GI tract pt1 Flashcards
What are regulated functions of the GI system?
- Motility
- Secretion
- Digestion
- Absorption
- Storage/elimination
Fermentative digestion relies on what?
Symbiotic microbes
What innervates the GI?
- Sympathetic
- Parasympathetic
- Enteric
What intrinsic systems regulate the GI?
- Hormonal
- Immune control
- Trophic effects
- Enteric nervous system
What extrinsic systems regulate the GI?
- Nerves (PS and S)
- Extrinsic hormonal (aldosterone)
ENS receives input from?
PS and S
What does the submucosal plexus do?
(Meissner’s) located in submucosal layer and deals with secretions and local blood flow
What does the myenteric plexus do?
Regulate muscle contraction and motility. Between circular and longitudinal muscle layers
How do ENS neurons differ from normal neurons?
They have collaterals and varicosities
What cells detect nutrients and chemicals in the GI?
Enteroendocrine cells
What happens when enteroendocrine cells detect nutrients or chemicals?
It is detected by GPCR in the lumen with then releases regulatory peptides into the interstitium and synapses with the ENS which will change the blood flow and secretion
What detects stretch in the GI?
Mechanoreceptors in the muscles layers which then activate the myenteric plexus
What are the type of neurons in the ENS?
- Excitatory (Ach and substance P)
- Inhibitory (NO and VIP)
What is the parasympathetic components of the GI?
- Vagus
- Pelvic nerve
- Preganglionic
- Stimulatory
- Acetylcholine (cholinergic)
What is the sympathetic components of the GI?
- Splanchnic nerve
- Postganglionic
- Inhibitory
- Norepinephrine
