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Flashcards in Gastrointestinal Deck (191)
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1

Epthelial cells are specialied in different part of the GI tract for ________or _________

secretion or absorption

2

Contraction causes a change in the surface area for secretion or absorption

Muscularis mucosa

3

Contraction causes a decrease in diameter of the lumen of the GI tract

Circular muscle

4

 Contracion causes shortening of a segment of the GI tract

Longitudinal muscle

5

Comprise the enteric nervous system of the GI tract

Integrate and coordinate the motility, secretory, and endocrine funcrions of the GI tract

Sumbmucoasl (meissner plexus) and myenteric plexus

6

the _____________of the GI tract comorises both extrinsic and intrinsic nervous systems

ANS

7

Extrinsic innervation

PNS and SNS

8

carry information from the brain ste and spinal cord to the GI tract

Efferent fibers

9

Carry sensory information from chemoreceptors and mechanoreceptors in the GI tract to the brain stem and spinal cord

Afferent fibers

10

_______________is usually excitatory on the functions of the GI tract

Parasympathetic

  • carried via the vagus and pelvic nerves
  • Preganglionic PS fibers synapse in the yenteric and submucosal plexus
  • cell bodies in the ganglia of the plexuses then send information to the smooth muscle, secretory cells, and endocrine cells of the GI tract

11

The _______ innervates the esophagus, stomach, pancreas, and upper large intestine

Vagus nerves

  • Reflexes in which both afferent and efferent pathways are contained in the vagus nerve are called vasovagal reflexes

12

the _____ innervates the lower large intestine, rectum, and anus

Pelvic nerve

13

___________ is usually inhibitory on the functions of the GI tract.

Sympathetic nervous system

  • Fibers originate in the spinal cord  between T8 - L2
  • Preganglionoc sympathetic cholinergic fibers synapse in the prevertebral ganglia
  • Postganglionic sympathetic adrenergic fibers leave the prevertebral gangla and synapse in the myenteric and submucosal plexues. Direct postganglionic adrenergic innervation of blood vessels and some smooth muscle cells also occurs
  • Cell bodies in th eganlia of the plexuses then send information to the smooth muscle, secretory cells and endorcrine cells of the GI tract

14

Coordinates and relays information from the PNS and SNS to the GI tract

Intrinsic nervous system (enteric nervous system)

  • uses local reflexes to relay within the GI tract
  • controls most functions of the GI tract, especially motility and secretion, even in the absence of extrinsic innervation

15

Primarily controls the motility of the GI smooth muscle

Myenteric plexus (Auerbach plexus)

16

Primarily controls secretion and blood flow

Receives sensory information and chemoreceptors and mehanoreceptors in the GI tract

Submucosal Plexus (Meissner plexus)

17

"official" GI hormones

gastrin

cholestokinin

seccretin

glucose insulinotropic eptide (GIP)

18

Increases H+ secretion. Stimulates growth of gastric mucosa

gastrin

  • Stimulus:
    • small peptides and amino acids
    • distention of stomach
    • vagus (via GRP)
    • inhibited by H+ in stomach
    • Inhibited by somatostatin
  • Gastrin -CCK family

19

Stimulates cobtraction of gallbladder and relaxation of sphincter of Oddi. 

Increase pancreatic enzyme and HCO3 secretion

Increase growth of exocrine pancreas/gallbladder

Inhibits gastric emptying

CCK

  • Stimulus
    • small peptides and amino acids
    • fatty acids
  • gastrin-CCK family

20

Increase pancreatic HCO3 secretion

Increase Biliary HCO3 secretion

Decrease gastric H+ secretion

Secretin

  • Stimulus
    • H+ in duodenum
    • Fatty acids in the duodenum
  • Secretin-glucagon family

21

Increase insulin secretion

Decrease gastric H+ secretion

GIP

  • Stimulus
    • fatty acids, amino acids, and oral glucose
  • secretin-glucagon family

22

Site of secretion of gastrin

G cells of the stomach

23

Site of secretion of CCK

I cells of duodenum and jejunum

 

24

Site of secretion of Secretin

S cells of duodenum

25

Site of secretion of GIP

Duodenum and jejunum

26

little gastrin have _______ amino acids

Big gastrin have _________- ammino acids

17

34

27

All biologic activity of gastrin resides in the____________

four C-terminal amino acids

28

Gastrin inncreases H secretion by gastric ___________ cells

parietal

29

Paatients with ________ have hypertrophy and hyperplasia of the gastric mucosa

gastrin secreting tumors

30

The most potent stimuli for gastrin secretion are _______ and ________

Phenylalanine and tryptophan