01c: Hypothalamus-Pituitary Axis Flashcards
List the hormones secreted by the posterior pituitary, formally called the (X).
X = neurohypophysis
ADH and oxytocin
The infundibular stalk is part of (neuro/adeno)-hypophysis and is directly connected to pars (X).
Neurohypophysis;
X = nervosa
(Ant/post) to pars nervosa are the pars (X) and pars (Y). Star the one(s) belonging to adenohypophysis.
Ant;
X = intermedia*
Y = distalis*
Surrounding the infundibulum is the pars (X), which is part of (neuro/adeno)-hypophysis.
X = tuberalis;
Adenohypophysis
The pituitary develops embryonically from which two different (ecto/endo)-dermal regions?
Ectodermal;
Roof of mouth and floor of brian
The infundibulum is connected to the brain by a small elevation called:
the median eminance
Neurohypophysis forms embryonically from which region of (ecto/endo)-derm?
Ectoderm;
Floor of brain
Adenohypophysis forms embryonically from which region of (ecto/endo)-derm?
Ectoderm;
Roof of mouth
The capillary plexus in the post pit is supplied by which artery(ies)?
Inferior hypophyseal
(X) is the stimulus for post pit to release contents of neurosecretory granules, which are stored in (Y).
X = nerve impulses (from hypothalamus) Y = nerve terminals
T/F: In post pit, a simple pair of cells performs hormone synthesis, storage, and release.
False - a SINGLE cell does all that (cell body in hypo, axon terminals in post pit)
Stimuli that regulate ant pit secretion comes directly from (neurons/blood).
Blood-borne stimuli (synthesized in hypo)
Hypothalamic neurons synthesize (releasing/inhibiting) hormones that control ant pit. They are stored in (X), near (Y).
Both;
X = Median eminance
Y = superior hypophyseal artery’s capillary plexus
Stimulating/inhibiting hormones to ant pit are released into (X), travel via (Y), and exit from (Z) to reach their specific target cells.
X = first capillary plexus (from superior hypophyseal a) Y = portal vein Z = secondary cap plexus
T/F: The ant pit secretes its hormones into the same cap plexus that its stim/inhib factors come from.
True
ADH originates primarily in (X) nuclei and its target cells are (Y).
X = supraoptic; Y = renal
(Excess/deficiency) of (X) pituitary hormone leads to diabetes insipidus.
Deficiency;
X = ADH
Oxytocin originates primarily in (X) nuclei and its primary role is to (Y) via which mechanism?
X = paraventricular Y = eject milk from lactating mammary glands
Contraction of myoepithelial cells of gland
Suckling by infant is detected by (X) receptors and is the major stimulus for (Y) hormone release.
X = nipple's sensory Y = oxytocin
(X) hormone has powerful action on (smooth/skeletal) muscle of uterus during labor. The primary stimulus for (X) release is (Y) and (X) enhances uterine (relaxation/contraction).
X = oxytocin;
Smooth;
Y = dilation of cervix
Contraction
T/F: Oxytocin effect on uterine contraction is example of positive-feedback loop.
True
Low ADH levels is sensed by (X) receptors of (Y) cells that then connect to ADH nerve cells.
X = osmo- Y = neurons
(X) is the most abundant of the pituitary hormones, with normal plasma basal concentration of (Y).
X = Growth Hormone; Y = 5 ng/mL
T/F: All actions of growth hormone are insulin-like.
False - depends on tissue
The growth-promoting actions of GH on (X) tissues are (similar/opposite) to insulin.
X = muscle and skeleton
Similar
The long-term actions of GH on (X) processes are (similar/opposite) to insulin.
X = CHO, lipid, AA metabolism
Opposite
The two key cell types targeted by GH are (X) and (Y). Star the one that releases somatomedins, i.e. (Z).
X = chondrocytes Y = hepatocytes* Z = IGF-I
(X) hormone, released by (Y), is the major hormone responsible for lactogenesis.
X = prolactin Y = ant pit
Specifically, prolactin (stimulates/inhibits) synthesis of (X) in (Y).
X = casein and lactalbumin Y = mammary glands
Thanks to (X), (GH/prolactin) is tonically (stimulated/inhibited).
X = dopamine
Prolactin;
Inhibited
T/F: Stress and exercise are associated with decreased circulating prolactin levels.
