GI 8

Question 1

short term regulation

Answer 1

short term all depends on the last time you ate food (compliments long term regulation)
also acting on arculate nuclueus

you body tries to balance satiety signals that are generated from digestion and orexigenic signals that are generated during fasting

Question 2

Ghrelin

Answer 2

stimulus: releases when less distension in the stomach (empty)

response: stimulates NPY/AGRP in the arcuate nucleus

injecting Ghrelin will make you more hungry unless you dont have NYP/ARGP

Question 3

gastric distension

Answer 3

stimulus: full stomach (distension of stomach)

response: sends info to NTS which has connection to PVN and ARC

injecting it would make you less hungry

Question 4

CCK

Answer 4

stimulus: full stomach (distension of stomach)

response: sends info to NTS which has connection to PVN and ARC

released by I cells in duodenum in response to fats and amino acids entering the small intestine

injecting it would make you less hungry

Question 5

insulin/glucose

Answer 5

during cephalic and gastric phase increaes insulin which causes a drop in glucose which drives hunger though activation of NPY/AgRP neurons

during intestinal phase, inceased glucose and insulin makes you feel satieted through activation of aMSH/CART neurons in the arcuate nucleus

Question 6

marijuana and the munchies

Answer 6

stimuatles appetite

-given to ppl with chronic diseases associated with reduced appetite

-reseach on mice points to an enhanced sense of smell

-weed activates activation of the NPY/AgRP neurons in ARC - CB1 receptors in LH

Question 7

Energy output %

Answer 7

50% energy lost in heat

50% energy used for work
-transporting across membranes
-mechanical work (e.g muscle contractions)
-chemical work (growth and maintenance)

Question 8

how do we measure energy input and output

Answer 8

Bomb Calorimeter
-measured in kilocalories
-heat released from burned food is measured
-slightly overestimated cuz we dont fully digest everything

Dietary calorimeter is more accurate

Indierect caloriemeter (measures o2 consuption or co2 production) is the easiest way

Question 9

energy output calculatation

Answer 9

energy output = work + heat

Question 10

Basal Metabolic Rate (BMR)

Answer 10

resting amount of energy used just to stay alive

lowest metabolic rate = when sleeping

depends on age and sex and lean muscle mass, and hormones and genetics

Question 11

What is metabolism

Answer 11

refers to all of the life sustaining chemical reactions that occur (3 catagories)

1. extract energy from nutrients
2. use energy for work (transport)
3. stores excess energy for later use

fed state is mainly anabolic = turning small molecules into bigger ones for storage or whatever

Question 12

fed state

Answer 12

skeletal muscle:
-takes up glucoes for energy use and stores a glycogen (70% of body storage)

Liver:
-converts glucose into glycogen (24% of body storage) and
-converts glucose into fatty acids (transported to adipocytes)
-AA’s are used for sythesis and converted to keto acids (energy or fatty acid synthesis

adipocytes:
-take up dietary triglycerides from chylomicrons
-excess glucose taken up and converted to triglycerides
-stores triglycerides sythesized in liver

FAT STORAGE = unlimited
GLYCOGEN AND PROTIEN STORAGE: limited

Question 13

fasted state

Answer 13

in between meals Catabolism takes place to utilize stored energy

Question 14

energy storage

Answer 14

glycogen: storage can sustain quiet activity for only a few hours

proteins: potentailly for long periods of time but decreased protein levels eventually compromise cellular function

Fats: for approximatly two months

Question 15

beta-cells

Answer 15

when glucose is high it burns it - this causes depolarization in the cell

Question 16

tyrosine kinase receptor

Answer 16

-causes insertions of glucose transporters
-increase or decrease metabolic enzyme activity

(most other ones are g-coupled protien receeptors)