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