Hypothalamus and pituitary Flashcards
What is the Arcuate nucleus?
Base of the brain
Base of the brain, food intake control
What is the para ventricular nucleus?
Sits adjacent to the third ventricle
A nucleus of the hypothalamus
What nucleus of the hypothalamus sits next to the optic tract and what does it do?
Body temp
Supra optic nucleus
What is the anterior pituitary?
Adenohypophysis
What is the median eminence (infundibulum)?
The intersection of the pituitary and the hypothalamus
Relays information
What is the posterior pituitary?
Neurohypophysis
What does the posterior pituitary release?
Vasopressin or oxytocin into the systemic circulation
Peptide hormones
What synthesizes vasopressin and oxytocin?
The magnocellular neurons in the:
Supraoptic nucleus (SON) Paraventricular nucleus (PVN)
Where are vasopressin and oxytocin stored and released?
The posterior lobe
What projects to the supraoptic nucleus of the hypothalamus?
The solitary nucleus (medulla)
What projects to the PVN of the hypothalamus?
The limbic system (motivation and emotions)
Where do your Baroreceptors go?
The hypothalamus
What is the major stimulus(3) and responses for vasopressin?
- Increased osmolatity (too much sodium) –> increase water resorption by kidney
- Hypovolemia (low blood vol) –> water resorption
Both of these are anti-diuretics
-hypotension (low BP) –> vasoconstriction and water resorption
What is the main response to vasopressin?
Increased water resorption by the kidney
Vasoconstriction with low BP
What are the main stimuluses and responses for oxytocin?
- suckling –> milk ejection via smooth muscle contraction in breast
- uterine stimulation (newborn) –> smooth muscle contraction in uterus
What is the main response of oxytocin?
Smooth muscle contraction (female genitalia)
Also can help bonds between people
What does the anterior lobe of the pituitary make for hormones? (Stim–>response)
- Somatomammotropins
- GH - exercise, stress, and sleep (slow wave)
- ->tissue growth and metabolism
- prolactin - suckling! stress –> development of mammary tissue and lactation - Glycoproteins
- TSH - exposure to cold –> increase of thyroid hormone –> increase cell metabolism –> heat
- FSH - hypothalamic peptide –> spermatogenesis and development of ovarian follicle
- LH - hypothalamic peptide –> spermatogenesis and stim testosterone! initiates ovulation and stimulates progesterone - Opiomelanocortin peptides (POMC)
- ACTH - stress –> adrenal cortex secretion of cortisol
- BETA Endorphin - stress –> opiate like, analgesia
What are the two gonadotropins?
Tropins do release, gonado is gonads, release from gonads
FSH
LH
What is cortin?
Adrenal cortex
What test can be used clinically to test for the anterior pituitary lobe?
Give some insulin
Insulin induced hypoglycemia –> cortisol, ACTH, beta endorphin, prolactin, GH
What is the pathway of anterior lobe activation?
Parvocellular neuron by hypothalamic releasing hormone into the median eminence –> either excite or inhibit release of hormones –> primary capillary bed –> portal vein –> secondary capillary bed –> stimulation of specific hormone release
What are the six hypothalamic releasing hormones?
Excitatory (release)
- TRH –> TSH
- GnRH –> LH and FSH
- CRH –> ACTH and Beta-endorphins
- GHRH –> GH
Inhibitory
- somatostatin –> GH (net excite)
- dopamine –> prolactin (net inhib)
What hormonal changes occur after pituitary stalk section or cut?
All decrease (no excitation) accept prolactin (only under inhibitory control)
What is diabetes insipidus caused by?
Loss of vasopressin
- Head trauma by severing pituitary stalk
- Autoimmune destruction of magnocellular neurons
- Idiopathic
What are symptoms of diabetes insipidus?
- Polyuria
2. Polydipsia (excessive drinking)
What is the treatment of diabetes insipidus?
Vasopressin that only affects the kidneys
Desamino VP –> no increased BP
What is galactorrhea-amenorrhea?
Inappropriate lactation (increase blood prolactin) Cessation of menstration
What is the etiology of galactorrhea-amenorrhea?
Microadenoma that releases prolactin
Can turn off FSH and LH –> cessation of menstration (no pregnancy)
How do you treat galactorrhea-amenorrhea?
Surgery (tumor removal)
Pharmacology - dopamine receptor agonist
