Endocrine System Histo Flashcards by Jamie Jones

secrete onto a surface, either directly or through a duct

exocrine gland

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secrete internally; ductless glands; secrete hormones; primarily utilize cardiovascular system for distribution

endocrine gland

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2 types of hormones

circulating and local hormones

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local hormones are ___ or ____

paracrines; autocrines

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main visceral control center for body; the autonomic control center; regulates body temperature, food intake, water balance/thirst, sleep-wake cycles, sexual behavior and endocrine system functioning; its influence on the body is vital for maintaining homeostasis

hypothalamus

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hypothalamus is major link betw ____ and ____ systems; considered the command center for the endocrine system; its secretions can regulate other glands

endocrine; nervous

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hypothalamus produces 9 hormones: 5 ____ hormones which impact/control the anterior pituitary; 2 ____ hormones which impact/control the ant. pituitary, and 2 other hormones released from the ____

releasing; inhibiting; posterior pituitary

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the hypothalamus is connected to the pituitary gland by the ____; the pituitary gland is known as the ____

infundibulum; master gland of the endocrine system

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together the hypothalamus and the pituitary gland regulate virtually all aspects of ____, ____, ____, and _____

growth; development; metabolism; homeostasis

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pituitary gland also known as ____; it sits in the ____ within the ____ of the sphenoid bone

hypophysis; hypophyseal fossa; sella turcica

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bulk of the anterior lobe of the pit. gland; cords of epithelial cells interspersed with fenestrated capillaries; develops from anterior wall of Rathke’s pouch

pars distalis

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thin remnant of posterior wall of Rathke’s pouch; next to pars distalis; surrounds a series of colloid-filled follicles that represent the residual lumen of Rathke’s pouch

pars intermedia

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from thickened lateral walls of Rathke’s pouch; forms a collar or sheath around the infundibulum; most cells here are basophilic gonadotropic cells

pars tuberalis

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anterior pituitary/anterior lobe/adenohypophysis has 3 parts:

pars distalis
pars intermedia
pars tuberalis

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neurosecretory axons and their endings

pars nervosa

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contains neurosecretory axons forming the hypothalamo-hypophyseal tracts

infundibulum

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2 parts of the posterior lobe/posterior pituitary/neurohypophysis

pars nervosa

- infundibulum

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the hypophysis or pituitary gland is derived in part from an outpocketing of the ____ lining the roof of the mouth called the _____ and in part from an outpocketing of the _____ lining the floor of the hypothalamus called the _____

ectoderm; hypophyseal (Rathke’s pouch)

neuroectoderm; neurohypophyseal bud

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the ____ of the pituitary gland develops from the roof of the mouth

anterior lobe

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release of hormones from the anterior pituitary is stimulated by _____ (5) and suppressed by ____ (2) from the ____ as well as through _____

releasing hormones; inhibiting hormones; hypothalamus; negative feedback

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the regulating hormones from the hypothalamus reach the anterior lobe of the pituitary gland by the _____

hypothalamo-hypophyseal portal system

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cluster of specialized cells called ____ in the hypothalamus synthesize the hypothalamic releasing and inhibitory hormones in their cell body

neurosecretory neurons

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these hypothalamic hormones travel down the axons of the neurosecretory cells to the axon terminals where they exit via ____

exocytosis

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these hormones diffuse into the hypophyseal portal system at the ____

primary plexus of the hypophyseal portal system (fenestrated capillaries)

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these hormones then pass from the primary plexus of the hypophyseal portal system to the ____ into the _____, bringing these hypothalamic hormones directly to the cells of the ____

hypophyseal portal veins; secondary plexus of the hypophyseal portal system; pars distalis

there are two groups of secretory cells in pars distalis based on staining affinity:

chromophils and chromophobes

chromophils are 50% of pars distalis; hormone stored in ____

cytoplasmic granules

chromophils are either ___ or ____

basophils (affinity for basic dyes, 10% of pars distalis) | acidophils (affinity for acidic dyes, 40% of pars distalis)

three types of basophils from most to least abundant

1. corticotropes (ACTH cells)- 15-20% of anterior lobe 2. gonadotropes (FSH and LH cells)- 10% of anterior lobe 3. thyrotropes (TSH cells)- 5% of anterior lobe

two types of acidophils from most to least abundant

1. somatotropes (GH cells)- 50% of anterior lobe | 2. lactotropes (mammotropes, PRL cells)- 15-20% of anterior lobe

50% of pars distalis; with few or no secretory granules; stain weakly; clear cells; reserve/primitive cells; undifferentiated cells; can become chromophils

chromophobes

7 hormones of the anterior pituitary

1. Human growth hormone (hGH) 2. thyroid stimulating hormone (TSH) 3. follicle-stim hormone (FSH) 4. luteinizing hormone (LH) 5. prolactin (PRL) 6. adrenocorticotrophic hormone (ACTH) 7. melanocyte-stim hormone (MSH)

human growth hormone (hGH) secreted by _____

somatotropes (acidophils)

thyroid-stimulating hormone (TSH) secreted by ____

thyrotropes (basophils)

follicle-stim hormone (FSH) secreted by ____

gonadotropes (basophils)

luteinizing hormone (LH) secreted by _____

gonadotropes (basophils)

