UNIT 6b Flashcards
STUDY
GI function regulation has what reflexes?
- long (integrated in brain)
- short (integrated in gut) –> called gut bain sometimes
long reflexes characteristics
- sensory info from GI
- feedforward reflexes: sight, smell, thought of food, emotion can cause us to stimulate our GI tract
- efferent always autonomic: increase parasympathetic (excitatory) and decrease sympathetic (inhibitory)
- dont need to have anything in GI tract
goal: increase secretion increase motility
small reflexes characteristics
- integrated within gut
- enteric nervous system (gut brain)
- submucosal plexus receive signals from lumen, regulate secretion
- motility regulated by neurons in myenteric plexus
- have to have something in your GI tract
parallels between enteric system and CNS
ENTERIC SYSTEM:
- has intrinsic neurons
- release neurotransmitters and neuromodulators
- integrating centre
- has glial support cells
- BBB similarity called a difussion barrier but acts exactly same as BBB (blood brain barrier)
GUT PEPTIDES ARE MAJOR ________ PLAYERS
REGULATOR PLAYERS
GUT PEPTIDES ARE PRODUCED BY?
cells within the lamina propria
travel of peptides
can travel paracrine or endocrine (blood)
effects of gut peptides:
- effects motility (altered peristalsis, gastric emptying)
- effects endocrine & exocrine secretion
- some peptides act on brain
can gut peptides also be called hormones?
yes, they travel endocrine via the blood
GUT peptide endocrine pancreas goals
increase inulin
decrease glucagon
GUT peptide endocrine brain goals
hunger
satiety
the Duodenum is the beginning of what?
small intestine
how did the pancreas know there was an increase in stomach acid as it hits duodenum based on pavlov?
pancreas secretion was thought to be controlled by vagus nerve, he says that this was ALL NEURAL
how did the pancreas know there was an increase in stomach acid as it hits duodenum based on Bayliss and starling?
- dissected the nerves
- put acid in duodenum
- pancreas secreted bicarb still
so it NOT neural
hypothesis: blood born signal
what are the gut hormones
- Gastrin family
- Secretin family
- Motilin
swallowing reflex
- tongue pushes food (bolus) against soft plate and back of mouth triggering swallow reflex
- breathing inhibited as bolus passes
- food moves downward into esophagus and propelled by peristaltic waves
swallowing reflex is integrated in medulla, cranial nerves mediate reflex
regulation of cephalic stage
- brain perceives food, smell, visually etc
- coordinated in medulla
- travels in vagus nerve
- gets to taregt cells
- secretion and motility
regulation gastric phases
- food reaches stomach
2 stretching detects peptides and amino acids need digesting
3 digestion occurs
are local and occur in the stomach
- short reflexes
what are the three functions of the stomach and describe them?
- storage:
- receives food and relaxes w/out storage problem can arise (gastric dumping syndrome) - digestion:
- most important, break down molecules into chyme, secretion of enzymes, acid and hormones. - protection:
- protects itself from acid and antimicrobial acid
IMPORTANT SLIDE SECRETORY CELLS OF GASTRIC MUCOSA
IMPORTANT SLIDE SECRETORY CELLS OF GASTRIC MUCOSA
Parietal cells make?
H+
chief cells make? w/ H+ present
pepsin