2-1-16-Histology Of Pituitary, Hypothalamus, & Pineal (Cole) Flashcards
What are the 2 nuclei of the hypothalamus?
Supraoptic
Paraventricular
This hypothalamic nucleus primarily produces ADH
Supraoptic
This hypothalamic nucleus primarily produces oxytocin:
Paraventricular
The hypothalamus releases ____ which stimulates release of prolactin and thyrotropin (AKA Thyroid Stimulating Hormone)
Thyrotropin-releasing Hormone (TRH)
The hypothalamus releases ___ which stimulates release of FSH and LH
Gonadotropin-releasing hormone (GnRH)
The hypothalamus releases ___ which stimulates release of ACTH
Corticotropin-releasing hormone (CRH)
The hypothalamus releases ___ which stimulates release of GH
Growth hormone releasing hormone (GHRH)
The hypothalamus releases ____ which inhibits release of GH and TSH
Somatostatin
The hypothalamus releases ___ which inhibits release of Prolactin
Prolactin-inhibiting hormone (PIH) AKA Dopamine
The anterior pituitary is stimulated by TRH from the hypothalamus to release ___ which stimulates thyroid production of T3 and T4 thyroid hormones
Prolactin and Thyrotropin (AKA TSH)
The anterior pituitary is stimulated by GnRH from the hypothalamus to release ___ which stimulates follicular development (ovaries) and spermatogenesis (testes). ___ is also released from the anterior pituitary in response to GnRH which stimulates ovulation, estrogen production (ovaries) & testosterone production (testes)
FSH and LH
The anterior pituitary is stimulated by CRH from the hypothalamus to released ___ which stimulates the adrenal cortex to release cortisol
ACTH
Where is the pituitary gland located?
In the SELLA TURCICA within the SPHENOID BONE of the skull. It is posterior to the OPTIC CHIASM
____ is dura mater that extends over and covers the pituitary within the sella turcica
Sellar diaphragm
___ is a pituitary tumor > 1 cm diameter (macroadenoma) present with symptoms due to mass effect.
Nonfunctional pituitary adenoma
Compression of the optic chiasm in nonfunctional pituitary adenoma leads to ___
Bitemporal hemianopsia (issues with peripheral vision)
Compression of the pituitary from nonfunctional pituitary adenoma can lead to ____
Hypopituitarism
In pituitary embryogenesis, ___ becomes anterior pituitary (adenohypophysis) and ___ becomes posterior pituitary (neurohypophysis)
Oral ectoderm
Neuroectoderm
The regressing stalk of Rathke’s pouch can leave residual tissue, which may become a tumor called a _____
Craniopharyngioma
___ is a benign childhood brain tumor that is usually suprasellar. It is similar to pituitary adenomas, can compress the optic chiasm and cause bitemporal hemianopsia.
Craniopharyngioma
A craniopharyngioma is derived from remnant’s of ___; often contains cystic spaces and calcifications
Rathke’s pouch
List the components of the adenohypophysis
Pars distalis (anteior portion)
Pars tuberalis (surrounds infundibular stalk)
Pars intermedia (division between anterior and posterior)
List the components of the neurohypophysis
Pars nervosa
Infundibular stalk
___ is the largest portion of the pituitary gland (75%) and is made up of Glandular epithelial cells, Fenestrated capillaries (sinusoids), and some CT stroma
Pars distalis (pars anterior)
List the Adenohypophysis hormones:
FSH LH ACTH TSH Prolactin GH
FLAT PiG
___ cells of the pars distalis (pars anterior) have granules in the cells that readily take up H&E stain. These cells are divided into acidpohils and basophils
Chromophils (CHroma=color + philein=to love)
___ cells of the pars distalis (pars anterior) do not take up stain and lack affinity. The nuclei are the only visible component and do NOT produce hormones (unknown function)
Chromophobes
____ stain with basic dye (purple/blue and darker with H&E)
____ stain with acidic dye (Pink with H&E)
Basophils
Acidpohils
Gonadotrophs synthesize ____
Corticotrophs synthesize ____
Thyrotrophs synthesize ____
Gonadotropins (FSH, LH)
Adenocorticotropin (ACTH)
Thyrotropin (TSH)
Mammotrophs synthesize ____
Somatotrophs synthesize ____
Prolactin
GH
Gonaotrophs, corticotrophs, and thyrotrophs stain with ____
Mammotrophs and somatotrophs stain with ___
Basic dye
Acidic dye
___ stimulates ovarian follicle maturation and estrogen production in females; it stimulates sertoli cells to produce sperm in males
FSH
FSH can be feedback inhibited by ___
Inhibin and by estrogen in females
___ triggers ovulation and stimulates ovarian production of estrogen and progesterone in females; it promotes Leydig cell production of testosterone in males
LH
LH is feedback inhibited by ___
Estrogen & progesterone in females and testosterone in males
___ stimulates the adrenal cortex to release glucocorticoids and androgens
ACTH
ACTH is feedback inhibited by ___
Glucocorticoids (i.e., cortisol)
___ stimulates thyroid gland to release T3 and T4 –> Control of metabolism
TSH
TSH is feedback inhibited by ___
Thyroid hormones (T3 and T4)
___ stimulates milk production and promotes lactation
Prolactin
Prolactin inhibits GnRH and thus, ___ and ___
FSH
LH
Prolactin is feedback inhibited by ___
PIH –> dopamine
___ indirectly stimulates overall growth of bone and soft tissue via production of Insulin-like growth factors 1 (IGF-1) aka Somatomedin
GH
GH is feedback inhibited by:
- Somatostatin
- Feedback inhibition by GH and IGF-1
- Hyperglycemia, hyperlipidemia, obesity, emotional deprivation
___ is between pars distalis and pars nervosa and has an unknown function. It frequently has a cleft (remnant of Rathke’s) and consists of small basophils and colloid-filled follicles lined by pale cuboidal cells
Pars intermedia
___ suspends the pituitary gland from the hypothalamus
Infundibulum
___ surrounds the infundibular stalks (part of anterior pituitary) and is a component of the infundibulum
Pars tuberalis
___ is the neural portion of the infundibulum and is part of the posterior pituitary
Infundibular stalk
___ is a thin neural stalk connecting the median eminence of the hypothalamus to the pars nervosa
Infundibular stalk
What are the 2 parts of the infundibular stalk?
