Regulation of Food Intake Flashcards
(49 cards)
What area of the brain is critical in the regulation of food intake, processing afferent and efferent signals based on interconnecting nuclei?
Hypothalamus
The hypothalamus is subdivided into interconnecting nuclei, that include ____ (there are 5)
Arcuate nucleus (ARC) Paraventricular nucleus (PVN) Ventromedial nucleus (VMN) Dorsomedial nucleus (DMN) Lateral hypothalamic area (LHA)
The hypothalamus receives crosstalk inputs from:
- Neural signals from the GI tract that provide _____ info about stomach filling
- Chemical signals from nutrients in the blood (glucose, amino acids, and fatty acids) that signify _______
- Signals from gastrointestinal hormones
- Signals from _____ released by adipose tissue
- Signals from the _____ ____ (sight, smell, and taste) that influence feeding behavior
Sensory
Satiety
Hormones
Cerebral cortex
The ______ nucleus of the hypothalamus is one of the best characterized brain regions as it relates to the control of feeding behavior due in large part to the presence of 2 distinct neuronal populations
Arcuate
The arcuate nucleus of the hypothalamus is one of the best characterized brain regions as it relates to the control of feeding behavior due in large part to the presence of 2 distinct neuronal populations
What are these populations?
- Pro-opiomelanocortin (POMC) anorexigenic neurons
- Neuropeptide Y (NPY)/agouti-related peptide (AgRP) orexigenic neurons
[signals from the periphery result in changes in the activity of these 2 neuronal subpopulations and the release of their respective neuropeptides influence feeding behavior and energy expenditure]
______ is a hormone that stimulates the POMC anorexigenic pathway and inhibits the _______ pathway, resulting in _______ food intake
Leptin; orexigenic; reduced
POMC neurons suppress appetite by releasing ________ stimulating hormone which is an agonist at the corresponding anorectic receptors
Alpha-melanocyte
[agonist at anorectic melanocortin-4 receptors]
______, a hormone secreted from the stomach, activates AGRP-NPY neurons and _______ food intake
Orexigenic effects are mediated through ____ receptors of NPY, which are located in the second order nucleus (not the arcuate anymore)
Ghrelin; stimulates
Y1
Agrp and Npy ______ food intake and _______ energy expenditures, causing weight _______
Stimulate; decrease; gain
A decrease in what hormone stimulates the expression of AgRP and NPY and suppresses POMC and CART, thereby increasing food intake and decreasing energy expenditure?
Leptin
What gene mutation is the most common cause of monogenic obesity in humans?
Does this gene involve anorexigenic or orexigenic pathway?
MC4R - can be used by EITHER anorexigenic or orexigenic!
______ and _____are important in regulating food intake and energy balance.
What are the effects of activation vs. inhibition of these genes?
MCR-3; MCR-4
Activation reduces food intake while increasing energy expenditure
Inhibition of MCR-3 and MCR-4 greatly increases food intake and decreases energy expenditure
[MCR3 is in arcuate nucleus associated with AGRP/NPY or POMC/CART neurons, MCR4 is in hypothalamus associated with second order neuron]
The secretion of Ghrelin signals that you are hungry 3-4x/day in coordination with _________ rhythm
Circadian
Where is the leptin hormone released from?
Adipose tissue
The GI tract is one of several organs that contribute to the peripheral signaling of food intake and satiety
_____-mediated reflexes are recognized as being critical to the neural control of energy homeostasis, particularly the short-term (homeostatic) and longer-term (hedonic) control of appetite and food intake
______, ______, and _____ all act as NTs/modulators within the brainstem to affect afferent and efferent responses via ____ nerve either directly or indirectly
Vagal
CCK, GLP-1, 5-HT; vagus
Afferent signals from the ________ travel via vagus nerve to the GI tract and hepatic portal system
Nucleus tractus solitarius (NTS)
Efferent information travels on vagus n. from the ______, which is involved in regulation of:
GI _____ and _____ functions
_______ hepatic glucose production
______ glycogen synthesis
_______ pancreatic endocrine (insulin) and exocrine secretion
DMN (dorsal motor nucleus)
Motor; secretory
Decreased
Increased
Increased
_____ = potent appetite stimulator produced by the stomach and regulated by feeding status
Ghrelin
When does Ghrelin secretion peak?
Before meals - makes people feel like eating
[levels fall once food is eaten]
Ghrelin stimulates appetite by activating hypothalamic ____-secreting neurons via ____ receptors
It also increases _____ hormone secretion
NPY; Y1
Growth
Where are the receptors for Ghrelin located? (i.e., in what nuclei of the brain?)
Arcuate nucleus
Lateral hypothalamic area
Accumbens nucleus
Ventral tegmental area
Fat cells produce _____ and secrete it into the bloodstream, where it normally suppresses ghrelin release
Leptin
Stimulation of leptin receptors initiates multiple actions that decrease fat storage including:
Decreased production of appetite stimulators in the hypothalamus such as ____ and _____
Activation of _____ neurons, causing release of a-MSH and activation of ______ receptors
Increased production of ________ hormone in the hypothalamus, which decreases food intake
Increased _____ nerve activity which increases metabolic rate and energy expenditure
Decreased _____ secretion by pancreatic beta cells, which decreases energy storage
NPY; AGRP
POMC; melanocortin
Corticotropin-releasing
Sympathetic
Insulin
Insulin is produced by the _____ cells of the _____ pancreas
It regulates glucose uptake, storage of absorbed nutrients, and caloric or energy balance
It can be transported across the _____ and bind receptors present in areas of the hypothalamus that control food intake, positively acting on _____ and negatively acting on _____
Beta; endocrine
BBB; POMC; NPY
