Chapter 7 Flashcards
What is the main source of energy for the mammalian brain?
- glucose!
- (neurons have highest energy demand)
Distinguish homeostatic vs hedonic motivation to consume food
- homeostatic: energy balance
- hedonic: highly palatable foods
Stress-related changes in eating are usually related to (homeostatic/hedonic) control
hedonic!
What is the prandial state?
- after consuming a meal
- anabolism
- blood is filled w nutrients
- energy stored as glycogen and triglycerides
What is the postabsorptive state?
- fasting condition
- catabolism
- glycogen and triglycerides broken down to be used as fuel
Well-fed animals have:
- high blood conc of ___, ___, ___, and ___
- high stores of ____ and ____
- high ___ enzymes
- high ___, ___, and ___
Word bank:
- glucose, glucagon, insulin, leptin, glucocorticoids, amino acids
- free fatty acids, body fat in adipose tissue, glycogen in liver
- lipolytic enzymes, lipogenic enzymes, ketone bodies, circulating ghrelin
- CCK, NPY, melanin-concentrating hormone, a-melanocyte-stimulating hormone, orexin, corticotropin-releasing factor, cocaine/amphetamine regulated transcript, catecholamines
- high blood conc of glucose, amino acids, insulin, and leptin
- high stores of body fat in adipose tissues and glycogen in liver
- high lipogenic (fat-synthesizing) enzymes
- high CCK, a-melanocyte-stimulating hormone, and cocaine and amphetamine regulated transcript
Fasting animals have:
- high blood conc of ___ and ___
- high ____
- high ___ enzymes, ___, and ___
- high ___, ___, ___, ___, and ___
Word bank:
- glucose, glucagon, insulin, leptin, glucocorticoids
- free fatty acids, body fat in adipose tissue, glycogen in liver
- lipolytic enzymes, lipogenic enzymes, ketone bodies, circulating ghrelin
- CCK, NPY, melanin-concentrating hormone, a-melanocyte-stimulating hormone, orexin, corticotropin-releasing factor, cocaine/amphetamine regulated transcript, catecholamines
- high blood conc of glucagon and glucocorticoids
- high free fatty acids
- high lipolytic enzymes, ketone bodies, and circulating ghrelin
- high NPY, melanin-concentrating hormone, orexin, corticotropin-releasing factor, and catecholamines
What are orexigenics and anorexigenics?
- orexigenic: appetite stimulant
- anorexigenic: reduces appetite
During the postabsorptive phase, ___ secretion rises while ____ secretion falls
insulin; glucagon
Metabolism during the well-fed state:
- conversion of ___ to ___ in liver
- ___ is stored in liver and muscle
- ___ facilitates transport of glucose and amino acids into into muscle and fat cells
- conversion of amino acids to ___ in liver
- conversion of glucose to glucagon in liver
- glycogen is stored in liver and muscle
- insulin facilitates transport of glucose and amino acids into into muscle and fat cells
- conversion of amino acids to ketone bodies in liver
Metabolism during the fasting state:
- ___ are formed which can be used by brain when glucose is scarce
- ___ is released from the pancreas
- ____ breaks down stored glycogen in liver
- ____ in adipose tissue releases free fatty acids and glycerol
- ketones are formed which can be used by brain when glucose is scarce
- glucagon is released from the pancreas
- glycogenolysis breaks down stored glycogen in liver
- lipolysis in adipose tissue releases free fatty acids and glycerol
What is glycogenolysis?
- breakdown of stored glycogen in liver or muscles to provide steady supply of glucose for energy
- during fasting state
What is lipolysis?
- breakdown of adipose tissue into free fatty acids
- during fasting state
What is gluconeogenesis?
- production of glucose from amino acids
- occurs in liver in response to mild fasting
- during fasting phase
Type 1 diabetes can be characterized as insulin-(resistant/dependent) while type 2 as insulin-(resistant/dependent)
type 1 = dependent
type 2 = resistant
Distinguish type 1 and type 2 diabetes
TYPE 1
- beta c of pancreas destroyed by immune system
- less insulin so less glucose absorbed and more glucose in blood
- genetic, early onset, more rare
- managed by insulin injections
- INSULIN DEPENDENT
TYPE 2
- pancreas prod enough insulin but c are not responsive to it so glucose stays in blood
- lifestyle related, 80-90% of all diabetes
- INSULIN RESISTANT
(T/F) usually obesity PRECEEDS increased food intake
TRUE!!
