH kills bacteria)

-contain chief cells which secrete pepsin (requires low pH (thats why theres HCl), and denatures proteins)

overproduction of gastric acid can eat a hole in the stomach wall, mucosa makes this a rare occurence

-most "stomach" ulcers are actually duodenal

Digestive system of vertebrates: Small intestine

-duodenum, jejunum, ileum

-enzymatic digestion, mixing, absorption of nutrients

-long, coiled, has ridges and folds

-ridges covered with villi (finger like projections)

-villi covered with microvilli

-increases SA mucho

Digestive system of vertebrates: Accessory structures associated with small intestine:

Pancreas

secretes enzymes (trypsin, chymotripsin, amylase, lipase) to digest protein, starch and fat

Digestive system of vertebrates: Accessory structures assocoiated with the small intestine

Liver

Digestive system of vertebrates: Accessory structures assocoiated with the small intestine

Gall Bladder

facilitates fat digestion

-breaks down fat droplets into smaller ones

Digestive system of vertebrates: Large Intestine

absorbs water and electrolytes from c hyme

-forms and stores feces

-in herbivores,  contains lots of microorganisms

- helps herbivores diegest cellulose but not very efective because still poop out lots of plant material

-vestigial structure in humans

-we can't digest cellulos

In Herbivores, fermentation chamber for digestion of cellulose

-mammals can't digest cellulose, some bacteria can (symbionts)

-in rumanants (like cows), bacteria live in rumen and reticulum, 2 of the 4 "stomachs"

chyme from rumen is regurgitated and chewed some more then returned to omasum

2 of the 4 stomachs in ruminants

-bacteria breake down cellulose, give ruminant glucose

-bacteria are housed in these parts of the stomach and feed on the cellulose

Digestive System of Vertebrates: Adaptations of small inestine according to diet

longer small intestine in herbivores than omnivores and carnivores because harder to digest plant material than animal material

-carnivore small intestine is straight

-herbivore small intestine is coiled  

Digestive System of Vertebrates: Herbivore adaptations in the large intestines (cecum)

rabbits

rabbits have two types of feces

-one is material from cecum, which they reingest (poop out and eat again)

-other type is waste (so I guess it bypasses the cecum this time) that they don't eat

differences in digestive system in mammals:          1) insectivore

2) non-ruminant herbivore

3) ruminant herbivore

4) carnivore

1) i.e. rat, simple stomach short intestine, NO CECUM

2) i.e. rabbit, simple stomach, large cecum

3) i.e. deer, 4-chambered stomach with large rumen, long small and large intestine, has cecum

4) i.e. wolf, short intestine and colon, small cecum