Anatomy of the GI tract

Question 1

What is hunger/satiety regulated by

Answer 1

• plasma glucose leveles
• hormones
  
  • leptin
  • grelin
  • insulin
  • glucagon
• stretch receptors in GI tract
• stress, body temperature food palatibility

combination of hormonal, neuronal, and mechanical signals

Question 2

ghrelin

Answer 2

hunger hormone

Question 3

leptin

Answer 3

full hormone

Question 4

well fed/post-absorptive state

Answer 4

• increase in glucose, fat, protein
• increase in storage of fuels and protein synthesis
• glycogen synthesis
• insulin secretion
• increase in leptin

Question 5

what happens in the fasting state

Answer 5

• decrease in glucose, fat protein
• increase in
  
  • glucagon - glycogen breakdown
  • gluconeogenesis - creation of new glucose
  • glucose sparing - fat utilisation, lipolysis
• increase in grehlin

Question 6

appetite centre in brain

Answer 6

• lateral hypothalmus

Question 7

what is the satiety centre

Answer 7

• medial hypothalmus

Question 8

what is the effect of meal size on gastric emptying

Answer 8

• different meal components empty at different rate
• more food = longer digestive phase
• larger amount of food empty slowly to begin with, then more quickly
• nutrition density (calories) controls / slow gastric emptying

Question 9

What is the effect of fat content?

Answer 9

• important delaying factor in gastric emptying
• fat in the duodenum causes fundus to relax, lowering intragastric pressure
• high fat meal increases feeling of fullness for longer than a low fat meal of the same energy content
• influences intake at new meal
• prolongs the elevation of pH in the stomach

Question 10

fundus of stomach

Answer 10

• upper part of the stomach, which forms a bulge above the level of the opening of the oesophagus

Question 11

HOw does food intake affect absorbtion of enteric coated erythromycin pellets

Answer 11

• different drugs & formulation affected differently by presence of foods
• food can affect drug absorbtion