Leptin is produced by ____ and circulates in concentrations proportional to ____. High levels signal (satiety/starvation)
adipose cells, proportional to total amount of fat in body
high levels signal satiety!
Why can’t we use leptin as a treatment for human obesity?
- bc they don’t lack leptin, more like leptin resistance
High levels of leptin (increase/decrease) appetite and (increase/decrease) energy expenditure
decrease appetite; increase energy expenditure
What role do insulin receptors play in metabolism? Where are they located?
- monitors of metabolic fuels (eg glucose levels in brain)
- located in brain (esp arcuate nuclei)
Insulin concentrations act similarly to (leptin/ghrelin), and (increase/decrease) with higher food intake
leptin; increase
Ghrelin (increases/decreases) food intake
increases
when do blood concentrations of ghrelin peak?
around time of meal onset
circulating concentrations of leptin and ghrelin are ____ correlated
inversely! (they act in opposition)
Distinguish lateral hypothalamic syndrome and ventromedial hypothalamic syndrome
- lateral: lesions to lateral hypothalamus cause anorexia
- ventromedial: lesions cause obesity
bilateral lesions of the lateral hypothalamus were shown to interfere with _____
ALL motivated behaviours (not just feeding)
What are the 2 opposing sets of neuronal circuitry in the arcuate nuclei of the hypothalamus?
- feeding stimulatory circuit
- feeding inhibitory circuit
The feeding stimulatory circuit acts in response to (increased/decreased) ___ and ___ levels while the inhibitory circuit acts in response to (increased/decreased) ___ and ___ levels
decreased leptin and insulin; increased leptin and insulin
The feeding inhibitory circuit inhibits ____ and activates ____ which both lead to decreased food intake
inhibits NPY/AgRP neuron; activates POMC/CART neuron
The feeding stimulatory circuit inhibits ____ and activates ____ which both lead to increased food intake
inhibits POMC/CART neuron; activates NPY/AgRP neuron
Ghrelin is released by the ___
gut
What are the 5 central anabolic effectors (peptides that promote food intake)?
- neuropeptide Y (NPY)
- agouti-related protein
- melanin-concentrating hormone (MCH)
- pancreatic polypeptide
- orexin
what are anabolic effectors?
peptides that promote food intake
what are catabolic effectors?
peptides that inhibit food intake
What are the 2 central catabolic effectors (peptides that inhibit food intake)?
- melanocortin
- cocaine/amphetamine regulated transcript (CART)
POMC (proopiomelanocortin) is the pituitary precursor for melanocortins ___, ____ and ____
a-MSH, b-MSH, and adrenocorticotropic hormone (ACTH)
Leptin and insulin (increase/decrease) POMC gene expression which leads to secretion of ___ to (inhibit/activate) feeding behaviour
increase; a-MSH to inhibit feeding
Leptin and insulin stimulate a(n) (anabolic/catabolic) pathway (____ neurons) and repress a(n) (anabolic/catabolic) pahway (____ neurons). Both pathways are located in the ___
- stimulate catabolic path (POMC/CART neurons)
- repress anabolic path (NPY/AgRP neurons)
- located in hypothalamus
_____ is a protein hormone and a primary hormonal factor that provokes satiety. It is produced by the ____
Cholecystokinin (CCK); prod by gut
Estrogens have (anabolic/catabolic) effects and androgens have (anabolic/catabolic) effects
catabolic (body fat loss); anabolic
____ is the most prominent system that controls appetite and motivational and emotional drives for food
the dopamine reward system
(T/F) dopamine and serotonin both play a role in feeding behaviour
TRUE, serotonergic signaling may reduce reward-related food consumption
acute physical or emotional distress does what to feeding behaviour?
induces increased intake of comfort foods even when not hungry
What findings suggested that the effect of food consumption on ghrelin may be psychologically mediated?
- study w 2 diff milkshake labels (indulgence vs health shake)
- when ppl thought they were having the unhealthy shake, ghrelin went way up before consumption and then way down after
- when ppl thought they had healthy shake, ghrelin barely went up and barely went down after consumption
What is Ozempic?
- weight loss drug
- mimics GLP-1: promotes insulin production, slows digestion, suppresses hunger cravings
- similar weight loss effectiveness to surgery!
