GIT control Flashcards
What is an Endocrine hormone?
Picked up by blood vascular system & transported out of gut (acting as a classical hormone)
What is a Paracrine hormone?
Diffuses through extracellular fluid to local or neighbouring target cells
What is an Autocrine hormone?
Released into extracellular environment but feeds back on its cell of origin ie. target cell & secreting cell are the same
What is a Neurocrine hormone?
Released by the enteric NS (varicosities), secreted in response to action potentials to affect nearby muscles & glands.
2 major enteric plexuses embedded in the wall of the GIT
Submucosal and myenteric..
What does leptin do? what does it act on?
suppresses hunger, Hypothalamus
where is leptin released from?
Adipose cells release it when long-term energy intake exceeds demands
what is Grehlin?
a hormone that stimulates appetite
where is Grehlin released from?
gastric cells when stomach is emptying
what do PYY and Grehlin work together to control?
Both Grehlin & PYY seem to be important in controlling “desire” to eat.
what does Peptide YY (PYY) do? where is it released from?
Reduces appetite
Released from enteroendocrine cells when colon is full
what is short term regulation in relation to appetite?
balances HUNGER vs SATIETY
satiety factors…
Insulin
CCK
Neural input from chemo- & mechano- receptors in GIT wall
What is CCK?
Cholecystokinin
2 key functions of immune cells:
Create antigenic memory, so can synthesise antibodies
Secrete inflammatory mediators (prostaglandins, histamine & cytokines)
