Regulation Of Food Intake Physiology Flashcards
What are the hypothalamic nuclei that are important for controlling feeding?
Paraventricular nuclei
Arcuate nuclei
also hypothalamus, lateral hypothalamic area and third ventricles , but these are not a nuclei
Stimulation of the lateral hypothalamic nuclei causes what?
Increased feeding sensation
- lesions = decreased feeding
lateral hypothalamic syndrome = lesion to the lateral hypothalamic nuclei leads to extreme anorexia
Stimulation of the ventromedial hypothalamic nuclei causes what?
Decreased feeding
- lesions causes increased feeding impulses
ventromedial syndrome = lesion to ventromedial nuclei = gets obese real quick
Stimulation of the dorsomedial hypothalamic nuclei causes what?
Increased rage
- lesions cause decrease rage and feeding sensations
Stimulation of the paraventricular hypothalamic nuclei causes what?
Increased blood volume/pressure and metabolism
- lesions = diabetes insipidous
What do pro-opiomelanocortin (POMC) neurons do?
Function to release (a)-melanocyte-stimulating hormone (a-MSH) and CART transcripts that ultimately results in decreasing food intake and increasing energy expenditure
What do neurons that product agouti-related proteins (AGRP) and neuropeptide Y (NPY)?
Increasing food intake and reducing energy expenditure
Leptin vs ghrelin
Leptin:
- produced by fat cells and enteroendocrine cells of the stomach
- decreased NPY/AgRP pathways and increases POMC neuron action
- *effects = decrease appetite/increase metabolism/decrease ghrelin release
Ghrelin:
- produced by enteroendocrine cells of the stomach/intestines
- increases NPY and AgRP pathways
- effects = increase appetite, decrease metabolism, decrease leptin release
Ghrelin specifics
Located in PD/1 cells in stomach glands
Targets lateral hypothalamic brain cells And stomach cells
Action is to increase hunger and gastric acid. Also increases gastric motility
Inducers: hypoglycemia and low body weight
Inhibitors: stomach distention
Leptin specifics
Location = adipose cells
Targets ventromedial hypothalamic brain cells
Functions to produce satiety (feels full)
Inducers: insulin and emotional stress
Inhibitors: short term fasting
Prader -willi syndrome
Birth defect where ghrelin is constant high
- causes obesity, short stature and intellectual disabilities
Symptoms:
- behavior issues
- intellectual issues
- stunted growth
- delayed puberty
- constantly hungry = obesity
What two nuclei influence the mesocorticolimbic reward system as it pertains to eating?
Medial arcuate
- encodes pleasure for eating
Lateral arcuate
- encodes pleasure for satiety
both tend to balance each other out, however in lesions, one can overwhelm the other and affect personality
What other hormones outside of leptin and ghrelin also play a role on influencing the arcuate hypothalamic nuclei?
Insulin and CCK
- promote POMC/CART action by agonist of LepR receptors on these neurons
- antagonize AgRP/NPT action by antagonism of the LepR receptors on these neurons
