Regulation and Energy Balance

Question 1

Weight is controlled by the

Answer 1

hypothalamus

Question 2

Weight is modulated by

Answer 2

pleasure NTs:

• opioids
• dopamine
• endocannabinoids

Question 3

Which NTs cause you to eat?

Answer 3

Arcuate nucleus:

• neuropeptide Y
• AGRP

Lateral hypothalamus

• orexin
• MCH

Question 4

Which NTs inhibit food intake?

Answer 4

Arcuate nucleus:

• aplha-melanocyte stimulating hormone (aMSH)
  
  • via melanocortin receptor 4
• cocaine and amphetamine receptor transcript (CART)

Paraventricular hypothalmic nucleus

• oxytocin
• CRH

Question 5

How is food intake controlled?

Answer 5

• vagus nerves project to brainstem
• brainstem projects to paraventricular hypothalmic nucleus and lateral hypothalamus
• these structures receive input from the arcuate nucleus:
  
  • CART and aMSH stimulate the PVH to release oxytocin and CRH to decrease food intake via the brainstem and vagus
  • NPY and AGRP stimulate the LH to release orexin and MCH to increase food intake via the brainstem and vagus
• modulated by pleasure NTs: opioids, dopamine, endocannabinoids

Question 6

The brain responds to which peripheral signals of nutritional state?

Answer 6

• leptin
• insulin
• nutrients

Question 7

leptin

Answer 7

• made in fat cells proportionally to cell size
  
  • bigger cells, more leptin
• travels to brain via bloodstream
• taken up by its receptor
• signals size of fat stores
  
  • high leptin = high fat stores
  • low leptin = eat more

Question 8

insulin

Answer 8

• long-term signal to brain of fat stores
  
  • higher stores = decrease food intake
• suppresses glucose production in the liver
  
  • metabolism of glucose causes increase of LCFA-CoA which inhibits food intake; tf decreased metabolsim = increased food intake
• tf in brain, inhibits food intake; in liver, increases food intake​

Question 9

endocrine causes of weight loss

Answer 9

• untreated type I diabetes mellitus
• thyroxtoxicosis
• addison’s disease (cortisol lack)

Question 10

GI causes of weight loss

Answer 10

• chronic pancreatitis
• cystic fibrosis
• inflammatory bowel disease
• parasitic infection

Question 11

infective causes of weight loss

Answer 11

• TB
• subacute bacterial endocarditis
• amoebic abscess
• HIV