Hypothalamus, Pituitary & Pineal Flashcards by Maggie Eby

(Endocrine system) Communicates via ______, secretory products
of endocrine cells, carried by bloodstream to target tissue containing
receptors

chemical messengers (hormones)

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(Endocrine system) Communicates via chemical messengers (hormones), secretory products
of endocrine cells, carried by bloodstream to ______

target tissue containing
receptors

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(Endocrine system) Endocrine organs composed of secretory cells of _____ origin

epithelial

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(Endocrine system)
Lack ducts & secrete hormones into bloodstream
* Possess rich blood supply with ______ networks to absorb
& transport hormones.

fenestrated capillary

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(Endocrine system)
_____ onset & ____ duration than nervous control
* Endocrine organs integrate function of physiologic systems

Slower onset & longer duration

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Most ______ glands form discreet organs (Anterior pituitary, pineal, thyroid
and suprarenal (adrenal); in pancreas, endocrine & exocrine tissue intermixed

endocrine

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____ coordinates endocrine functions of body—acts as
intermediary between autonomic nervous system & endocrine system

Hypothalamus

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Suspended by a stalk from
hypothalamus

Pituitary
(Hypophysis)

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(Pituitary) Rests in ____ of the
sphenoid bone, posterior to
the optic chiasm (CN II)

sella turcica

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Two major divisions of Pituitary:

Adenohypophysis
(Anterior pituitary)
Neurohypophysis
(Posterior pituitary)

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Secretion of ____ hormones
controlled by hypothalamus, with
complex blood supply

pituitary

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pituitary gland–Includes _____, which allows
communication with hypothalamus

hypophyseal portal
system

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Hypothalamus controls secretion of
______ via hypothalamic
regulating factors (hormones)

anterior pituitary

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_____ stimulate
secretion; _____
inhibit secretion

Releasing factors; inhibitory factors

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_____ hormones—have non-endocrine target organ
(e.g., GH, ADH, MSH, oxytocin, prolactin)

Direct acting hormones

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_____ hormones—target organ is another endocrine gland
(e.g., TSH, ACTH, FSH, LH)

Trophic hormones

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Thyroid gland, adrenal cortex, & gonads all ____-
dependent endocrine glands

pituitary

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Pituitary hormones: Functionally, anatomically, & embryologically, pituitary
divided into ___ portions

anterior & posterior

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(Pituitary) Anterior portion contains ______ tissue &
posterior contains_____ tissue

glandular epithelial tissue; neural secretory tissue

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(anterior pituitary) “Master gland”

(=adenohypophysis = pars
anterior = pars distalis)

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(ant pituitary) Specialized glandular tissue, arises from
evagination of tissue from oral cavity in
region of pharynx called _____

Rathke’s pouch

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Rathke’s pouch differentiates into 3 distinct
regions of anterior pituitary:

pars distalis, pars intermedia, pars tuberalis

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—bulk of anterior pituitary

pars distalis

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—thin layer between anterior
& posterior pituitary
Secretes MSH & ACTH
Frequently contains cystic remnants of
Rathke’s pouch

pars intermedia

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—extension of anterior pituitary; forms collar ~pituitary stalk (=infundibulum)

pars tuberalis

Pars distalis secretes bulk of pituitary hormones, including both direct acting & ____ hormones

trophic

(Pars distalis) Direct acting hormones—____ * Trophic hormones—

GH & prolactin; TSH, ACTH, FSH, LH

Secretory cells of anterior pituitary traditionally classified as ___ or ____

chromophils (which stain) or chromophobes (do not stain) -- Cells now classified by hormone content

2 types of chromophils:

Acidophils & Basophils

—stain with acidic dye; pink on H&E (chromophils)

Acidophils

—stain with basic dye; pale blue to light purple on H&E (chromophils)

* Basophils

—small cells, don’t take up either dye, clear on H&E; represent inactive cells

Chromophobes

Acidophils: * ______— ~50% of cells; secrete Growth Hormone (GH or somatotropin). Releasing: GHRH; Inhibiting: Somatostatin (GHIH). Stimulating: ghrelin (stomach enteroendocrine cells) coordinates food intake with GH secretion

Somatotrophs

— (= lactotrophs) ~20% of cells; secrete prolactin (controls lactation). Releasing: PRH; Inhibiting: dopamine

Mammotrophs

(controls lactation).

prolactin

(Cell subtypes) Basophils:

