Hypothalamus Slides
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Transcript of Hypothalamus Slides
MPBP 301: ENDOCRINOLOGYHYPOTHALAMUS / PITUITARY
IMAGING MODULE: Head & Neck I
= PITUITARY
= HYPOTHALAMUS
MRI
OBJECTIVES: HYPOTHALAMUS / PITUITARY
Describe the embryologic origins of the neuro- and adenohypophysis.
Describe the location of the pituitary and some of the clinical implications of that location.
Define the hormone products of the hypothalamus and list their target(s).
Define the hormone products of the neurohypophysis and list their targets.
Define the hormone products of the adenohypophysis and list their targets.
Draw and identify the key components of the control system for endocrine systems regulated through the adenohypophysis.
Describe the role of releasing hormones in control of hypothalamic-adenohypophyseal feedback systems.
Describe the role of tropic hormones in control of hypothalamic-adenohypophyseal feedback systems.
Describe the mechanism by which circulating hormones exert their negative feedback effect on the adenohypophysis.
(WHEATER)
EMBRYOLOGY INSTRUCTS
X-RAY
IMAGING MODULE: Head & Neck I
MRI
MRI
NERVESBLOOD
NEUROHYPOPHYSIS
AntiDiuretic Hormone (ADH) / Vasopressin
Oxytocin
GROWTH HORMONETHYROID HORMONECORTISOL(REPRODUCTIVE SYSTEM)
ADENOHYPOPHYSIS
RELEASINGHORMONES
TROPHICHORMONES
HYPOTHALAMIC – PITUITARYREGULATION: ADENOHYPOPHYSIS
SETPOINT:CNS / HYPOTHALAMUS
FEEDBACK:PITUITARY
THE KEY ELEMENTS(What you need to know)
Chromophils of the Anterior Pituitary
• Acidophils:• Somatotrophs: Growth Hormone• Lactotrophs Prolactin• Basophils: • Gonadotrophs: Follicle Stimulating
hormone, LH• Thyrotrophs: TSH• Corticotrophs: ACTH
Somatotrophs are the major cell type 50%; Lactotrophs, 20%; Gonadotrophs, 5%; Thyrotrophs 5%, Corticotrophs, 20%
THE TROPICHORMONES
THE RELEASING HORMONES
TRH in the PV NUCLEUS
RELEASING HORMONES ARENOT MONOSPECIFIC*
TRH causes Prolactin ReleaseGnRH is same for FSH and LHGHRIH (ST) inhibits TSH releaseGHRIH (ST) regulates endocrine pancreasCRH regulates parturition
*Know Concept not facts
CNS REGULATION
THE SAME NEUROTRANSMITTERSAS ELSEWHERE IN THE CNS
COMPLICATES USE OF NEUROTRANSMITTERSTHERAPUTICALLY
WHAT ELSE DO RELEASING HORMONES DO?
MANY THINGS:
OVERALL CNS FUNCTION: BEHAVIORGASTROINTESTINAL SYSTEMENDOCRINE PANCREASPARTURITIONETC.
CONCEPT: I WILL NOT ASK
FEEDBACK ON PITUITARYREGULATION OF RH RECEPTORS
KEY CONCEPT
RTRH
TRH
PITUITARY FEEDBACK: NORMAL vs HIGH FEEDBACK
TSH
TRH TRH
RTRH
TRH TRH TRH
RTRH RTRH
+ + + +
T3 T3
__AP Cell AP Cell
TSH
NORMAL ELEVATED T3
TRHTRH
TRHTRH
TRH = Thyrotrophic Releasing HormoneTSH = Thyroid Stimulating HormoneT3 = Thyroid Hormone
RTRH RTRH
++
PITUITARY FEEDBACK: NORMAL vs HIGH FEEDBACK
TRH = Thyrotrophic Releasing HormoneTSH = Thyroid Stimulating HormoneT3 = Thyroid Hormone
RTRH
TRH
TSH
TRH TRH
RTRH RTRH
+ + +
T3
_AP Cell
ELEVATED T3
TRHTRH
RTRH RTRH
RTRH
TRH
TSH
TRH TRH
RTRH RTRH
+ + +
T3
_AP Cell
NORMAL
TRHTRH
RTRH RTRH
+ +
FIRST: T3ELEVATED
RTRH
TRHPITUITARY FEEDBACK: NORMAL vs HIGH FEEDBACK
TSH
TRH TRH
RTRH
TRH TRH TRH
RTRH RTRH
+ + + +
T3 T3
__AP Cell AP Cell
NORMAL ELEVATED T3
TRHTRH
TRHTRH
TRH = Thyrotrophic Releasing HormoneTSH = Thyroid Stimulating HormoneT3 = Thyroid Hormone
RTRH RTRH
TSH
++
SECOND: LOSS OFTRH RECEPTORS
RTRH
TRHPITUITARY FEEDBACK: NORMAL vs HIGH FEEDBACK
TSH
TRH TRH
RTRH
TRH TRH TRH
RTRH RTRH
+ + + +
T3 T3
__AP Cell AP Cell
TSH
NORMAL ELEVATED T3
TRHTRH
TRHTRH
TRH = Thyrotrophic Releasing HormoneTSH = Thyroid Stimulating HormoneT3 = Thyroid Hormone
RTRH RTRH
++
THIRD: TSH SIGNALREDUCED
RTRH
TRHPITUITARY FEEDBACK: NORMAL vs HIGH FEEDBACK
TSH
TRH TRH
RTRH
TRH TRH TRH
RTRH RTRH
+ + + +
T3 T3
__AP Cell AP Cell
TSH
NORMAL ELEVATED T3
TRHTRH
TRHTRH
TRH = Thyrotrophic Releasing HormoneTSH = Thyroid Stimulating HormoneT3 = Thyroid Hormone
RTRH RTRH
+_
FOURTH: THYROIDSHUTS DOWN
RTRH
TRH
TSH
TRH TRH
RTRH
TRH TRH TRH
RTRH RTRH
+ + + +
T3T3
__AP Cell AP Cell
TSH
NORMAL REDUCED T3
RTRH
RTRH
RTRH
RTRH
TRH TRH
TRHTRH
RTRH
RTRH
RTRH
RTRH
++
++
TRH = Thyrotrophic Releasing HormoneTSH = Thyroid Stimulating HormoneT3 = Thyroid Hormone
PITUITARY FEEDBACK: NORMAL vs LOW FEEDBACK
++
A CRITICAL FUNCTION TEST
A LOOK AHEAD
THYROID FEEDBACK MODULE
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