test 1: lecture 11 Flashcards
walls of the 3rd ventricle is ___
hypothalamus
what are some things controlled by the hypthalamus
The balanced functioning of physiological processes and maintenance of an organism’s internal environment within a narrow range
Temperature
Blood volume
Blood pressure
Salinity
Acidity
Blood 02
Blood glucose
what three things does the hypothalamus control
ANS
endocrine system
motivated homeostatic behaviors (drinking, feeding)
hypothalamus controls the ANS by ___
Projections to sympathetic and parasympathetic neurons
hypothalamus controls the endocrine system by ___
Via anterior and posterior pituitary gland
hypothalamus controls motivated homeostatic behaviors by ___
Via connections with forebrain, limbic system, brainstem and spinal cord
hypothalamus is divided into which three regions
- Periventricular area:
periventricular nucleus - Medial Hypothalamic area
many well-defined nuclei - Lateral Hypothalamic area:
lateral preoptic nucleus
lateral hypothalamic nucleus
4 regions in the medial hypothalamic area
Preoptic area:
medial preoptic nucleus
lateral preoptic nucleus
- Anterior (supraoptic) region:
anterior hypothalamic nucleus
supraoptic nucleus
paraventricular nucleus
suprachiasmatic nucleus
- Middle (tuberal) region:
arcuate nucleus
ventromedial nucleus
dorsomedial nucleus
- Posterior (mammillary) region:
mammillary nuclei
posterior hypothalamic nucleus
what nucleus is in the preoptic area in the medial hypothalamic area
medial preoptic nucleus
lateral preoptic nucleus
what nuclei are in the anterior(supraoptic) region of the medial hypothalamic area
anterior hypothalamic nucleus
supraoptic nucleus
paraventricular nucleus
suprachiasmatic nucleus
What nucleus are found in the middle (tuberal) region of the medial hypothalamic area
arcuate nucleus
ventromedial nucleus
dorsomedial nucleus
what nucleus is found in the posterior (mammillary) region of the medial hypothalamic area
mammillary nuclei
posterior hypothalamic nucleus
the hypothalamus interacts with the posterior pituitary through ___
Magnocellular neurosecretory cells that run through the pituitary stalk and interact with the capillary bed to release oxytocin and vasopressin
___ secrete oxytocin and ADH
supraoptic nucleus
paraventricular nucleus
of the hypothalamus- released by magnocellular neurosecretory cells in the posterior pituitary
what hormones are released in the posterior pituitary?
oxytocin
ADH
- Uterine contractions
- Milk letdown reflex
- The “love hormone”
- Levels rise during sexual behavior-Promotes social bonding
oxytocin
(produced by supraoptic nucleus and paraventricular nucleus in the hypothalamus runs down magnocellular neurosecretory cells and released in the posterior pituitary)
___ Regulates blood volume and salt concentration
ADH (produced by supraoptic nucleus and paraventricular nucleus in the hypothalamus runs down magnocellular neurosecretory cells and released in the posterior pituitary)
how does hypothalamus control the anterior pituitary
paraventricular nucleus produce hormones → they travel down parvocellular neurosecretory cells and deliver hormones to the portal system
hypothalamic-pituitary portal system goes to anterior pituitary and will stimulate or inhibit cells in the anterior pituitary to either release or not release their own hormones
what cells innervate the anterior pituitary
parvocellular neurosecretory cells
paraventricular nucleus
HPA axis
stress response
release of cortisol (hypothalamus → parvocellular neurosecretory neurons release CRH (corticotropic releasing hormone→stimulates anterior pituitary to release ACTH which tells adrenal gland to produce cortisol)
cortisol will inhibit the release of CRH to stop cycle
what does cortisol do?
releases glucose into your bloodstream
increases blood pressure for increased physical activity such as running or fighting
Stimulates brain for more intense awareness.
Immune system activity is reduced to save energy for physical activity
made by adrenal cortex in response to ACTH, in response to CRH from the hypothalamus to the anterior pituitary by parvocellular neurosecretory neurons
what are some hormones released by pituitary
for the ANS sympathetic - what neurotransmitter is used
ACh for pre-ganglionic
norepinephrine (NE) for post ganglionic
for the ANS parasympathetic what neurotransmitter is used?
ACh for both pre and post ganglionic fibers
for sympathetic where are preganglionic?
in the spinal cord
thoracolumbar (T1-L2)
for parasympathetic where are the preganglionic
cervical and sacral
craniosacral
for parasympathetic where are the post ganglionic axons?
very short, close to target organ
for sympathetic where are post ganglionic axons?
synapse at peripheral ganglion close to spinal cord
Long second fiber
energy is stored in two forms ___
glycogen in liver and skeletal muscle
triglycerides in fat
___ when the blood is filled with nutrients
anabolism
___ during fasting, between meals
catabolism
will break down energy stores
___ rate at which the body uses energy while at rest to keep vital functions going, such as breathing and keeping warm.
BMR
basal metabolic rate
Brain monitors amount of ___ to maintain normal levels of fat energy stores
body fat
ob gene codes for a protein, called ___, which is released by adipocytes (fat cells)
leptin
____ leptin levels in blood activates hypothalamus and decreases feeding behavior
elevated
____ leptin levels in blood activates hypothalamus and increases feeding behavior
decreased
if you turn off ob - what does the brain think?
