Term
What two hormones are released by the posterior pituitary, and what do they act on?
What type of hormones are they? |
|
Definition
ADH (kidney) and oxytocin (breast and uterus)
neuropeptides |
|
|
Term
Where are the cell bodies of ADH neurons contained?
Where are the cell bodies of oxytocin neurons contained? |
|
Definition
-In the supraoptic nuclei of the hypothalamus.
-In the paraventricular nuclei of the hypothalamus |
|
|
Term
| What is the connection between the hypothalamus and the posterior pituitary? |
|
Definition
|
|
Term
| What is the connection between the hypothalamus and the anterior pituitary? |
|
Definition
|
|
Term
What are the only cells in the body to receive high concentrations of the hypothalamic hormones?
Why? |
|
Definition
the cells of the anterior pituitary
because they are delivered by portal venous blood directly to the anterior pituitary from the hypothalamus |
|
|
Term
| What kind of hormones are secreted by the anterior pituitary? |
|
Definition
|
|
Term
| Which six hormones are secreted by the anterior pituitary? |
|
Definition
| thyroid-stimulating hormone (TSH), follicle-stimulating hormone (FSH), luteinizing hormone (LH), growth hormone, prolactin, and adrenocorticotropic hormone (ACTH) |
|
|
Term
All of the hormones released by the anterior pituitary are secreted by different cell types, except for which two hormones?
What is the name of the cell type that secretes them? |
|
Definition
|
|
Term
| What cell type in the anterior pituitary secretes growth hormone? |
|
Definition
|
|
Term
| What cell type in the anterior pituitary secretes TSH? |
|
Definition
|
|
Term
| What cell type in the anterior pituitary secretes ACTH? |
|
Definition
|
|
Term
| What cell type in the anterior pituitary secretes prolactin? |
|
Definition
|
|
Term
| Which anterior pituitary hormones are glycoproteins? |
|
Definition
|
|
Term
| Which subunits of TSH, FSH, and LH are identical? |
|
Definition
|
|
Term
| Which placental hormone is is structurally related to the TSH-FSH-LH family? |
|
Definition
| HCG. It is a glycoprotein with the identical α chain and its own β chain. |
|
|
Term
| Which hormone is coupled through a Gs protein to both adenylyl cyclase and phospholipase C? |
|
Definition
|
|
Term
| What are the seven classical endocrine glands? |
|
Definition
| Thyroid, parathyroid, pituitary, adrenal, pancreatic islets, gonads, placenta |
|
|
Term
| What are the two quantitative measures of degradation of hormones, which are also inversely related? |
|
Definition
|
|
Term
| Which area of the hypothalamus acts as a biological clock? |
|
Definition
| SCN (suprachiasmatic nucleus) |
|
|
Term
| What does the SCN send projections to? |
|
Definition
| to the subparaventricular zone and dorsomedial nucleus of the hypothalamus |
|
|
Term
| What does the SCN send inhibitory fibers to? |
|
Definition
| to neurons of the paraventricular nucleus (PVN) that control sympathetic output to the pineal gland |
|
|
Term
| What does the SCN regulate the circadian production of? |
|
Definition
| of melatonin by the pineal gland |
|
|
Term
| What is the pineal gland innervated by? |
|
Definition
| noradrenergic fibers from the superior cervical ganglion |
|
|
Term
| How does NE regulate melatonin secretion? |
|
Definition
NE activates melatonin secretion by a mechanism triggered by the activation of β1-adrenergic receptors.
Norepinephrine (NE) release is high at night and low during the day. |
|
|
Term
| How does the SCN control sympathetic output to the pineal gland? |
|
Definition
| Photosensitive retinal cells signals relay signals to the SCN. The SCN controls sympathetic output to the pineal gland via inhibitory fibers that project to neurons of the paraventricular nuclei (PVN). The paraventricular nuclei control the activity of the spinal preganglionic sympathetic neurons that innervate the superior cervical ganglion |
|
|
Term
| What makes prolactin unique among adrenal hormones? |
|
Definition
| It is under tonic inhibition |
|
|
Term
| What types of G proteins do the hypophysiotrophic hormones make use of? |
|
Definition
Somatostatin and dopamine - Gi (inhibit cAMP, activate G-protein gated K+ channels)
GHRH and CRH - Gs (stimulate cAMP)
GnRH and TRH - Gq (DAG and IP3) |
|
|
Term
| Which 3 anterior pituitary hormones are in the glycoprotein family? |
|
Definition
|
|
Term
| Which 2 anterior pituitary hormones are in the somammotropin family? |
|
Definition
|
|
Term
What are the three classes of endocrine hormones?
What are the precursors for each? |
|
Definition
amine - tyrosine
peptide - amino acids
steroid - cholesterol |
|
|
Term
|
Definition
|
|
Term
|
Definition
| prolactin-inhibiting factor, also called dopamine |
|
|
Term
|
Definition
| Somatostatin or Somatotropin release inhibiting factor |
|
|
Term
What does TRH stimulate the release of?
What kind of hormone is it?
