GI 7

Question 1

defecation

Answer 1

short and long reflexs

short: local peristaltic contractions

long: stimulates parasympathetic in sacral spinal cord (increases peristaltic contrations too)

BOTH are stimulated by distentsion of the large intestine and push fecal matter down sigmoidal region of the rectum

Question 2

what is diarrhea

Answer 2

increasesed frequency of volume and fluid on feces, reduced absorbtion and increased motility

types: osmotic, secretory, inflamatory, motility induced

Question 3

clostridium difficie infections

Answer 3

caused by penicillin antibiotics which alter the normal bacterial flora

kills the good bacteria and leaves room for the bad ones

causes Colitis (inflammation of the colon): watery diarrhea, fever, nausea

SOLUTION: fecal transplant colonoscopy

Question 4

vomiting

Answer 4

forceful expelling through the mouth

Medulla: vomiting center (stops contractions - food reverses the other way)(relaxes esophagus sphincters)
chemoreceptor trigger zone

causes:
motion sickness (chemo trigger zone)
input from stomach repectors (vomit center)
toxins: (chemo trigger zone)

Question 5

immune function of the GI tract

Answer 5

gut-associated-lymphoid-tissue (GALT)

M-cells play a big role in immune responses: sample lumen contents
-receptor mediated endocytosis
-release cytokines

Question 6

GI doesnt regulate intake so we rely on behavioural mechanisms

what happens during the feeding state

Answer 6

glucose converted to glucogen whihch can be stored in different ways

Question 7

GI doesnt regulate intake so we rely on behavioural mechanisms

what happens during the fasting state

Answer 7

uses the stored energy from the feeding state

Question 8

what happens if the lateral hypothalus is damaged

Answer 8

youll get skinny and lose motivation for hunger (leteral hypothalamic syndrom)

Question 9

what happens if the lateral hypothalus is stimulated

Answer 9

youll get hungry

Question 10

what happens if the ventromedial hypothalamic center is damaged

Answer 10

you will eat and never feel satisfied

Question 11

what happens if the ventromedial hypothalamic center is stimulated

Answer 11

would stop eating and feel satiated

Question 12

what are the 3 real reasons that drive hunger and statiety

Answer 12

ARC - acuate nucleus
PVN paraventricular nucleus
LH - lateral hypothalamus

Question 13

long term & short term regulators

Answer 13

glucostatic theory: glucose availability goes down make you hunger (SHORT)

lipostatic theory: signals from fat storage regulates hunger (LONG)

Question 14

ob/ob gene

Answer 14

hormone called leptin produced when we have excess fat/lipids

thought it was cure to fatness
but fat ppl can have it but the brain doesnt respond to it

Question 15

what happens with excessive leptin?

Answer 15

arcuate nucleus…

-inhibits lateral feeding center
-activates PVN (increases energy output)
happens through humoral respose which increases TSH and ACTH from pituitary
alos happens through Visceromotor respose which increases sympathetic (body temp)

Question 16

what happens with low leptin levels?

Answer 16

reduced activation of a-MSH and CART neurons
-reduced PVN activation which lowers TSH and ACTH which decreases metabolism
-activates NPY and AgRP neurons which stimulates feeding center and inhibits PVN