False - increased
(GH/Prolactin) regulates a secondary endocrine gland. Receptors for (GH/Prolactin) are found in (X) endocrine gland.
Neither;
Both;
X = adrenal cortex
T/F: In supportive role with estrogen, prolactin stimulates breast development.
True
Galactorrhea, aka (X), is indicative of (excess/deficiency) in (Y) hormone.
X = milk discharge from nipple
Excess;
Y = prolactin
(Excess/deficiency) in prolactin levels leads to suppression of ovulation. What’s the mechanism of this?
Excess;
Inhibits GnRH secretion
(X) are the pituitary glycoprotein hormones, which share common (Y) structure of (2/4/6) subunits.
X = FSH, LH, TSH
Y = quaternary
2 (alpha and beta)
Pro-opiomelanocortin (POMC) is a precursor released from (X). Which two key hormones are derived from POMC?
X = ant pit
- ACTH
- Beta-lipotropin
Key function of ACTH.
Stimulates adrenal steroidogenesis
Key function of beta-lipotropin hormone.
Stimulates melanin synthesis in melanocytes
TSH stimulates (X) cells to carry out which function(s)?
X = thyroid
Trap iodide, synthesize and secrete thyroid hormones
Prolactin is unique among those of the anterior pituitary because:
Its secretion increases (rather than decreases) when vascular connection between pit and hypo is interrupted (DA doesn’t inhibit)
T/F: Secretion of some ant pit hormones are influenced by more than one hypothalamic releasing hormones.
True (i.e. GH and prolactin)
Gonadotropin Releasing Hormone (GnRH) is also called (X). It’s released by (Y) and functions to:
X = LHRH Y = hypothalamus
Stimulate LH and FSH secretion
Growth Hormone Releasing Hormone (GHRH) is released from (X) and functions to (Y).
X = hypothalamus Y = stimulate GH synthesis/release from ant pituitary
Somatostatin is released from (Hypo/Ant Pit) and functions to (X).
Hypothalamus;
X = inhibit GH synthesis/release from ant pituitary
(also called GHIH)
T/F: GHRH and Somatostatin are only released from the hypothalamus.
False - somatostatin also released from D-cells
Thyrotropin Released Hormone (TRH) is released from (X) and functions to (Y).
X = hypothalamus Y = stimulate synthesis/secretion of thyroid stimulating hormone (TSH) and prolactin
Prolactin Inhibiting Factor (PIF) is released from (X) and functions to (Y).
X = hypothalamus Y = tonically inhibit prolactin secretion
*likely the NT dopamine
Corticotropin Releasing Hormone (CRH) is released from (X) and functions to (Y).
X = hypothalamus Y = stimulate ACTH synthesis/release from ant pit
Long-loop negative feed back refers to the phenomenon when (X) has (stimulatory/inhibitory) effect on:
X = hormone 3 (released from peripheral gland)
Inhibitory;
- Pituitary (making it less responsive to releasing factor from hypo)
- Hypothalamus (reduce AP frequency)
Short-loop negative feed back refers to the phenomenon when (X) has (stimulatory/inhibitory) effect on:
X = hormone 2 (released from anterior pituitary)
Inhibitory;
Hypothalamus
List the 3 major categories of endocrine disorders.
- Hyposecretion
- Hypersecretion
- Hypo-responsiveness
A dysfunctional endocrine gland secreting too much hormone is example of (primary/secondary) (X) category of endocrine disorders.
Primary;
X = hypersecretion
A functional endocrine gland receiving too little tropic hormone from (X) is example of (primary/secondary) (Y) category of endocrine disorders.
X = pituitary
Secondary;
Y = hyposecretion
Categorize the endocrine disorder: Testosterone secreted normally with normal receptors on target cells. Lack of enzyme (5-a-reductase) to metabolize testosterone.
Hypo-responsiveness category; specifically, lack of metabolic activation of hormone
Categorize the endocrine disorder: Insulin produced normally, but few insulin receptors exist.
Hypo-responsiveness category; specifically, lack/deficiency of receptors for the hormone
Categorize the endocrine disorder: Hyposecretion of TH due to low TSH by pituitary.
Secondary hyposecretion
Categorize the endocrine disorder: Tumor of thyroid gland secretes too much (X).
X = TH;
Primary hypersecretion
Categorize the endocrine disorder: normal receptor, but (when activated) can’t form cAMP second messenger.
Hypo-responsiveness; specifically, post-receptor defect in target cell
