Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
61 Cards in this Set
- Front
- Back
|
Where is the hypothalamus located?
|
Small structure located just below the thalamus in the diencephalon (forebrain)
|
|
|
What are the major jobs of the hypothalamus?
|
-Controlling homeostasis
-Control of hormones -Regulates the balance of: water, salt, nutrients, glucose, sex hormones -Regulating emotional arousal |
|
|
What is homeostatsis?
|
maintenance of a stable internal environment
|
|
|
What are hormones?
|
bloodborne communication molecules
|
|
|
What is neuroendocrine signaling?
|
the release of hormone into the blood that then travels to the organ in the periphery (signal takes longer to be received and lasts longer)
|
|
|
What are the types of hormones?
|
-Amino acid derivatives
-Peptides and proteins -Steroids |
|
|
What is an example of an Amino acid derivatives?
|
Epinephrine
|
|
|
What are Peptides and proteins and what is an example?
|
-Short and long chains of amino acids
-Neuropeptide Y (NPY), Leptin, Insulin |
|
|
What are steroids and what is an example?
|
-Synthesized from cholesterol (fat)
-Fat-soluble – able to enter cells and bind to receptors in cytoplasm or nucleus -Testosterone, estrogen, progesterone, cortisol |
|
|
What are Endocrine Glands?
|
sites of hormone release
|
|
|
The hypothalamus is part of what system?
|
limbic system
|
|
|
What does the limbic system involved in?
|
emotion, cognition and motor behavior
|
|
|
The hypothalamus receives neurochemical signals from other members of the limbic system and sends....
|
neurochemical AND hormonal signals back to the limbic system and to the
periphery |
|
|
All of the nuclei enable the hypothalamus to regulate....
|
ALL aspects of homeostasis
|
|
|
What is the master gland?
|
The nuclei in the hypothalamus that control the endocrine system
|
|
|
The hypothalamus send neuroendocrine signals (hormones or
neural signals) to control.... |
the pituitary
|
|
|
What does the pituitary do?
|
releases hormones into general circulation to target endocrine glands throughout the body
|
|
|
What do the endocrine glands do?
|
release hormones into general circulation to influence cellular responses in many/all tissues of the body.
|
|
|
Where is the pituitary gland located?
|
stalk that hangs just below the hypothalamus
|
|
|
What are the 2 ways that the neurons in the hypothalamus affect neuroendocrine signaling from the pituitary?
|
1.)release neuro-hormones into the blood that stimulate or inhibit hormone release from the anterior pituitary gland
2) Direct innervation of the posterior pituitary gland |
|
|
How does the hypothalamus regulate homeostasis and emotional arousal?
|
by detecting a number of different hormones and responds by initiating
hormone cascades in the body |
|
|
When our body’s supplies
are low... |
our organs send signals to the
hypothalamus to initiate a hormone signaling cascade that will stimulate behavior to correct the problem |
|
|
When our body’s supplies
are high... |
our organs send signals to the hypothalamus and pituitary to “STOP” a hormone signaling cascade that will prevent behavior until supplies return to normal
|
|
|
The VMH (Ventromedial Nucleus) lesions increase...
|
insulin secretion
-nutrients from food get stored as fat & there is a reduction in fat breakdown -animal over-eats to compensate for lack of nutrients in blood -huge weight gain but then will stabilize at a higher weight |
|
|
What does the Arcuate nucleus do?
|
detects satiety hormones (leptin and
insulin) and regulates behavior through other nuclei |
|
|
High leptin and insulin excite...
|
Cocaine and Amphetamine Regulated Transcript (CART) neurons in the ARC which release CART into PVN and LH.
•CART activates PVN output to ant. pit increasing HPA and HPT. •CART inhibits LH to reduce “hunger” in limbic system. |
|
|
Low leptin and insulin lead to
activation.... |
of Neuropeptide Y neurons in the ARC which release NPY into PVN and LH.
