Feeding 2 Flashcards
Where does the output from the arcuate nucleus go?
Paraventricular nucleus of the hypothalamus (PVN)
what happens when the axons from the satiety cells of the arcuate nucleus deliver an excitatory message to the PVN
Arcuate Nucleus -> + PVN -> inhibits the Lateral Hypothalamus
Releases melanocortins (induces satiety)
What happens when there is input from the hunger cells of the arcuate nucleus
Arcuate Nucleus -> inhibits the PVN -> keeps lateral hypothalamus active
Disinhibits the lateral hypothalamus
What are
GABA
Neuropeptide Y (NPY)
Agouti-related peptide (AgRP)
Inhibitory transmitters in hunger
What happens when you inject NPY and AgRP
blocks satiety action of the paraventricular nucleus and provokes overeating and extreme hunger
what is the role of orexin in feeding and hunger
increases animal’s persistence in seeking food
influences response to incentives and reinforcement in general; whether a food is worth seeking out again
What happens if we shut down the PVN
Will begin to consume large meals nonstop causing “binge eating” behaviour
where is orexin released
Lateral Hypothalamus
What are the feeding related functions of the lateral hypothalamus
Controls insulin secretion (determines the insulin needed)
Alters taste responsiveness
what happens when you stimulate the lateral hypothalamus
increases the drive to eat
damage to this area will create and aversion to food and water
what is the Lateral Hypothalamus activated by
Ghrelin
what does the Nucleus Accumbens do in feeding
Control of ingestion and swallowing and is the pleasure centre (high activity when enjoying food)
what does the Nucleus of the Tractus Solitarius (NTS) do
provides information about texture
what are the functions of the axons of the Lateral Hypothalamus
Affects the. taste sensations and salivation response to tastes
causes cortical cells to increase response to taste, smell or sight of food
increases pituitary gland’s hormone secretion that increases insulin secretion
controls digestive secretions
food reward
What do outputs from the Ventromedial Hypothalamus (VMH) do
inhibits feeding
what does damage to the nucleus in the VMH do
leads to overeating and weight gain
-> normal sized meals but more frequent eating
-> stomach motility - stomach empties faster than normal
What two structure inhibit feeding and what two structures promote feeding
PVH + VMH (Inhibit)
Acuate Nucleus + LVN (Promotes)
What is Prader-Willi Syndrome
Genetic Condition
-> marked by intellectual disability, short stature, and obesity: high blood levels of Ghrelin
What happens to people with a mutated gene for the receptors for melanocortin
overeat
what is melanocortin responsible for
responsible for satiety,
Will you still experience hunger when melanocortin is released?
Yes
What is Bulimia Nervosa
Eating disorder in which people alternate between extreme dieting and binges of overeating 3-4 portions
force vomiting after eating (purging) : chronically hungry
“extreme dieting”
increased release of ghrelin & alternations of several other hormones and transmitters
resembles drug addiction
What is Anorexia Nervosa
Refusal to eat enough to maintain healthy body weight
exaggerated fear of getting fat -> will draw themselves fat in clinic
many experience Psychosis -> voices that call them fat
may engage in excessive exercise
altered dopamine levels lack of interest in things they used to enjoy (consequence and not a cause of anorexia)
