Control of food intake Flashcards
What are 2 factors that enable accommodation of stomach to occur?
VIP + NO
What is factor secreted in emptying of stomach?
Ghrelin
What is definition of hunger?
discomfort caused by lack of food and desire to eat -> strong physiological drive for food/sensation of emptiness in stomach
What is definition of appetite?
psychological desire/ drive to satisfy body’s needs of food-> hunger stimulated response
What is definition of satiety?
state of being full after eating food
What is definition of aphagia?
inability/refusal to swallow
What is definition of hyperphagia/ polyphagia?
abnormal desire for food
What is hypothalamus role in control of food intake?
control centre for appetite + food intake. controls hunger and thirst
What is role of pre-frontal cortex in control of food intake?
- food seeking behaviour. it determines our food eating behaviour
- integrates sensory info from inside and outside of body
receives emotional + cognitive info from limbic system
helps one make choices by translating all homeostatic + environmental info into adaptive behavioural response
What is role of limbic system in control of food intake?
- is complex system of nerves + networks in brain. areas concerned with instinct + mood. may control emotions.
- satiation of feeding behaviour behaviour is associated with motor planning + execution
What is lateral hypothalamus?
Hunger/thirst centre
What is ventromedial nucleus?
Satiety centre
What is function of dorsomedial nucleus?
Modulates energy intake (hunger centre)
What is function of paraventricular nucleus?
Modulates feeding behaviour
What is arcuate nucleus?
collections of neurons in hypothalamus -> neurones produce orexigenic signals
What is suprachiasmatic nucleus?
is where human body clock is located
Stimulation of ventromedial nucleus leads to…
aphagia
Lesions of ventromedial nuclei leads to….
hyperphagia
Stimulation of lateral hypothalamus lads to…
increased feeding
Lesions of lateral hypothalamus leads to…
aphagia
Where is switch?
in hypothalamus
How does orexigenic neurotransmitters affect feeding behaviour?
it increases appetite
How does anorexigenic neurotransmitters affect feeding behaviour?
it decreases appetite
What is circadian rhythm?
how does it affect food intake?
- sleep wake cycle
- 24hr internal clock that cycles between sleepiness and alertness
- limits food intake to certain times in some people
[blood glucose] stimulates what type of receptors in hypothalamus?
stimulates glucoreceptors
a decrease in [blood glucose] leads to…
upregulation of hunger
a increase in [blood glucose] leads to…
upregulation of satiety
How does distension of full stomach affect appetite?
it inhibits appetite
How does contraction of empty stomach affect appetite?
It stimulates appetite
What triggers CCK release?
Fat/lipid ingestion
Where is CCK found?
I cells in intestine/nerve endings
How does CCK affect appetite?
reduces appetite
inhibits further food intake
is satiety factor
What is effect of somatostatin on food intake?
inhibits further food intake
is satiety factor
What is adiponectin?
is factor released by insulin
has an impact on how we handle insulin or allows our body to regulate little bit how we respond to insulin effects
What are 2 effects of insulin of control of food intake?
has catabolic and anabolic effects
catabolic effect- decrease food intake
anabolic effect - increase food intake
Give 2 examples of orexigenic factors?
NPY and AgRP
How does glucagon secretion during feeding affect satiety + glucose release?
it promotes satiety + promotes glucose release
What is effect of amylin on feeding?
stimulated at same time as insulin
it reduces feeding
What type of agents are insulin, glucagon and amylin?
anorexigenic agents =reduce feeding
What is leptin? what does it control?
leptin is secreted by white adipose tissue which is endocrine gland. more white fat, more leptin secreted
controls fat stores by operating feedback mechanisms between adipose tissue + brain
increase in adipose tissue size -> increases leptin secretion
What is ghrelin?
Appetite inducing horome (orexin) -> stimulates hunger
released by stomach particularly upper oart, pancreas, adrenals in response to nutritional status. D1 cell type releases ghrelin
What is obestatin?
produced by epithelial cells of stomach
encoded by ghrelin gene but opposes the effects of ghrelin on food intake-> suppresses food intake, antagonises ghrelin induced food intake + growth hormone secretion
Acting on a1 receptor leads to …… feeding
decreased feeding
Acting on a2 receptor leads to …. feeding
increased feeding