ob → leptin→ tells body there is fat
if you turn these off, no leptin= brain thinks fat reserves are low even if patient is obese
___ anatomical and physiological union of two animals – share blood supply
parabiosis
parabiosis of normal mouse and ob/ob mouse shows ___ is a bloodborne hormone
leptin
___ part of the brain can sense leptin levels
arcuate nucleus
arcuate nucleus in the hypothalamus control what two parts of the brain
paraventricular nucleus
lateral hypothalamic area
__ will stimulate the ANS to increase sympathetic tone and will influence the endocrine system to release ACTH and TSH which will __
paraventricular nucleus (→ anterior posterior by portal system)
increase metabolism and energy expenditure
___activated homeostatic motivated behaviors such as feeding.
lateral hypothalamic area
Leptin released by adipocytes (fat cells) activate leptin receptors on neurons in ___ nucleus of the hypothalamus.
arcuate
elevated leptin cause ___ neurons to release ___ that cause ___
arcuate
alphaMSH and CART
anorectic peptides → inhibit feeding, increase energy expenditure and metabolism
anorectic peptides cause ___ and are produced by __
anorectic peptides → inhibit feeding (inhibit lateral hypothalamic center) , increase energy expenditure and metabolism (stimulate the paraventricular nucleus)
examples are: alphaMSH and CART
produced by arcuate neurons in response to elevated leptin levels
CART and alpha MSH will inhibit ___ and stimulate ___
lateral hypothalamic center (will inhibit feeding)
paraventricular nucleus (will cause release of stimulating hormones from hypothalamus to anterior pituitary → release hormones that increase metabolism and mobilize energy stores, will also increase sympathetic tone)
CART and alphaMSH are produced by fat cells
Arcuate neurons responding to decreased leptin release the peptide transmitters___ which cause ___
NPY and AgRP →orexigenic peptides
stimulate feeding
decreases metabolism
decrease energy expenditure
NPY and AgRP
orexigenic peptide
produced when low leptin levels by the arcuate nucleus
will tell stimulate lateral hypothalamus → increase feeding
will inhibit paraventricular nucleus to tell pituitary to decrease ANS, decrease metabolism and decrease energy expenditure
feeling of hunger is by ___
AgRP and NPY produced by the arcuate nucleus in response to low leptin
compare leptin levels
Ghrelin is released when ___ and activates ___
stomach is empty
NPY/AgRP neurons of the arcuate nucleus stimulates feeding behavior
Gastric Distension will send a signal to ___ and tells body to ___
nucleus of the solitary tract via Vagus nerve → projects to hypothalamus and inhibits feeding behavior
CCK is produced in response to ___ and will signal ___ to cause___
fatty food in the intestine
nucleus of the solitary tract via Vagus nerve → projects to hypothalamus and inhibits feeding behavior
Insulin will activate ___ neurons
parasympathetic
insulin is released by ___ and cause ___ and activate ___
B cells in the pancreas in response to increased glucose
will cause glucose to be absorbed into the cells
will activate alphaMSH/CART neurons of the arcuate nucleus → will inhibit feeding (lateral hypothalamic area, increase metabolism and increase energy expenditure (paraventricular nucleus → pituitary)
serotonin is stores ___
raphe nuclei
what will cause an increase in serotonin levels?
sight or smell of food (carbs)
depression and anxiety are linked to lowered brain ___. antidepressants work to ___
serotonin.
increase serotonin levels
low serotonin levels reduce ___ that is why supplementing serotonin is a treatment for ___
satiety
bulimia (binge eating and vomiting)
___ highly vascularized structures located around the third and fourth ventricles lack of a blood–brain barrier
circumventricular organs
___ are points of communication between blood, brain and CSF
circumventricular organs (CVOs)
thirst due to decrease in blood volume
hypovolemia
volumetric thirst
hypovolemia will effect drinking behavior by ___
- Detected by pressure receptors in the cardiovascular system
- Signals ascend to nucleus of the solitary tract via Vagus nerve
- Solitary nucleus projects to Paraventricular nucleus of hypothalamus
- Vasopressin (ADH) released by posterior pituitary → acts on kidney to increase water retention and inhibit urine production
- Hypothalamus activates sympathetic division of ANS to constrict blood vessels → decrease in blood pressure in kidneys cause release of renin
renin → angiotensin 1 → angiotensin II will acts on subfornical organ to stimulate the paraventricular nucleus to release more ADH by the posterior pituitary
what CVO does renin act on and what causes this cascade?