What releases it? |
|
Definition
TSH and Prolactin
peptide
hypothalamus |
|
|
Term
What does CRH stimulate the release of?
What kind of hormone is it?
What releases it? |
|
Definition
|
|
Term
What does GnRH stimulate the release of?
What kind of hormone is it?
What releases it? |
|
Definition
FSH and LH
peptide
hypothalamus |
|
|
Term
What is the action of somatostain/SRIF?
What kind of hormone is it?
What releases it? |
|
Definition
to inhibit GH secretion
peptide
hypothalamus |
|
|
Term
What is the action of dopamine/PIF?
What kind of hormone is it?
What releases it? |
|
Definition
inhibit release of prolactin
amine
hypothalamus |
|
|
Term
What does GHRH stimulate the release of?
What kind of hormone is it?
What releases it? |
|
Definition
|
|
Term
| What is the only amine hormone released by the hypothalamus? |
|
Definition
|
|
Term
| What are the different stages of peptide hormone synthesis, and where does each take place? |
|
Definition
DNA -> mRNA (nucleus)
mRNA -> preprohoromone (ribosomes)
preprohormone -> prohormone (ER)
prohormone -> hormone (golgi) ->
hormone (secretory vesicles) |
|
|
Term
| Where are steroid hormones secreted and synthesized? |
|
Definition
| adrenal cortex, the gonads, the corpus luteum, and the placenta |
|
|
Term
| What are the seven steroid hormones? |
|
Definition
| cortisol, aldosterone, estradiol and estriol, progesterone, testosterone, and 1,25-dihydroxycholecalciferol |
|
|
Term
| What are the amine hormones? |
|
Definition
| Catecholamines (epinephrine and norepinephrine) and thyroid hormones (thyroxine [T4] and triodothyronine [T3]) |
|
|
Term
| What is the most common and important type of regulation of endocrine hormones: neural, positive feedback, or negative feedback? |
|
Definition
|
|
Term
| What is an ultrashort feedback loop? |
|
Definition
| When a hormone inhibits its own secretion |
|
|
Term
| When positive feedback does occur, what does it lead to? |
|
Definition
|
|
Term
| What are the two effects of LH and FSH on the ovaries? |
|
Definition
| ovulation and stimulation of estrogen secretion |
|
|
Term
| What are examples of hormones that exhibit positive feedback? |
|
Definition
oxytocin
estrogen
FSH and LH |
|
|
Term
| What must a target tissue contain to be able to respond to a hormone response? |
|
Definition
| receptors for the hormone that are coupled to cellular mechanisms that produce the physiological response |
|
|
Term
| What is sensitivity in relation to hormones? |
|
Definition
| the hormone concentration that produces 50% of the maximal response |
|
|
Term
| What are the two ways in which the responsiveness or sensitivity of a target tissue can be changed? |
|
Definition
| 1. by changing the number of receptors 2. by changing the affinity of the receptors for the hormone |
|
|
Term
| Can one hormone regulate the receptors of another hormone in a target tissue? |
|
Definition
|
|
Term
| What is an example of a hormone that downregulates its own receptors and those of another hormone? |
|
Definition
| progesterone; down-regulates its own receptors and those of estrogen in the uterus |
|
|
Term
| What are some examples of hormones that upregulate their own receptors? |
|
Definition
|
|
Term
| What is an example of a hormone that upregulates both its own receptors and those of other hormones? |
|
Definition
| estrogen increases its own receptors in the uterus and increases receptors for FSH and LH in the ovaries |
|
|
Term
| Which hormones use the tyrosine kinase action mechanism? |
|
Definition
|
|
Term
| Which hormones use the guanylate cyclase mechanism? |
|
Definition
|
|
Term
| Which hormones use the steroid hormone mechanism? |
|
Definition
glucocorticoids
thyroid hormones
estrogen
progesterone
testosterone
aldosterone
1,25-dihydroxycholecalciferol |
|
|
Term
| Which hormones use a PLC (IP3/Ca2+) mechanism? |
|
Definition
GnRH
GHRH
TRH
Angiotensin II
ADH (v1 receptor)
oxytocin
alpha 1 receptors |
|
|
Term
| Which hormones use the AC (cAMP) mechanism? |
|
Definition
ACTH
LSH
FH
TSH
ADH (V2 receptor)
HCG
MSH
CRH
Calcitonin
PTH
Glucagon
B1 and B2 receptors |
|
|
Term
How many subunits do G proteins have?
