GIT - Lecture 2 Flashcards
Endocrine secretions move into the…
blood
Exocrine secretions move into the…
lumen of the gut
ANS – “modulates” ENS activity via
LONG, EXTRINSIC REFLEXES
ENS regulates GIT via
ANS – “modulates” ENS activity via LONG, EXTRINSIC REFLEXES – synaptic connections with ENS neuronsSHORT, INTRAMURAL REFLEXES
What causes activation of the ANS?
signals at the level of the gut that send sensory afferents to the CNS
What is the pathway of long extrinsic reflexes?
- chemoreceptors, osmoreceptors, mechanoreceptors
- afferent neurons
- central nervous system
- efferent autonomic neurons (S or PS)
- nerve plexus
Where do efferent autonomic neurons synapse?
nerve plexus
Where do long extrinsic reflexes happen?
outside the gut wall
What are 2 direct ways we can activate the ANS?
- sight, smell, taste of food
- emotional state
The ___ modulates the activity of the ENS.
ANS
Parasympathetic is ___, whereas sympathetic is ___.
excitatory, inhibitory
Parasympathetic may also ___ inhibitory neurons.
excite
Sympathetic may also ___ inhibitory neurons.
inhibit
The activities of the GIT are integrated for high functional efficiency by which 2 mechanisms?
neural and hormonal mechanisms
What do non-GIT hormones influence?
growth and development of GIT
What do GIT hormones influence?
activities outside the GIT
What is released by glands in the stomach during fasting?
ghrelin
What does ghrelin activate?
hypothalamic “feeding centre”
What does ghrelin stimulate?
hunger and increases apetite
What is released by fat cells with overeating?
leptin
What does leptin activate?
hypothalamic “feeding centre”
What does leptin induce?
satiety and decreases apetite
What is DES?
diffuse endocrine system
Where is the DES scattered?
among cells in the mucosa
What is the largest, most diverse endocrine system in the body?
DES
What are the 5 important GI hormones?
- gastrin
- CCK
- secretin
- GIP
- VIP
What are the 3 different modes of hormone regulation?
autocrine, paracrine and endocrine effects
What is the autocrine effect?
the hormone released by an endocrine cells have effects on cells that release that hormone
What is the paracrine effect?
the hormone released by paracrine cells have effects on nearby cell
What is the endocrine effect?
the hormone released by the endocrine cells move through the capillary and have effects on target tissues