Metabolism: Control of Food Intake

Question 1

Site of Feeding center

Answer 1

Lateral nucleus of Hypothalamus

Question 2

Site of Satiety center

Answer 2

Vetromedial nucleus of Hypothalamus

Question 3

Destruction (lesion) to feeding center leads to

Answer 3

Fatal anorexia/ Marked weight loss

Question 4

Destruction (lesion) to Satiety center leads to

Answer 4

Polyphagia & Obesity

Question 5

2 Types of Neurones located in Arcuate nuclei

Answer 5

• Pro-opi-melano-cortin (POMC) Neurones
• NPY-AGRP Neurones

Question 6

Role of POMC Neurones

Answer 6

Secretes Anorexigenic Substances which decrease appetite & food Intake

Question 7

Role of NPY-AGRP Neurones

Answer 7

Secretes orexigenic substances which increases appetite & food intake

Question 8

Anorexigenic Substances secreted by POMC Neurones

Answer 8

• CART
• CRH (cortico-tropin releasing hormone)
• Alpha Melanocyte- Stimulating hormone

Question 9

Orexigenic Substances released from NPY-AGRP Neurones

Answer 9

• Neuropeptide Y (NPY)
• Agouti Related protein (AGRP)

Question 10

Enumerate short term regulating factors of Food intake

Answer 10

1. Gastrointestinal filling & distension: sends inhibitory signal by vagus nerve to supress feeding center
2. Oral factors: Chewing, swallowing, salivation
3. Gut Theory: Via GIT hormones

Question 11

GIT hormones Inhibiting feeding center

Answer 11

• CCK (cholecystokinin)
• PPY (polypeptide Y)
• GLP (Glucose-like peptide)

Question 12

GIT hormones that Stimulate feeding Center

Answer 12

Ghrelin

Question 13

Enumerate Intermediate and Long term regulation

Answer 13

• Glucostatic Theory
• Lipostatic Theory
• Thermostatic Theory

Question 14

Describe Glucostatic Theory

Answer 14

Rise in Glucose level increases glucose utilization, so:
* Inhibits feeding center
* Stimulates Satiety Center

Question 15

Describe Lipostatic Theory/ Function Leptin

Answer 15

1. Leptin secreted from Adipocytes during excess energy stores
2. It crosses Blood brain Barrier
3. Reaches its receptors on POMC in hypothalamus
4. This causes Decrease of Fat storage by:
   * Inhibiting NPY & AGRP, Decreasing appetite
   * activates POMC to release Alpha melanocyte stimulating hormone, decreasing appetite
   * Increase CRH release, decreasing appetite
   * It increases Sympathetic Activity & metabolic rate

Question 16

Describe what happens to food intake during exposure to cold

Answer 16

Increases food intake, due to:
* Increase in Metabolic rate to increase in heat production
* Increase fat for insulation

Question 17

Definition of Anorexia

Answer 17

reduction in food intake

Question 18

Definition of Cachexia

Answer 18

metabolic disorder caused by increased energy expensure leading to marked weight loss

Question 19

Causes of Anorexia-Cachexia disorder

Answer 19

Cancer or AIDs, by:
* Inflammatory cytokines which activates POMC system