What is the catalytic subunit? |
|
Definition
three- alpha, beta, and gamma
alpha |
|
|
Term
| How does the AC mechanism work? |
|
Definition
GTP binds to Gsa subunit
Gsa subunit stimulates AC
AC converts ATP to cAMP
cAMP activates PKA
PKA phosphorylates proteins
Physiologic actions take place |
|
|
Term
| What can turn off the cAMP stiumulating PKA? |
|
Definition
|
|
Term
|
Definition
GTP binds to Gaq subunit
Gaq subunit binds to PLC
PLC turns PIP2 into IP3 and DAG
IP3 causes CA2+ release from ER or SR
Ca2+ release and DAG activate PKC
PKC phosphorylates proteins
Phosphorylated proteins cause the physiological actions |
|
|
Term
| How does the steroid hormone mechanism work (which also includes thyroid hormones)? |
|
Definition
| involves binding to cytosolic (or nuclear) receptors that initiate DNA transcription and synthesis of new proteins |
|
|
Term
| What are steroid hormone receptors? |
|
Definition
| monomeric phosphoproteins in the cytoplasm or nucleus |
|
|
Term
| What domain does the steroid hormone bind to on its receptor? |
|
Definition
|
|
Term
| What part of the steroid receptor binds DNA? |
|
Definition
|
|
Term
| After dimerizing, what part of the DNA does the steroid hormone-receptor complex bind to? |
|
Definition
| steroid-responsive elements (SREs) located in the 5' region of target genes |
|
|
Term
| Compare and contrast ADH (vasopressin) and aldosterone |
|
Definition
ADH - posterior pituitary hormone; peptide hormone
aldosterone: released by adrenal cortex (zona glomerulosa); steroid hormone |
|
|
Term
| Where are the cell bodies of ADH neurons are contained primarily? |
|
Definition
| supraoptic nuclei of the hypothalamus |
|
|
Term
| Where are the cell bodies of oxytocin neurons are contained primarily? |
|
Definition
| paraventricular nuclei of the hypothalamus |
|
|
Term
| What type of blood carries posterior pituitary hormones to the systemic circulation? |
|
Definition
| Venous blood from the posterior pituitary |
|
|
Term
| How are the hypothalamus and anterior pituitary directly linked? |
|
Definition
| hypothalamic-hypophysial portal blood vessels |
|
|
Term
| How does the blood supply of the anterior pituitary differ from that of other organs? |
|
Definition
| it is supplied mostly by venous blood |
|
|
Term
| What are the only cells in the body to receive high concentrations of the hypothalamic hormones? |
|
Definition
| the cells of the anterior pituitary |
|
|
Term
| What are the glycoprotein hormones? |
|
Definition
|
|
Term
| What precursor do all members of the ACTH family derive from? |
|
Definition
|
|
Term
| What are the members of the ACTH family? |
|
Definition
ACTH
MSH
beta endorphin
beta and gamma lipotrophin |
|
|
Term
| Where in the cell is POMC cleaved into the different members of the ACTH family by endopeptidases? |
|
Definition
|
|
Term
| What are the main ACTH family products in humans? |
|
Definition
| ACTH, γ-lipotropin, and β-endorphin |
|
|
Term
| Which products in the ACTH family contain MSH fragments that can cause skin pigmentation in humans if their blood levels are increased? |
|
Definition
The "fragment" that is left over from hydrolysis of the ACTH intermediate
ACTH
γ-lipotropin |
|
|
Term
| What causes skin pigmentation in Addison's disease? |
|
Definition
| increased ACTH and POMC because of adrenal insufficiency, caused by a lack of negative feedback |
|
|
Term
| Which two pathways regulate GH release? |
|
Definition
GHRH - positive on synthesis and secretion (induces somatotrophs in anterior pituitary to release GH) - Gs stimulates both AC and PKC)
Somatostatin - negative on secretion (keeps somatotrophs in anterior pituitary from releasing GH) - Gi acts on AC to inhibit |
|
|
Term
| What is one element of the GHRH-GH pathway that somatomedins postively instead of negatively feedback? |
|
Definition
| positive feedback on hypothalamus |
|
|
Term
| What are the main actions of growth hormone? |
|
Definition
-Diabetogenic effect
-Increased protein synthesis and organ growth
-Increased linear growth |
|
|
Term
| What does lack of growth hormone cause in children? |
|
Definition
| failure to grow, short stature, mild obesity, and delayed puberty |
|
|
Term
| What are possible reasons for a deficiency in thyroid hormone? |
|
Definition
*decreased secretion of GHRH due to hypothalamic dysfunction
*primary deficiencies of growth hormone secretion from the anterior pituitary
*failure to generate somatomedins in the liver
*deficiency of growth hormone or somatomedin receptors in target tissues (growth hormone resistance) |
|
|
Term
| How are conditions involving excess GH treated? |
|
Definition
|
|
Term
| How does prolactin inhibit ovulation? |
|
Definition
| By inhibiting GnRH secretion and ovulation (secondarily) |
|
|
Term
| What can prolactin deficiency be caused by? |
|
Definition
| either by destruction of the entire anterior lobe of the pituitary or by selective destruction of the lactotrophs |
|
|
Term
| What can prolactin excess be caused by? |
|
Definition
| by destruction of the hypothalamus, interruption of the hypothalamic-hypophysial tract, or prolactinomas (prolactin-secreting tumors) |
|
|
Term
| What are the only three tissues in which thyroid hormone does not upregulate oxygen use? |
|
Definition
| brain, gonads, and spleen |
|
|
Term
| What is the first step in the pathway for all steroid hormones? |
|
Definition
| the conversion of cholesterol to pregnenolone, catalyzed by cholesterol desmolase (all layers of the adrenal cortex contain it) |
|
|
