Neural control of motivational behaviour Flashcards
what characterises areas called circumventricular organs? [1]
give some e.g.s xx
what characterises areas called circumventricular organs? [1]
areas where BBB is leaky, capillaires have fenestrations & substances can come in like hormone
which regions of the brain detect whether you are thirsty? [2]
- which ventricle are they close to? [1]
which regions of the brain detect whether you are thirsty? [2]
subfornical
OVLT
- which ventricle are they close to? [1]
third ventricle
the part of the brain that detects thirst is close to
corpus callosum
lateral ventricles
third ventricles
fourth ventricles
cerebral aqauduct
the part of the brain that detects thirst is close to
corpus callosum
lateral ventricles
third ventricles: OVLT & subfornical glands are located near
fourth ventricles
cerebral aqauduct
which of the following detects changes in osmolality?
median eminence
posterior pituitary
subcommissural organ
pineal gland
subfornical organ
which of the following detects changes in osmolality?
median eminence
posterior pituitary
subcommissural organ
pineal gland
subfornical organ & OVLT: contain osmoreceptors !
hypertonic blood is detected in the subfornical organ & OVLT (in wall of 3rd ventricle).
which nucleus do ^ activate when this occur? what does this cause to happen? [3]
- activates cells in mediate preoptic nucleus of hypothalamus
- projects to limbic system to drink & regulate thirst - we seek out water (greater activity = more thirsty)
ALSO
- subfornical organ activates cell in paraventricular nucleus & supraoptic nucleus: release ADH from posterior pit.
which nuclei are stimulated when blood is hypertonic? [3]
- medial preoptic nuclei
- paraventricular nuclei
- supraoptic nuclei
what are the three effects of ADH to decrease loss of water ? [3]
- increase aquaporins in CD
- increases perm. of urea in CD (helps increase reab)
- stimulates Na reaborb by increase Na/K/Cl2 transporter
what happens to body when in heat stress?
- lose water by sweat
- drink more to compensate
- body increase aldosterone (to replace Na+ lost)
- decreases ANP
= prevents hyponatramia
there is a delay between fluid intake alteration of plasma osmlality (10/20mins), but you feel not thirsty immediately after having a drink. how does this occur?
neural input to the brain from oropharnx that signals fluid intake (vagal afferents)
ADH release immediately inhibited
what happens to u if litro no water available in the desert lol?
conflict between water conservation and temp regulation:
- initially sweating continues, but body temp rises a few degrees
- urine flow stops completely
- become so dehydrated, cant sweat. over heat & get heat stroke and death
where is the main storage of energy in body? [1]
what happens to body weight and fat, despite fluctuations in food intake? [1] name? [1]
where is the main storage of energy in body? [1]
adipose tissue
what happens to body weight and fat, despite fluctuations in food intake? [1]
stays the same
name? [1]
**adipostatic model
baso controls feeding and maintains weight**
which part of the brain has the satiety centre?
thalamus
pituitary gland
cerebellum
hypothalamus
medulla
which part of the brain has the satiety centre?
thalamus
pituitary gland
cerebellum
hypothalamus
medulla
in rat studies:
lesions in the lateral hypothalamus produced which condition? [1]
lesions in the media hypothalamus produced which condition? [1]
specicially which medial nuclei? ^ [2]
in rat studies:
lesions in the lateral hypothalamus produced which condition: anorexia
lesions in the media hypothalamus produced which condition: **obesity
- arcuate nucleus
- periventricular nucleus**
hunger is a balance of internal and external cues. what are these?
internal cues:
- contraction of stomach
- glucose, insulin, ghrelin, CCK & leptin levels
external cues:
- sight and smell of food
BALANCE OF THE TWO controls hunger
which of the following is where internal cues (such as blood hormones are detected) when controlling hunger?
lateral hypthalamic nucleus
arcuate nucleus
periventricular nucleus
supraoptic nucleus
paraventricular nucleus
which of the following is where internal cues (such as blood hormones are detected) when controlling hunger?