•NPY inhibits PVN output to ant. pit decreasing HPA and HPT. •NPY excites LH to stimulate “hunger” in limbic system. |
|
|
Why are ob/ob mice 3X normal weight?
|
They lack the gene that encodes leptin (the fat detector that inhibits the
PVN) |
|
|
What are Leptin therapy drawbacks?
|
Obese people have abnormally high levels of leptin because they have abnormally elevated levels of body fat
-desensitized or mutant leptin receptors ->don’t respond to leptin injections |
|
|
The Hypothalamus and the Pituitary send hormonal signals to the....
|
Adrenal Glands
|
|
|
The Hypothalamus and the Pituitary send hormonal signals to the....
|
Adrenal Glands
|
|
|
What does the Hypothalamo-Pituitary-Adrenal (HPA) axis do?
|
-a critical regulator of our body’s response to stressful stimuli; key
function is to increase available energy. -Works in conjunction with your sympathetic nervous system for “fight or flight” situations; during time of “stress” both the HPA and sympathetic nervous system are activated together. -Unlike the sympathetic nervous system, the HPA axis helps cope with prolonged periods of stress (slowed response). |
|
|
Activation of the HPA axis initiates...
|
a cascade of hormone release that
ultimately increases the amount of cortisol and epinephrine in blood |
|
|
The hypothalamus receives neuronal
input from three brain regions that are involved in stress. What are they? |
-thinking about stress (cortex) -memories of stress (hippocampus)
-learned associations about stress (amygdala) |
|
|
Activation of the PVN stimulates...
|
the release of CRH (corticotropin-releasing hormone) that travels through the portal system and activates CRH receptors in the anterior pituitary
|
|
|
The pituitary has receptors for....
|
CRH
|
|
|
Activation of CRH receptors in the pituitary stimulates...
|
the release of ACTH (adrenocorticotropic hormone)
|
|
|
The ACTH travels in the blood and reaches the...
|
adrenal glands
|
|
|
ACTH binds to ACTH receptors in the...
|
adrenal cortex
|
|
|
ACTH receptor activation in the adrenal cortex causes the release of...
|
cortisol (a glucocorticoid)
|
|
|
Cortisol then circulates to target organs (incl. brain) where it binds to...
|
glucocorticoid receptors and increases energy for activity to cope or respond to stress
|
|
|
Each level of the HPA axis
contains... |
receptors to detect blood and brain levels of CRH, ACTH or cortisol
|
|
|
What is negative feedback?
|
When levels become too high, the HPA axis shuts itself off
|
|
|
Under chronic stress and repeated HPA axis activity, the negativefeedback that normally inhibits HPA axis will...
|
shut off
-overstimulated -> receptor desensitization -> HPA axis hyperactivity |
|
|
What contains nuclei that control hormones involved in sexual motivation?
|
hypothalamus
|
|
|
The stimulation of the release of hormones from sex organs involve...
|
a cascade of hormone release that begins in the hypothalamus
|
|
|
Stress Vs. Sex
CRH |
GnRH (gonadotropin releasing factor)
|
|
|
Stress Vs. Sex
ATCH |
Gonadotropic hormones (LH, FSH)
|
|
|
Stress Vs. Sex
Cortisol |
Testosterone, Estrogen & Progesterone (from gonads)
|
|
|
During puberty what becomes very active?
|
anterior pituitary
-release of growth hormone, ACTH and gonadotropic hormones |
|
|
What is mascinulization?
|
in males, levels of androgens (e.g.,
testosterone) are higher than estrogen |
|
|
What is feminization?
|
levels of estrogens are higher than androgens
|
|
|
What happens if there is a loss of sex hormone cascade prior to puberty?
|
sexual immaturity
|
|
|
What is the anterior hypothalamus?
|
A.k.a: INAH-3
Larger in heterosexual men, smaller in women & in homosexual Men???? |
|
|
What is the preoptic area?
|
Male & female sexual and parenting behavior
-Sexually Dimorphic Nucleus (males)-Activated by testosterone |
|
|
What is the suprachiasmatic nucleus?
|
Larger in homosexual men than heterosexual men
|
|
|
What is the ventromedial hypothalamus?
|
Female sexual behavior-activated by estrogen and progesterone
|
|
|
What is the medial preoptic area?
|
stimulated by testosterone and reduced testosterone (castration; aging; chronic stress) lowers sexual performance; size of sexually-dimorphic nucleus of the mPOA is correlated with testosterone levels
|
|
|
What is the ventromedial nucleus (VMH)?
|
stimulated by estrogen and progesterone; fluctuations in these hormones during the menstrual cycle account for fluctuations in sex drive
|
|
|
What is the suprachiasmatic nucleus?
|
-(important in sleep-wake cycles)
-larger in homo- vs. heterosexual men -contains more vasopressin neurons in homosexual men -blocking vasopressin receptors in brain of rats reduces sexual behavior |
|
|
What is significant about the INAH-3?
|
2 times larger in heterosexual males than females or homosexual males
|
