Lecture 65 Flashcards
Hypothalamic-pituitary unit regulates functions of what 3 glands
thyroid, adrenal, reproductive glands
Hypothalamic-pituitary unit controls s growth, _______, and osmo _______
milk production/ejection; osmoregulation
Hypothalamic-pituitary unit: What kind of connects are there
Neural and vascular connections
Hypothalamic-pituitary unit: Hormones produced by hypothalamus stimulate/inhibit release of hormones by
pituitary (particularly anterior poriton)
List the 2 lobes of the Pituitary
Anterior lobe (adenohypophysis) and Posterior lobe (neurohypophysis)
The stalk connecting the hypothalamus and the pituitary gland is called the
Infundibulum
Anterior lobe of pituitary lobe is called the
adenohypophysis
Posterior lobe of pituitary lobe is called the
neurohypophysis
what are the parts of the adenohypophysis
- pars tuberalis- in infundibular stalk
- pars intermedia
- pars distalis
what are the parts of the neurohypophysis
pars nervosa and infundibular stalk
Hypothalamic functions coordinated key functions such as
thirst, appetite, temperature regulation, autonomic nervous system
List some factors that influence the hypothalamus
Pain, sleep, emotions (fear, rage), olfactory, light, thoughts
List some Neurotransmitters that influence the hypothalamus
Dopamine, serotonin, norepinephrine, acetylcholine, GABA, _-endorphin
T/F the hypothalamus is randomly responding to information from areas like heart, repro, or GIT
F; constantly responding
Pituitary sits beneath hypothalamus in the _______
sella turcica (bone socket)
what part of the pituitary contains neurons descending from hypothalamus (supraoptic and paraventricular areas)
Posterior pituitary
(neurohypophysis)
what part of the pituitary is derived from neural tissue
Posterior pituitary
(neurohypophysis)
Posterior pituitary
(neurohypophysis): Hormones synthesized in hypothalamus and transported down axons secreted in the posterior as neuropeptides at the _______
Capillary plexus
what part of the pituitary is derived from primitive foregut tissue
Anterior pituitary
(adenohypophysis)
Hypothalamic-releasing and inhibiting hormones that regulate anterior pituitary function released from
terminal axons at the median eminence(where neurons end)
what two types of hormones regulate anterior pituitary function
Hypothalamic-releasing and inhibiting hormones
Anterior pituitary(adenohypophysis) have what and what hypophysial portal vessels
Long (located at median eminence) & short (located at lower infundibular stem) DOES NOT GO TO GENERAL CIRCULATION
Anterior pituitary is a collection of _______ cells
endocrine
Connection at the Anterior pituitary is both _______ and _______
neural and endocrine
What is the blood supply to the Anterior pituitary
venous blood directly from hypothalamus via portal system of capillaries
Hypothalamic hormones _______ what to anterior pituitary in _______ concentration
directly; high
Hypothalamic hormonesgenerally don’t appear in what
systemic circulation
Releasing and inhibiting hormones from hypothalamus released into hypophyseal portal veins at
median eminence
Hypothalamic hormone: Thyrotropin-releasing hormone(TRH) stimulates
Anterior pituitary hormone: thyroid-stimulating hormone(TSH) & prolactin
Hypothalamic hormone: Gonadotropin-releasing hormone(GnRH) stimulates
Anterior pituitary hormone: luteinizing hormone (LH), follicle-stimulating hormone (FSH)
Hypothalamic hormone: Corticotropin-releasing hormone(CRH) stimulates
Anterior pituitary hormone: adrenocorticotropin (ACTH)
Hypothalamic hormone: Growth hormone-releasing hormone (GHRH) stimulates
Anterior pituitary hormone: growth hormone (GH)
Hypothalamic hormone: Somatostatin (growth hormone-inhibiting hormone) inhibits
Anterior pituitary hormone: GH, prolactin
Hypothalamic hormone: Prolactin-releasing factor (PRF) stimulates
Anterior pituitary hormone: prolactin
Hypothalamic hormone: Dopamine (prolactin-inhibiting factor) inhibits
Anterior pituitary hormone: prolactin (primary inhibitor of prolactin), ACTH
