Eating Behaviour Flashcards
Behaviour
The response of an organism to a stimulus
Behaviours can be…
- Unconscious
- Conscious
Higher-level voluntary or conscious behaviours require…
Motivation
Motivation is…
The driving force behind a behaviour and can be simple (need to urinate), or complex (need to sing and dance when happy)
WC model
- The water fills up (increasing motivation) until it reaches its limit
- Flushing releases the behaviour and the motivation is low
- Gradually the motivation builds up again until there needs to be another release
The more basic survival behaviours are controlled by…?
The hypothalamus
What does the hypothalamus develop from?
The diencephalon
A lesion on both sides of a rat’s lateral hypothalamus caused?
Anorexia
Bilateral lesions of the venteromedial hypothalamus caused?
Overeating and obesity
Lateral hypothalamus was known as?
Hunger centre
Venteromedial hypothalamus was known as?
Satiety centre
Kennedy (1953)
Proposed that the brain monitors fat levels and acts to maintain them (lipostatic hypothesis)
Coleman (late 1960s)
Proposed a soluble factor in obese mice (from the ob gene) fooled the brain into thinking fat levels were normal, so the mouse continued to eat
Friedman (1994)
Isolated protein leptin
Leptin
Is released by fat cells to decrease eating behaviour and increase energy expenditure
High levels of leptin act on receptors on neurones in the _____ _____ of the hypothalamus
Arcuate nucleus
The neurones that are activated contain neurotransmitters ____ and _____
Alpha-MSH and CART
These neurons send projections to…
- Lower brain stem and spinal cord
- Paraventricular nucleus of the hypothalamus
- Lateral hypothalamus
Stimulation of the _____ _____ acts to release TSH and ACTH from the ____ ____ ____
Paraventricular nucleus
Anterior pituitary gland
What do TSH and ACTH act on?
The thyroid and adrenal glands
What is the function of TSH and ACTH?
To increase the BMR
Stimulation of the brainstem and upper spinal cord increases ____ activity causing ____ body temperature and _____ BMR
Sympathetic
Raised
Increased
Feeding behaviour is inhibited by ____ motor activity through stimulation of cells in the ____ _____
Somatic
Lateral hypothalamus
What mimics the effect of raised leptin levels and what can the be called?
Injections of alpha-MSH and CART
Can be called anoretic peptides
Falling levels of leptin stimulate other neurones in the arcuate nucleus; these contain ____ and _____
NPY
AgRP
NPY and AgRP
- Inhibit TSH and ACTH secretion
- Activate the parasympathetic nervous system
- Stimulate feeding behaviour
- Are called orexigenic peptides
What is gherelin?
A hormone which is released into the bloodstream from an empty stomach and stimulates NPY and AgRP release (stimulates feeding)
What are short term signals in feeding called?
Satiety signals
Mood and food
Post-absorption of food (especially carbs) elevate serotonin levels