subfornical organ
low blood volume sensed by CV system → solitary nucleua → paraventricular nucleus → release ADH by posterior pituitary
Hypothalamus activates sympathetic division of ANS to constrict blood vessels → decrease in blood pressure in kidneys cause release of renin
renin → angiotensin 1 → angiotensin II will acts on subfornical organ to stimulate the paraventricular nucleus to release more ADH by the posterior pituitary
Reduced blood flow to kidneys causes release of ___ into the blood. In the liver, renin converts angiotensinogen to angiotensin I which breaks down to angiotensin II
-
renin
Angiotensin II acts on the neurons of the ___, which stimulate neurons in the paraventricular nucleus causing release of vasopressin (ADH) by posterior pituitary
subfornical organ
Subfornical organ projects to ____ which produces thirst that motivates drinking behavior
lateral hypothalamus
___ – increase in blood salt
hypertonicity
(cause osmometric thirst)
Drinking behavior is stimulated by ___ and hypertonicity
hypovolemia
drinking pathway for hypertonicity
- Hypertonicity of the blood is sensed by neurons in the vascular organ of the lamina terminalis (OVLT)
- OVLT projects to the paraventricular nucleus of the hypothalamus → Posterior pituitary secretes vasopressin
Vasopressin acts on kidney to increase water retention and inhibit urine production
- OVLT projects to the lateral hypothalamus
- Lateral hypothalamus stimulates osmometric thirst, the motivation to drink water when dehydrated
OVLT is involved with ____ and stimulates ___
drinking due to hypertonicity
tells paraventricular nucleus → posterior pituitary to secrete ADH
tells lateral hypothalamus→ stimulates osmometric thirst, the motivation to drink water when dehydrated
OVLT= vascular organ of the lamina terminalis (OVLT)
Hypertonicity of the blood is sensed by neurons in the ___
vascular organ of the lamina terminalis (OVLT)
cold sensitive neurons
- Cold-sensitive neurons of the Anterior hypothalamus project to medial preoptic area of the hypothalamus
Medial preoptic area projects to parvocellular neurons of the paraventricular nucleus -> anterior pituitary → TSH → thyroid hormone, thyroxin= increases metabolism
- Medial preoptic nucleus activity activates sympathetic division of ANS → vasoconstriction and piloerection
Cold-sensitive neurons of the Anterior hypothalamus projects to Lateral hypothalamus → shivering and to seek warmth
- Cold-sensitive neurons of the Anterior hypothalamus project to ____ of the hypothalamus
medial preoptic area
Medial preoptic area projects to ___ → anterior pituitary → TSH → thyroid hormone, thyroxin= increases metabolism
Medial preoptic nucleus activity activates ___division of ANS → vasoconstriction and piloerection
parvocellular neurons of the paraventricular nucleus
sympathetic
when cold, ___ nucleus activity activates sympathetic division of ANS → vasoconstriction and piloerection
Medial preoptic
Cold-sensitive neurons of the Anterior hypothalamus projects to ___ → shivering and to seek warmth
Lateral hypothalamus
where are two places the cold sensitive neurons will go?
medial preoptic area and Lateral hypothalamus
1.Cold-sensitive neurons of the Anterior hypothalamus project to medial preoptic area of the hypothalamus
Medial preoptic area projects to parvocellular neurons of the paraventricular nucleus -> anterior pituitary → TSH → thyroid hormone, thyroxin= increases metabolism
- Medial preoptic nucleus activity activates sympathetic division of ANS → vasoconstriction and piloerection
Cold-sensitive neurons of the Anterior hypothalamus projects to Lateral hypothalamus → shivering and to seek warmth
warm sensitive neurons
- Warm-sensitive neurons of the Anterior hypothalamus projects to medial preoptic area of the hypothalamus→ parvocellular neurons of the paraventricular nucleus→ anterior pituitary → inhibit TSH →Metabolism is slowed
- Medial preoptic nucleus activity activates sympathetic division of ANS → Blood is shunted to the periphery to dissipate heat
Activity in Lateral hypothalamus causes the behavior of seeking shade, panting, and in humans, sweating – which helps cool the body
- Warm-sensitive neurons of the Anterior hypothalamus projects to ___ of the hypothalamus→ parvocellular neurons of the paraventricular nucleus→ anterior pituitary → inhibit TSH →Metabolism is slowed
medial preoptic area
when hot, Medial preoptic nucleus activity activates ___ division of ANS → Blood is shunted to the periphery to dissipate heat
sympathetic
when hot, ____causes the behavior of seeking shade, panting, and in humans, sweating – which helps cool the body
Lateral hypothalamus
why does metabolism slow when warm
decrease in TSH
- Warm-sensitive neurons of the Anterior hypothalamus projects to medial preoptic area of the hypothalamus→ parvocellular neurons of the paraventricular nucleus→ anterior pituitary → inhibit TSH →Metabolism is slowed
- Medial preoptic nucleus activity activates sympathetic division of ANS → Blood is shunted to the periphery to dissipate heat
Activity in Lateral hypothalamus causes the behavior of seeking shade, panting, and in humans, sweating – which helps cool the body
The___is involved with drives associated with maintenance of homeostasis
hypothalamus