Hypothalamic hormone: Dopamine (prolactin-inhibiting factor) stimulates
Anterior pituitary hormone: GH
_______ is the release point for hormones synthesized in the hypothalamus with ultimate release from posterior pituitary
capillary plexus
Trophic cells of the anterior pituitary include (5) and where do they “aggregate”
Thyrotrophs, Gonadotrophs, Corticotrophs, Somatotrophs, Lactotrophs; aggregate in regions within the anterior pituitary
Trophic cells of the anterior pituitary: Secretion of hormones is what in response to hypothalamic hormones. Some may have what variation
episodic (release of hormones or other biological signals in bursts or pulses rather than in a steady); diurnal (more in morning)
Somatotrophs make what hormone product
growth hormone
Lactotrophs make what hormone product
prolactin
Corticotrophs make what hormone product
corticotropin
Thyrotrophs make what hormone product
TSH and free alpha subunit
Gonadotrophs make what hormone product
FSH, LH, free alpha subunit
anterior pituitary hormone: TSH goes to what target tissue
Thyroid gland (T3, T4)
anterior pituitary hormone: LH goes to what target tissue
Gonads (testosterone, estrogen)
anterior pituitary hormone: ACTH goes to what target tissue
Adrenal glands (cortisol)
anterior pituitary hormone: GH goes to what target tissue
All tissues (muscle, adipose, etc)
anterior pituitary hormone: Prolactin goes to what target tissue
Mammary glands and gonads
anterior pituitary hormone: FSH goes to what target tissue
gonads
Regulation of thyrotroph secretion (TSH): Stimulators of TSH
TRH (from hypothalamus) and Decreases in T3, T4
Is T3 or T4 the active form? Which is more potent
T3
what is the stimulus for the hypothalamus to secrete TRH
thermal and caloric signals
Regulation of thyrotroph secretion (TSH): Inhibitors of TSH
Dopamine, Somatostatin, Increases in T3, T4
what hormone stimulates Gh secretion
Dopamine
ACTH initially secreted as
pre-pro-hormone Pro-opiomelanocortin (POMC)
ACTH intermediate
pro-hormone
T/F Pro-opiomelanocortin (POMC) gives rise to multiple hormones it just depends on route and enzyme
T; main one is ACTH
(also melanocyte-stimulating hormone)
Regulation of corticotroph secretion (ACTH): Stimulators of ACTH
CRH, Decrease in cortisol, ADH, Stress
How does ADH stimulate ACTH
modulates the release of ACTH to affect cortisol release in response to stress, particularly pregnancy and lactation
Regulation of corticotroph secretion (ACTH): Inhibitors of ACTH
Increase in cortisol, ACTH, Somatostatin, Dopamine
neurons controlling release of dopamine can be lost in _______ disease relative to horses
Pituitary Pars Intermedia Dysfunction (PPID) horses
what area is responsible for the secretion of ACTH in horses? in dogs?
Horse its thepars intermedia of anterior pituitary; Dog its the pars distalis of anterior pituitary
T/F in normal circumstances dopamine inhibits ACTH (tonic)
T
In PPID, neurons control the release of dopamine degenerate and what happens to ACTH
inhibition of ACTH is lost (cells producing ACTH are hyperactive)
Regulation of gonadotrophic hormones: LH and FSH regulate development, growth, _______ processes and sex steroid hormone secretion of the gonads of _______
reproductive maturation; either sex
Regulation of gonadotrophic hormones: Stimulators
GnRH, Activin (stimulates FSH secretion), Pheromones
Regulation of gonadotrophic hormones:
Gonadotrophin Inhibitors
Testosterone, Estrogen, Inhibin, Melatonin
Regulation of lactotroph secretion: what stimulates mammary gland development/ milk production and inhibits GnRH
Prolactin
Regulation of lactotroph secretion: Stimulators
TRH, Estrogen, Suckling, PRF
Regulation of lactotroph secretion: Inhibitors
Dopamine, Somatostatin, Prolactin
Regulation of lactotroph secretion: In this case, where does dopamine originate from
hypothalamus and secreted onto median eminence
Regulation of lactotroph secretion: Tonic inhibition of Dopamine in individuals who are NOT _______ or _______
pregnant or lactating
do we know much about PRF yet
nope
what inhibitor is lost in PPID in horses
DOPAMINE!!