Digestive system Flashcards
types of feeding methods
filter/suspension feeders detritivores (deposit feeders) fluid feeders carnivores herbivores omnivores symbiotic-autotroph bearers (carry other organisms but produce nutrients for them)
size and filter/suspension feeders
e. g. whales/crinoid
v. big or v.small
example of a symbiotic-autotroph bearer
tube worm
two mechanism which link functions of digestive tract with outside world
hunger mechanism
thirst mechanism
Hunger mechanism hormones
grelin - feel hungry (produced by stomach)
leptin - feel satiated (produced by adipose cells)
leptin resistance
leads to obesity
no longer feel hungry
order of choice of source of energy in body (human)
- carbohydrate
- fats
- protein
why does energy production decrease with different sources of energy than carbohydrate?
fats (glycerol & fatty acids) and proteins (amino acids) come in on cycle later on than with carbohydrate and therefore potential ATP production from missed steps is lost
types of extracellular digestion (evolution)
- gastrovascular cavity
2. set of complete tubes
motility - muscles
smooth muscle under autonomic control BOTH tonic (low tone contraction) and phasic (periodical contractions triggered)
general aspects of digestion
motility
secretion
digestion
absorption
control of digestive system
Autonomous smooth muscle Local sensory receptors Intrinsic nerves Extrinsic nerves (sympathetic & parasympathetic) GIT hormones
4 basic layers of tissue in digestive tract
outermost layer - seroza
conducting & contracting - smooth muscle layer +enteric nervous system
connective - submucosa
covering (epithelial tissue) - mucosa
lumen
enteric nervous system
almost a completely separate nervous system with digestive system
glands in the digestive tract
liver
pancreas
salivary
what is the mucosa layer made up of?
- epithelium
- lamina propria (lymphoid tissue & mucus producing glands
- muscularis mucosi (first layer of folding)
what is the mucosa layer made up of?
- epithelium
- lamina propria (lymphoid tissue & mucus producing glands
- muscularis mucosi (first layer of folding) - capillaries and ends of lymphatic system
what does the seroza do?
full support of digestive tract - keeps it in place (epithelium + connective)
what does the submucosa constain?
glands & blood vessels - arterioles and venuoles
what does the mucosa do?
secrete some of digestive enzymes (hold in brush border - microvilli)
interesting difference with snail
radula - grind food with mouth & suck in
spiral valves - where found & what do?
sharks
short digestive tract - used to slow passage of food
cloaca as oppose to anus
combined urinary and digestive tract exit
crop - what is it? & who has it?
gravel in it (birds), grind, pre-stomach
found in birds & insects
mouthpart types - invertebrate
sponge (and suck) - e.g. flies
proboscis - suck up food - e.g. butterflies
mandibles - e.g. tiger beetle
how to insects intially taken up food?
sucking
mouthparts - vertebrate adaptations
chizel-like teeth - rodents
fangs - venom channel in tooth
sharks - many rows of teeth
cats& dogs drink by lapping
what is different about herbivores teeth?
teeth keep growing
insect midgut
mesenteron
what is the peritrophic (matrix) membrane?
Insect midgut
internal body-organ tissue
made of chitin
floats above aborption layer
carries enzymes
ruminant stomach
abommasum - similar to stomach in humans
names of four chambers in ruminant midgut
rumen
reticulum
omasum
abomasum
limitation to ruminant digestion environments
fibrous material can slow down digestion and lead to starvation
birds digestion order
glandular stomach - enzymes secreted
gizzard - grit & grinding
caecum with diet
smaller if eat more meat (carnivorous)
where is the fat body found?
insects - storage organ/lymphatic system/endocrine system/immune/excretion
what is a hepatopancreas?
does same job as liver and pancreas but one organ
- arthropods, molluscs, fish
