Chapter 6 Flashcards
Arcuate Nucleus (ARC)
master hypothalamic centre for food intake control
- main part of hypothalamus
NYP/ AgRP
increase eating and reduce metabolism by releasing these peptides
POMC Neurons
decrease eating; release POMC and activate neurons that make you feel full therefore decreasing eating
- also glutamate
GABA
increases eating
Lateral Hypothalamus
brain region that initiates eating and controls aspects of feeding behaviour and metabolic responses
- gastric juice secretion
- insuline production
- process reward value of different food and how palatable different foods are
Orexin
increase eating and wakefullness in response to food deprivation
- excites the NPY neurons and inhibits the POMC neurons
Paraventricular Nucleus
regulate eating and metabolic process
- body temp, fat storage and cellular metabolism
- POMC stimulate this and that causes a reduction in eating
- NYP and AgRP inhibit this
Ventromedial Hypothalamus
brain region that reduces satiety and increase metabolism
- only receives info from POMC
Ghrelin
orexigenic peptide hormone synthesized in the stomach and released into bloodstream during fasting
- increases eating
- stimulates growth hormone release
- anticipatory hormone; released before each meal and drops immediately after you begin eating
Cholecystokinin
peptide hormone that is best known satiety signal, released by stomach and small intestine as food passes into duodenum
- limits mean size and aids digestion
- does not reduce total food intake
PYY
released in the intestine in response to food, suppressing appetite over longer period of time
- increased PYY, decrease total food intake
Leptin
peptide hormone secreted by fat cells that inhibits eating
- reduce meal size and total daily intake
BMI
quantifier of leanest or obesity calculated by dividing persons weight in kilograms by squared height in meters
- increased health risks; diabetes, high blood pressure, heart disease, stroke, cancer , alheizmers, shorter life spans
- cannot be characterized by lack of impulse control, inability to delay gratification, or maladaptive eating style
- factors that lead to obesity are common to the ones that lead to drug addiction
Obesity Gene
gene on chromosome 6 linked to obesity in mice, signified as ‘ob’
- recessive gene
Diabetes
gene on chromosome 4 linked to obesity in mice, signified as db
- recessive gene
Epigenetic
modifications to DNA that turn genes ‘on; or ‘off’ without changing dene’s DNA sequence
Methylation
attach methyl group to gene, which makes it difficult for a gene to function
Sleep Deprivation
plays a role in weight gain
- this is because when you are awake, your body is producing orexin which increases hunger
Basal Metabolism
energy required to fuel brain and other organs and to maintain body temperature
- metabolism will increase or decrease in order to defend a set joint weight
- goal of 10% weight reduction can be more practical than return to normal weight
- 10% reduction also associated with reduced risk for chronic disease
Anorexia
historical; cases dating back 300 years ago
- 56% heritability
plays a role in understanding eating disorders
Serotonin and Dopamine
- so largely involved in mood disorders and eating so we believe it plays
- using anti-depressants increases serotonin and decreases food binges for bulimia
- dopamine brings back the reward circuit for food making you feel good
Bulimia
up to 84% heritability
Motivation
set of factors that initiate , sustain, and direct behaviours
- unable to be explained solely in terms of outside stimuli
Instinct
complex behaviour that is automatic, unlearned, and unmodifiable occurring in all members of a species
- migration and parental behaviour in animals
- relying more on instinct less on learned behaviour
drive theory
body maintains condition of homeostasis
Homeostasis
the state in which any particular system is in balance or equilibrium
drive
an aroused condition
Incentive Theory
people motivated by external stimuli, not just internal needs
Arousal Theory
people behave in ways that keep them at preferred level of stimulation
Set Point
point of homeostasis for system to return to 37 degrees celsius
Ectothermic Animals
rely on certain behaviours to maintain body temperature
- lizards and snakes
Endothermic Animals
use energy reserves as well as environment to maintain a body temperature
- birds and mammals
Preoptic Area
brain area in mammalian hypothalamus that contains separate warmth-sensitive and cold-sensitive cells
- ex. tells body to shiver to warm up
Thirst
dry mouth and throat influence when to drink, not how much to drink
Hypovolemic Thirst
condition of thirst occurring when blood volume drops due to loss of extracellular water
- often singled by baroreceptors
Osmotic Thirst
condition of thirst occurring when fluid content decreases inside body cell
- outside environment is too salty
Subfornical Organ (SFO)
brain structure adjacent to third ventricle that sense and regulates internal water balance with OVLT
Organum Lamina Terminalis (OVLT)
brain structure adjacent to third ventricle that senses and regulates internal water balance with SFO
Circumventricular
outside blood-brain barrier with direct access to blood circulation
- SFO and OVLT
Osmoreceptor
fires more as volume decreases due to fluid loss