Thyrotrophs, Gonadotrophs, corticotrophs

— ~5% of cells; secrete Thyroid Stimulating Hormone (= thyrotropin)

Thyrotrophs

— ~5% of cells; secrete Follicle Stimulating Hormone (FSH) & Lutenizing Hormone (LH)

Gonadotrophs

— ~20% of cells; secrete Adrenocorticotropic hormone (ACTH), Melanocyte-stimulating hormone (MSH), endorphins

Corticotrophs

- excessive production of growth hormone beginning in childhood

Pituitary gigantism

(Pituitary gigantism) Due to loss of feedback control of _______ or to GH-secreting tumor in pituitary (adenoma

growth hormone secretion

Skeletal growth as well as internal organs * Significant problems with blood glucose management * Death usually due to heart disease or diabetes (complications)

Pituitary gigantism

Excessive adult production of growth hormone * Growth of face (prognathism), hands & feet

Acromegaly

Increase in viscera * Overproduction of glucose leads to diabetes * ?Due to loss of feedback control of growth hormone secretion or to GH-secreting tumor in pituitary * Tx: surgery, radiation, growth hormone receptor antagonist

Acromegaly

--Growth retardation resulting in abnormally short adult stature. --Problem can be in hypothalamus or pituitary --“Tx” – injections of growth hormone

Pituitary Dwarfism

(Pituitary Dwarfism--Growth retardation ) --It is caused by a variety of hereditary and metabolic disorders. --Pituitary dwarfism is caused by _____

insufficient growth hormone.

(Pituitary Dwarfism--Growth retardation ) --It is caused by a variety of: ____ disorders

variety of hereditary and metabolic disorders.

(Pituitary Dwarfism) Growth _____ resulting in abnormally short adult stature.

growth retardation

_____ stimulates initiation & maintenance of milk production postpartum

Prolactin

(prolactin) Secretion is mediated primarily by inhibition control mediated by ____

dopamine

(prolactin) Secretion is stimulated by _____ but suckling during lactation is the primary stimulus.

PRH

As birth control: Prolactin inhibits the pulsatile secretion of _____ which suppresses secretion of FSH & LH.

GnRH

As birth control: Prolactin inhibits the pulsatile secretion of GnRH which suppresses secretion of ____

FSH & LH.

This tumor can grow superiorly and impinge on the optic chiasm producing visual field defects (classically: bitemporal hemianopsia) * The tumor can also erode the sella turcica * A tumor large like this will produce also increased intracranial pressure (with headache, nausea, and vomiting).

Pituitary macroadenoma

Pituitary macroadenoma: This tumor can grow superiorly and impinge on the ____

optic chiasm

Pituitary macroadenoma: This tumor can also erode the ___

sella turcica

(Pituitary macroadenoma) bitemporal hemianopsia

tunnel vision

Produce adrenocorticotropic hormone (ACTH) and lipotropic hormone (LPH)

Corticotrophs

ACTH stimulates hormone release by the ____

adrenal (suprarenal) cortex

LPH stimulates ______; precise role in humans in unknown

lipid mobilization in some mammals

Produce follicle-stimulating hormone (FSH) and luteinizing hormone (LH)

Gonadotrophs

- stimulates ovarian follicle development/estrogen secretion or production of androgen binding protein by Sertoli cells.

FSH

- helps control the menstrual cycle. It also triggers the release of an egg

Produce thyroid stimulating hormone (TSH) or thyrotropin *Stimulates thyroid gland to synthesize, store & release thyroid hormones

Thyrotrophs

*Stimulates thyroid gland to synthesize, store & release thyroid hormones

thyroid stimulating hormone (TSH) or thyrotropin

Releasing: TRH *Inhibiting: negative feedback suppression by CNS based on amount of circulating thyroid hormones

Cells containing no secretory granules undifferentiated (stem) cells or folliculostellate cells - stroma to support chromophils

Chromophobes

(chromophobes) Cells containing no secretory granules ______ cells or _____ cells - stroma to support chromophils

undifferentiated (stem); folliculostellate

Chromophobes: Cells with granules - partially _____ chromophils

degranulated

______ --> 2o plexus in pars distalis

Portal veins

Tubular sheath that extends from the pars distalis and winds around the pituitary stalk.

Pars tuberalis

Epithelial cells (gonadotrophs) arranged in cords and hypophyseal portal vessels are found here.

