Gastrointestinal system – autonomic control and splanchnic circulation Flashcards
autonomic control - PNS 1
originates from
- vagus nerve = upper GI
- pelvic splanic nerves = lower GI
autonomic control - PNS 2
ACTIVATION
activated when smelling/ thinking/ seeing food
- signals sent to salivary glands in pons/ medulla
- signals sent to facial nerve + glossopharyngeal nerve
- Ach released to bind to M receptors
autonomic control - PNS 3
motility
- increased by peristalsis + smooth muscle contraction
autonomic control - PNS 4
SECRETION
- pancreas = digestive enzymes
- stomach = gastric acids
- liver = bile
autonomic control - PNS 5
SPHINCTER
- relaxation of osephageal / pyloric sphincters
- allowing passage of foods
autonomic control - PNS 6
BLOOD FLOW
- more blood flow to GI system
- helps absorb/ digest nutrients
autonomic control - SNS 1
originates from T2-L5 spinal nerves
autonomic control - SNS 2
ACTIVATION
- activated when noradrenaline binds to B adrenergic receptors
- activating fight or flight response
autonomic control - SNS 3
motility
- less smooth muscle contraction
- less peristalsis
autonomic control - SNS 4
SECRETION
= inhibited
autonomic control - SNS 5
SPHINCTERS
- osephageal + pyloric sphincters contract
- forcing them closed to prevent passage of food
autonomic control - SNS 6
BLOOD FLOW
- blood flow reduced to GI tract
autonomic control - ENS 1
myenteric auerbach plexus
- located between longitudinal + circular muscle layer = increasing motility
autonomic control - ENS 2
submucosal meissner plexus
- located in tunica submucosa
- increasing nutrient absorption/ secretion
splanchnic circulation - 1
a. mesenterica superior = small intestine + upper colon
