Histology Of The Pituitary, Hypothalamus, And Pineal Flashcards
What is the location of the hypothalamus?
- Floor of the diecephalon
- Forms part of the wall of the 3rd ventricle
What two hormones does the hypothalamus produce and where are they stored?
Oxytocin and ADH
Posterior pituitary
What nuclei PRIMARILY makes ADH?
Supraoptic
What nuclei PRIMARILY makes oxytocin?
Paraventricular
What hormone released from the hypothalamus inhibits the release of GH and TSH?
Somatostatin
What hormone released from the hypothalamus inhibits the release of prolactin?
Prolactin-inhibiting hormone (PIH or Dopamine)
Location of the pituitary gland?
In the Sella Turcica within the sphenoid bone of the skull
Posterior to the optic chiasm
A pituitary tumor greater than 1 cm can present with what?
- bitemporal hemianopsia (problems with peripheral vision)
- Hypopituitarism
- headache
What develops into the adenohypophysis (anterior pituitary)?
Oral ectoderm
What develops into the neurohypophysis (posterior pituitary)?
Neuroectoderm
Endocrine cells are always very close to what?
Fenestrated capillaries
What is the outgrowth of the roof of the mouth called before is buds off to from the anterior pituitary?
Rathke’s pouch
The regressing stalk of Rathke’s pouch can leave residual tissue which may become a tumor called a what?
Craniopharyngioma
A Craniopharyngioma is usually BENIGN but causes problems due to mass effect and also often contains what 2 things?
- cystic spaces
- calcifications
What are the 3 regions of the Adenohypophysis?
- Pars Distalis
- Pars tuberalis
- Pars intermedia
Anterior portion of the adenohypophysis is what?
Pars Distalis (largest portion)
Portion of the adenohypophysis that surrounds the infundubular stalk?
Pars tuberalis
Portion of adenohypophysis that divides the anterior and posterior
Pars intermedia
2 regions of the neurohypophysis
- Pars nervosa (bulk of it)
- Infundibular stalk
6 hormones produced by Pars Distalis?
F: FSH L: LH A: ACTH T: TSH P: Prolactin I G: GH
FLAT PiG
2 Major groups of cells in the Pars Distalis?
- Chromophils (readily takes of H&E stain)
- Chromophobes (doesn’t take up stain)
What are the two types of Chromophils?
- Acidophils (Acid loving - takes up eosin=pink)
_Basophils (basic loving - takes up hematoxylin=purple/blue)
What 4 hormones to basophils produce?
- Gonadotrophs (FSH and LH)
- Corticotrophs (ACTH)
Thyrotrophs (TSH)
FLAT
What hormones do Acidophils produce?
- Mammotrophs (Prolactin)
- Somatotrophs (GH)
PiG = Pink
Name the Hormone: stimulates ovarian follicle maturation and estrogen production in females; stimulates Sertoli cells to produce sperm in males.
FSH
What is FSH inhibited by?
Estrogen in females
Inhibin in males
Names the hormone: Triggers ovulation and ovarian production of estrogen and progesterone in females; Promotes Leydig cell production of testosterone in males.
LH
- Delayed/Absent puberty and anomia (no sense of smell)
- Hypogonadotrophic hypogonadism
- genetic mutation
- Prevents migration of GnRH neurons to arcuate nucleus and olfactory neurons to olfactory bulb
Kallman Syndrome
Name the hormone: stimulated by CRH in circadian manner; stimulates the adrenal cortex to release glucocorticoids and androgen
ACTH
What is ACTH inhibited by?
Feedback inhibition by glucocorticoids (cortisol)
Name the hormone: stimulates thyroid gland to release T3 and T4 –> control metabolism
TSH
What inhibits TSH?
Feedback inhibitions by T3 and T4
Name the hormone: Stimulates milk production and promotes lactation; Inhibits GnRH and thus FSH and LH
Prolactin
What enhances decreased PIH and thus stimulates prolactin production?
- Estrogens
- Birth control
- Breast Feeding
- dopamine antagonist drugs
Name the hormone: Indirectly stimulates overall growth of bone and soft tissue via production of insulin-like growth factor-1 (IGF-1) aka somatomedin; Pulsatile secretion, greatest in 1st 2 hours of sleep
GH
Name the hormone: inhibited by hyperglycemia, hyperlipidemia, obesity, emotional deprivation
GH
Name it hormone: stimulated by hypoglycemia, low levels of FA’s, high blood levels of aa’s, and exercise
GH
Name the disorder: Loss of feedback control of growth hormone secretion or the GH secreting tumor in pituitary
Pituitary gigantism
Name the disorder: Excessive ADULT production of growth hormone; growth of face, hands, and feet; increase in viscera; overproduction of glucose leads to diabetes
Acromegaly
Name the disorder: Growth retardation resulting in abnormally short adult stature; caused by hereditary or metabolic; insufficient growth hormone; problem can be in hypothalamus or pituitary;
Pituitary dwarfism
Non-pituitary dwarfism is caused by what?
Inadequate nutrition early in life
Region of the adenohypophysis that in other animals synthesizes proopiomelanocortin so it changes skin color
Pars intermedia
Glial like Cells of the Pars Nervosa that appear to support numerous unmyelinated nerve fibers traveling from the hypothalamus
Pituicytes
Expanded axon terminals in the Pars Nervosa that are filled with stored secretory granules that contain, ADH, and Oxytocin and neurophysin carries
Herring bodies
What is the release of ADH regulated by?
Hypothalamic osmoreceptors and Baroreceptors
What does ADH regulate
Serum osmolarity
What artery supplies blood supply to the pituitary?
Internal carotid
What supplies Pars Nervosa with blood
Inferior hypophyseal arteries
What supplies median eminence and infundibulum with blood?
Superior hypophyseal artery
Neuronoendocrine transducer that handling photic information from the retina happens where?
Pineal gland
Plays a role in growth, development, and regulation of circadian rhythms
Pineal gland
Main functions are to manufacture melatonin and serotonin
Pineal gland
What is the pineal gland regulated by?
Post ganglionic sympathetics from superior cervical ganglion
Histological characteristic of pineal gland
- Calcified granular material (“brain sand”)
- NO neurons
Melatonin is synthesized from what?
Tryptophan
Pineal tumors are linked to what?
Precocious (premature) puberty