Pars tuberalis

(Pars tuberalis) Epithelial cells (gonadotrophs) arranged in ____ and ____ vessels are found here.

cords; hypophyseal portal vessels

Pars Intermedia: Synthesize ______

proopiomelanocortin

Cords of basophilic cells Colloid-filled follicles

Pars Intermedia:

Pars Intermedia: alpha- and -melanocyte- stimulating hormone which stimulates ______ production

melanin (pigment)

melanin (pigment) secretion causes a dramatic darkening of the skin of fishes, amphibians, and reptiles as granules of melanin spread through the branches of specialized melanocytes called ______

melanophores.

T/F: Diseases that may be attributed to the under- or oversecretion of MSH are not well defined in humans.

true

NEUROHYPOPHYSIS: Posterior pituitary has 2 parts--

(pars nervosa & infundibulum/stalk)

Downgrowth of neural ectoderm of hypothalamus

NEUROHYPOPHYSIS:

stalk/stem carries axons from hypothalamus, contains portal veins & primary capillary plexus (median eminence)

Infundibulum

Pars nervosa - axon terminals

paraventricular nuclei make

oxytocin

supraoptic nuclei make

ADH

Hormones moved from hypothalamus via ______ with neurophysin

hypothalamo- hypophyseal tract

Unmyelinated axons in the infundibulum Stored for release in _____

pars nervosa

Posterior pituitary hormones:

ADH (Vasopressin) and Oxytocin

controls blood pressure by altering permeability of renal collecting tubules/ducts

ADH (Vasopressin)

↓ production of ADH => ↑ urine production (as in diabetes insipidus)

ADH (Vasopressin)

ADH (Vasopressin): Synthesized by neuron cell bodies in ______ of hypothalamus

supraoptic nucleus

ADH: Synthesized by neuron cell bodies in supraoptic nucleus of ______

hypothalamus

—promotes smooth Mm contraction in uterus & breast (especially during labor & lactation)

Oxytocin

Oxytocin: Synthesized by neuron cell bodies in paraventricular nucleus of ____

hypothalamus

Oxytocin: Synthesized by neuron cell bodies in ______ of hypothalamus

paraventricular nucleus

Axons end in the pars nervosa *Endings form large, fusiform swellings called ____ filled with secretory product

Herring bodies

T/F: Herring bodies filled with ____ product

secretory

Pars nervosa: Surrounded by specialized glial-like cells called _____

pituicytes

_____ is also known as the epiphysis cerebri or the pineal body.

The pineal gland is also known as the _____ or the pineal body.

epiphysis cerebri

The pineal gland is also known as the epiphysis cerebri or the ____

pineal body.

Pineal gland is found in the posterior extremity of the third ventricle and is attached by the pineal stalk to the _____

diencephalon.

Pineal Gland: Communicates with hypothalamus; acts as ____ in lower vertebrates

photoreceptor

Pineal Gland: Translates light intensity & _____ into endocrine activity—important in circadian rhythms & seasonal reproductive cycles

duration (photoperiod)

important in circadian rhythms & seasonal reproductive cycles

pineal gland

Secretes hormone melatonin => change in color intensity with reproductive cycle & serotonin (vasoconstrictor; neurotransmitter)

Pineal Gland:

stimulates melanophores, chromatophores (pigment-containing cells) => change in color intensity with reproductive cycle & serotonin

melatonin

Pineal Gland: Secretes hormone melatonin (stimulates melanophores, chromatophores (pigment-containing cells) => change in color intensity with reproductive cycle & ___

serotonin (vasoconstrictor; neurotransmitter)

(vasoconstrictor; neurotransmitter)

serotonin

In mammals,____ has anti-gonadal effect, ↓ sex activity

melatonin

Melatonin => ____ from hypothalamus => ↓ sex hormone secretion from gonads

↓ GNRH

are the most common cell types, comprising 95% of all cells. They are arranged in clumps and cords within the lobules. Histologic characteristics: Neuronal-like cells, they have large, irregular nuclei.

Pinealocytes

____ cells—support cells such as astrocytes, microglial cells

Neuroglial cells (= interstitial cells)

--(= “brain sand”, pineal sand) --Calcified accretions of Ca & Mg phosphate in aging individuals..radiopaque

corpora arenacea

Synthesis and secretion of melatonin is dramatically affected by ____

light exposure to the eyes.

The fundamental pattern observed (melantonin synthesis) is that serum concentrations of melatonin are ____ during the daylight hours, and ____ during the dark.

low: increase to a peak

The duration of melatonin secretion each day is directly proportional to the _______

length of the night.

SAD stands for:

Seasonal Affective Disorder