L70: Hypothalamic-Pituitary Relationship Flashcards
What artery supplies the portal system of the anterior pituitary?
Superior hypophyseal artery
Hypothalamic releasing factors all target
anterior pituitary
What brain nucleus is dopamine synthesized in?
Arcuate nucleus
Table of hypothalamic releasing hormones…
See table
Bonus: how many peptides long is GnRH
10aa’s! It is HIGHLY CONSERVED among vertebrates.
Bonus: how many peptides long is TSH?
3aa’s only!
What kind of receptor binds GnRH?
GPCR
GnRH neurons fail to cross cribriform plate into CNS during development
Kallman’s syndrome
Pulsatility of GnRH mirrors pulsatility of
LH release
When GnRH pulse rate decreases, what happens to LH and FSH secretion?
LH decreases, FSH increases
The hypothalamic releasing hormone regulates WHAT SUBUNIT of a pituitary glycoprotein hormone?
B-subunit varies and is regulated. Alpha-unit is conserved.
GnRH binds GPCR in a pulsatile manner. Does this promote the synthesis of hormones, or the release of hormones?
Both!
IP3/Ca2+ pathway: promotes hormone release
DAG/PKC pathway: promotes hormone synthesis
The pulsatility of GnRH is significant because
A. It maximizes the availability of the receptor
B. Promotes differential release of hormones
C. Promotes differential synthesis of hormones
D. All of the above
D. All of the above
Neurohypophysial tract
Neurons whose axons terminate in the posterior pituitary
Which send axons to the median eminence, into capillary system?
A. Tuberoinfundibular system
B. Neurohypophysial tract
A.
Histologically, posterior pituitary tissue is derived from
Neural tissue derived from neuroectoderm
Histologically, the anterior pituitary is derived from
Glandular tissue (epithelial cells) from embryonic foregut (endoderm just fyi)
This is the pituitary. The dark cells above are
Glandular, thus anterior pituitary (pars distalis)
This is the pituitary. The lighter cells below are
Neural. Posterior pituitary (pars nervosa)
What are magnocellular neurosecretory cells?
Cell bodies of the posterior pituitary located in the hypothalamus, that secrete OT, NP, and AVP into the post. pit. capillary bed
What is the blood supply for the post. pit?
A. Inf. hypophysial a.
B. Sup. hypophysial a.
A. INFERIOR hypophysial a.
What are the darkly (purple) stained cells here?
Pituicytes - the glial cells of the post. pit
What are these red stained bodies?
Herring bodies - unmyelinated axon terminals in the posterior pituitary, that originated in magnocellular neurosecretory cells from the neurohypophysis.
What’s another word for the anterior pituitary?
Adenohypophysis
What is the interface for all hypophysiotrophic hormones?
Median eminence.
Lies outside the BBB and forms the floor of 3rd ventricle.
Dopamine promotes milk production or ejection?
Production. Oxytosin promotes milk ejection
GnRH. What brain nuclei?
POA mostly
CRH. What brain nuclei?
PVN (parvocellular)
TRH. What brain nuclei?
PVN
GHRH. What brain nucleus?
Arcuate nucleus.
(think of a giant doing pullups on the St. Louis Arch)
Somatostatin
Periventricular nucleus (PeVN) not paraventricular
(think of Katy PERI STOPPING the half-time show)
Dopamine. What brain nucleus?
Arcuate nucleus
(the giant doing pullups on the St. Louis Arch is high on DOPE)
Hormone RELEASE. Is this IP3/Ca2+ or DAG/PKC?
IP3/Ca2+
What part of FLAT PiG is basophiles?
FLAT
What part of FLAT PiG is acidophiles?
PiG
Which are the most numerous cell type in anterior pituitary?
Acidophiles (prolactin and GH secreting)
Whats a parvicellular neuron
Terminates on median eminence, releasing FLAT PiG
What is a magnocellular neuron
Terminates in neurohypophysis (posterior pituitary) releasing AVP and OT
What catecholamine suppresses the release of prolactin?
Dopamine
What catecholamine suppresses the SYNTHESIS of milk?
Dopamine inhibits prolactin, which promotes milk synthesis
What 3 parts compose the anterior pituitary?
Pars distalis (90%)
Pars intermedia
Pars tuberalis
What are the anatomical parts of the posterior pituitary?
Pars nervosa
Infundibulum (stalk)