Median eminence and Infundibular process
What are the neurohypophysis hormones?
ADH and Oxytocin
___ of the pars nervosa are glial-like cells and appear to support numerous unmyelinated nerve fibers traveling from the hypothalamus
Pituicytes
___ of the pars nervosa are expanded axon terminals filled with the stored neurohypophysis hormones (ADH and oxytocin)
Herring bodies
____ is primarily produced by the supraoptic nucleus in the hypothalamus and regulates serum osmolarity (via V2-receptors in DCT and CD –> causes water retention and concentrates urine. It is also a potent vasoconstrictor at high doses (via V1-receptors)
ADH
ADH release is regulated by ___
Hypothalamic osmoreceptors and baroreceptors
___ is primarily produced by paraventricular nucleus of the hypothalamus and functions to contract smooth muscle, i.e., uterine contractions during labor & after to contract uterus back down to normal size as well as facilitate milk ejection via breast myoepithelial cells
Oxytocin –> “Feel good hormone”
Pituitary blood supply is via ___ artery
Internal carotid
___ arteries are off of the internal carotid artery and supply median eminence and infundibulum
___ arteries are off of the internal carotid arterty and supply the pars nervosa
Superior hypophyseal
Inferior hypophyseal
Superior hypophyseal arteries give rise to the ___ which collects hypothalamic releasing and inhibitory hormones
Primary capillary plexus
The primary capillary plexus is drained by ___ veins and delivers blood into the secondary capillary plexus (in pars distalis). These collect anterior pituitary secretions and sends them into circulation via fenestrated capillaries
Hypophyseal portal
Inferior hypophyseal arteries give rise to the ___ which supplies and collects hormones from posterior pituitary (ADH and oxytocin) and sends them into circulation via their own hypophyseal veins
3rd capillary plexus
Outline the venous drainage of the anterior pituitary gland secreting hormones:
Anterior pituitary gland secretes hormones –> diffuse into capillaries –> venous sinuses (petrosal and cavernous)
Outline the venous drainage of the posterior pituitary secreting hormones:
Posterior pituitary gland secretes hormones –> diffuse into capillaries –> hypophyseal veins –> venous sinuses (petrosal and cavernous)
The pineal glands develops from a posterior outpocketing of the roof of the ____
Diencephalon in midline of 3rd ventricle
___ main functions are to manufacture melatonin and serotonin
Pineal gland
The pineal gland does not have a direct nerve connection to the brain. Rather, it is regulated postganglionic sympathetics from ___
Superior cervical ganglion
The pineal gland contains a capsule derive from ___ and is made up of pinealocytes, neuroglial cells, calcified granular material (brain sand), and contains NO NEURONS
Pia mater
___ are neuron-like, have large, pale, irregular nuclei, are regulated by B-adrenergic receptors, and their main function is production of melatonin and serotonin
Pinealocytes
___ are interstitial cells, have smaller and dense nuclei, and support pinealocytes
Neuroglial cells
Melatonin is synthesized from this AA:
Tryptophan
Melatonin acts to delay sexual development until puberty by inhibiting __ and __ secretion
GnRH
GH
When puberty arrives, melatonin production will ___
Decrease
Pineal tumors are linked to ___
Precocious puberty (Decreases melatonin –> early sexual maturity)
Melatonin can be used for treatment of:
Jet lag –> disrupted circadian rhythm
Seasonal affective disorder –> help regulate emotional responses due to decreased daylight during winter
Insomnia
Where is the location of the hypothalamus?
Floor of the DIENCEPHALON
Forms part of the wall of the 3rd ventricle
___ is characterized by a delayed/absent puberty and anosmia (no sense of smell), hypogonadotrophic hypogonadism, and prevents migration of GnRH neurons to arcuate nucleus and olfactory neurons to olfactory bulb
Kallman syndrome
___ is due to loss of feedback control of GH secretion or to GH-secreting tumor in the pituitary (adenoma)
Pituitary gigantism
___ is due to an excessive adult production of GH. It is characterized by growth of the face (prognathism), hands and feet, and increase in viscera and is due to loss of feedback control of GH secretion or to GH-secreting tumor in the pituitary.
Acromegaly
___ is growth retardation resulting in abnormally short adult stature. It is caused by a variety of hereditary and metabolic disorders.
Pituitary dwarfism–> caused by insufficient GH
Problem can be in hypothalamus or pituitary