lateral hypthalamic nucleus
arcuate nucleus
periventricular nucleus
supraoptic nucleus
paraventricular nucleus
lesions in which part of brain cause inability to detect internal signals? [1]
arcuate nucleus
which cell types in the arcuate nucleus
a) increase hunger? [2]
b) decreaes hunger? [2]
grehlin / insulin & other hormones travel to arcuate nucleus and interact with some cell types:
increase hunger:
- Agouti-related peptitde (AGRP)
- neuropeptide Y neurones (NPY)
decrease hunger
- cocaine & amphethamine transcript neurones (CART)
- pro-opiomelanocortin (POMC)
& interact !!
which of the following hormones is the hunger hormone?
leptin
insulin
ghrelin
neuropeptide Y
CCK
which of the following hormones is the hunger hormone?
leptin
insulin
ghrelin
neuropeptide Y
CCK
ghrelin is mainly released from which part of the stomach? [1]
which nerve detects stomach contractions & causes release of ghrelin? [1]
ghrelin causes the release of which hormones from arcuate nucleus? [2]
ghrelin is mainly released from which part of the stomach? [1]
fundus (but also pancreas & ileum)
which nerve detects stomach contractions & causes release of ghrelin? [1]
vagus nerve detects stomach contractions and signals to brainstem & hypothalamus to release ghrelin
ghrelin causes the release of which hormones from arcuate nucleus? [2]
neuropeptide Y
agouti related peptide
what does ghrelin cause the release of ? [3] & inhibit [2] in arcuate nucleus
ghrelin in the arcuate nucleus
- stimualtes
i) agouti-related peptide (AGRP) & neuropeptide Y (NPY): mediate hunger sensation
ii) dopamine pathway when eating - inhibits POMC & CART: satiety signalling
where is cholecystokinin released from?
pancreas
stomach
small intestine
bile duct
oesphogus
where is cholecystokinin released from?
pancreas
stomach
small intestine
bile duct
oesphogus
what it the role of CCK? [2]
where does it travel after release from small intestine? [1]
what it the role of CCK? [1]
release of digestive enzymes from pancreas
produces satiety !!
where does it travel after release from small intestine? [1]
arcuate nucleus in hypothalamus
which hormone causes nausea?
insulin
ghrelin
leptin
GLP-1
CCK
which hormone causes nausea?
insulin
ghrelin
leptin
GLP-1
CCK
what is GLP-1?
role on:
- satiety [1]
- insulin & glucagon levels[1]
- gastric emptying [1]
Glucagon like peptide -1
- inhibits gastric emptying = produces feeling of fullness
- stimulates: insulin secretion & decreases glucagon (lowers blood glucose)
- produces rapid satiety
CCK, GLP-1, insulin & other peptides stimulate which neurones in the arcuate nucleus? [2]
what effect does this have on satiety? [1]
CCK, GLP-1 & other peptides stimulate which neurones in the arcuate nucleus? [2]
POMC
CART
what effect does this have on satiety? [1]
stimulates satiety
what is pancreatic peptide YY hormone’s role?
effect on satiety? how?
what is pancreatic peptide YY hormone’s role:
effect on satiety?
increases ileal absorbtion and slows gastric emptying
which of the following is produced by adipose tissue?
insulin
ghrelin
leptin
GLP-1
CCK
which of the following is produced by adipose tissue?
insulin
ghrelin
leptin
GLP-1
CCK
what does circulating leptin reflect in the body? [2]
what does circulating leptin reflect in the body? [2]
- *total amount of adipose tissue;**
- *therefore gives brain a reading of total energy storage**
which of the following is does not rise rapidly after a meal?
insulin
ghrelin
leptin
GLP-1
CCK
which of the following is does not rise rapidly after a meal?
insulin
ghrelin
leptin: not related to food intake !!
GLP-1
CCK
damage to arcuate nucleus & periventricular nuclei would cause what pathology? [1]
damage to arcuate nucleus & periventricular nuclei would cause what pathology? [1]
overeating and obesity (due to loss of ability to detect hormones releesed from gut
what are reward pathways of the brain ? & where ?
actions of the orofacial muscles during drinking or feeding activate dopamine neurons in the ventral tegmental area of the brainstem: activate **nucleus accumbens (frontal lobe)
e.g.-**
drinking water = enjoy if thirsty or not (important for suckling)
- feeding = pleasurable
what has happened to reward pathway for individuals with anorexia?
reward pathway has come uncouple from the system fod food intake
