04 Hypothalamus Flashcards
What does Gonadotropin releasing hormone act on
Luteotropes and folliculotrops
stimulates AP production of FSH and LH
*very similar across species
What does dopamine do
acts on lactotrophs to inhibit AP production of prolactin
What regulates ADH?
Osmoreceptors
blood vol
stress
circadian rhythm
What stimulates oxytocin production
suckling
Does the neurohypophysis release or synthesize OT and ADH
Neurohypophysis releases Oxytocin (OT) and antidiuretic hormone (ADH)
Primary function of hypothalamus
site of hormone production
What does growth hormone inhibitory hormone act on
Somatotrophs
inhibits AP production of GH
What is the target of prolactin
milk producing cells
What does GnRH do
Stimulate AP production of FSH and LH
What is the only hormone under inhibitory control
Prolactin is inhibited by domaine
What does Corticotropin releasing hormone (CRH) do
Acts on corticotrophs to stimulate AP production of ACTH
What does oxytocin do
stimulate smooth muscle contraction uterine contraction and milk let down
What is the target of oxytocin
Muscle cells
What does prolactin do
stimulate milk production
What does growth hormone releasing hormone act on
Somatotrophs
Stimulates AP production of Growth hormone (GH)
What does ADH to blood pressure
Increases blood pressure
How similar is GnRH across species
Very similar in different species
What is oxytocin’s role in males
Unclear
secreted during ejaculation
Promotes contraction of ductus deferens
What does Thyrotropin releasing hormone (TRH) do?
Acts on thyrotrophs of AP to stimulate TSH (thyroid stimulating hormone)
what is the primary function of posterior pituitary
Site of hormone storage and release
How how are hormones transported from the hypothalamus to the posterior pituitary
Axons of neuroendocrine cells
What does the hypothalamus communicate with?
Pituitary gland
What is inhibits oxytocin
Progesterone
What two important hormones does the neurohypopphysis secrete?
Oxytocin antidiuretic hormone (ADH)
What kind of tissue is the hypothalamus composed of
neural
What is another name for the anterior pituitary?
adenohypophysis
What is another name for the posterior pituitary?
neurohypophysis
What are the 3 parts of the adenohypophysis?
pars distalis
pars intermedia
pars tuberalis
hypothalamus role
site of hormone production
secretion of regulating hormones (factors)
synthesis of hormones
- oxytocin
- ADH
communicates with the pituitary gland via the hypothalamic -hypophyseal nerve tract and hypophyseal portal system
What type of cells produce hormones in the hypothalamus?
neuroendocrine cells
How are hormones transported from the hypothalamus to the anterior pituitary?
hormones secreted by neuroendocrine cells in the hypothalamus
enter portal vessels and are transported to the anterior pituitary
What is the structure and function of the neurohypophysis?
the posterior pituitary
an outgrowth of the hypothalamus composed of neural tissue
contains axons of neuroendocrine cells that project through the stalk from the hypothalamus
stores and releases: oxytocin and ADH
What type of hormones are
a peptide hormone produced by the hypothalamus
What is the function of oxytocin in females?
stimulates smooth muscle contraction
- uterus = parturition
- mammary glands = milk let down
How is oxytocin regulated?
up-regulated by estrogen
inhibited by progesterone
Describe the control of lactation
stimulus = suckling
induces hypothalamus to produce:
- prolactin (AP) > pituitary > milk production
- oxytocin (PP) > pituitary > milk release
Describe the control of lactation
stimulus = suckling
induces hypothalamus to produce:
- prolactin (AP) > pituitary > milk production
- oxytocin (PP) > pituitary > milk release
What diseases cause production or action of oxytocin to be inhibited?
none
pitocin
synthetic analog of oxytocin
has a longer half life than oxytocin but still short so must be given repeatedly or continuously
used clinically to facilitate parturition and milk let-down
What is ADH?
antidiuretic hormone
vassopressin
*similar across species
What is the function of ADH?
acts on kidney tubules
- decreases urine output
- increases water resorption
acts on sudoriferous (sweat) glands
- decreases sweating
constricts arterioles to increase blood pressure
Where are oxytocin and ADH produced and released?
synthesized by neurosecretory cells in hypothalamic nuclei
hormones are packed into secretory vesicles and travel to the neurohypophysis (posterior pituitary) via axons
Diabetes insipidus
more than one type abnormalities of ADH production (common) or response (rare)
lack of responsiveness to ADH
Excessive urination, dehydration, and thirst
Diabetes insipidus
more than one type abnormalities of ADH production (common) or response (rare)
lack of responsiveness to ADH
Excessive urination, dehydration, and thirst
What hormones are secreted by the hypothalamus? What type are they?
OXY, ADH
TRH, CRH, GnRH, GHRH/GHIH, Dopamine
Peptide hormones
What is the hypothalmus
region of the brain (diencephalon)
lies below the third ventricle at base of brain
important regulator of endocrine action
What is the pituitary gland (hypophysis)?
endocrine gland connected to the hypothalamus by infundibulum (stalk containing nerves and small blood vessels)
hypothalmic releasing and inhibiting hormones
produced and released in the hypothalamus
enter portal vessels and are transported to adenohypophysis
stimulate discrete cell types within anterior pituitary to secrete additional hormones
TRH, CRH, GnRH, GHRH/GHIH, DA
What hormones produced by the hypothalamus are highly conserved across species?
ADH
GnRH
CRH