Prolactin (PRL) secreted by _____

lactotropes (acidophils)

adrenocorticotrophic hormone (ACTH) secreted by ____

corticotropes (basophils)

melanocyte-stim hormone (MSH) secreted by ____

corticotropes (basophils)

human growth hormone also called ____

somatotropin

the posterior pituitary (posterior lobe/neurohypophysis) does not ____ hormones (i.e. no secretory cells here), but instead ____ and _____ two hormones

synthesize; stores; releases

posterior pituitary (pars nervosa) contains the ___ and ___ of hypothalamic neurosecretory neurons, along with ____, ____ and ____

axons; axon terminals | along with fibroblasts, mast cells, and pituicytes

a type of glial cells, resembling the astrocyte, that associates fenestrated capillaries; cell has many branches; pigment vesicles in cytoplasm; nuclei round or oval; most common cell type in the posterior pituitary

pituicytes

the two hormones released from the posterior pituitary are:

1. oxytocin (OT) | 2. antidiuretic hormone (ADH or vasopressin)

these two hormones are synthesized within the cell bodies of the _____ in the ____

neurosecretory neurons; hypothalamus

the axons of the neurosecretory neurons form the _____ in the _____

hypothalamo-hypophyseal tract; infundibulum

the hormones, once formed in the hypothalamus, are transported down the axons in the hypothalamo-hypophyseal tract to the posterior pituitary where they are stored in ____ in dilated portions of the axons near the terminals called _____

secretory vesicles; Herring bodies (aka neurosecretory bodies)

neuroendocrine gland that regulates daily body rhythm; day/night cycle (circadian rhythm)

pineal gland/body

major hormone production of the pineal gland

melatonin

two cell types of the pineal gland

1. pinealocytes (parenchymal cells) 95% of cells | 2. interstitial (glial) cells - 5% of cells

characteristic presence of ____ in the pineal gland

corpora arenacea (brain sand)

adrenal glands or suprarenal glands have a ___ around the gland

capsule

the cortex of the adrenal gland is a large, peripheral area just below the capsule that makes up 80-90% of the gland; contains ____ cells

steroid-secreting

the medulla of the adrenal gland is a smaller, centrally located area that contains _____ cells

catecholamine-secreting

3 regions of the adrenal cortex

1. zona glomerulosa 2. zona fasciculata 3. zona reticularis

the thickest of the 3 adrenal cortex regions; contains cells that are arranged in long rows/cords

zona fasciculata

zona glomerulosa (outermost layer) secretes _____, mainly _____

mineralocorticoid hormones; aldosterone

zona fasciculata (middle layer) secretes _____, mainly ____

glucocorticoid hormones; cortisol

zona reticularis (deepest layer) secretes _____, mainly ____

androgen hormones; DHEA

adrenal medulla chromaffin cells secrete 3 catecholamine hormones:

epinephrine, norepinephrine, and a small amount of dopamine

Regulates Na+, K+, and water; Control of blood pressure

mineralocorticoid hormones such as aldosterone

Regulate glucose and fatty acid metabolism; Suppresses the immune system; Provides resistance to stress

glucocorticoid hormones like cortisol

Assists in early growth of axillary and pubic hair in both sexes

androgen hormones like DHEA

Intensify sympathetic responses in other parts of the body

catecholamines like epinephrine (adrenaline) and norepinephrine (noradrenaline)

a modified sympathetic ganglion of the autonomic NS (ANS)

adrenal medulla

the adrenal medulla develops from the same embryonic tissues as all other ____ in the body (i.e. neural crest cells), but the cells found in the medulla lack ____ and do not release ____

sympathetic ganglia; axons; neurotransmitter

instead, these modified neurons (called _____) cluster around ____ and release hormones

chromaffin cells; blood vessels

the chromaffin cells are controlled by ____, which allows for quick signalling to the chromaffin cells to release hormones via _____

sympathetic preganglionic neurons; exocytosis

the ____ component of the pancreas synthesizes and secretes hormones

endocrine

the endocrine portion seen in the pancreas as _____, found throughout the pancreas but most numerous in the tail

islets of Langerhans (aka pancreatic islets, 100-200 micrometers in diameter)

endocrine portion of pancreas stains ___ compared to the exocrine portion (i.e. pancreatic acini)

pale

3 principle cells of the islets of langerhans

1. beta or B cells 2. alpha or A cells 3. delta or D cells

beta cells are 70% of the islets; they synthesize and secrete ____; cells found toward ___ of islet

insulin; center

alpha or A cells are 17% of the islets; they synthesize and secrete ____; cells found toward ____ of islet

glucagon; periphery

delta or D cells are 7% of islets; they synthesize and secrete ____ (which is identical to _____); cells are found toward ____ of islet

somatostatin; growth hormone inhibiting hormone (GHIH) from the hypothalamus periphery

lowers blood glucose level as it signals for an acceleration of glucose transport into cells and the conversion of the glucose into glycogen (glycogenesis).

insulin

raises blood glucose level as it signals for the acceleration of the breakdown of glycogen into glucose in the liver (glycogenolysis); this glucose is released into the blood.

glucagon

inhibits insulin and glucagon secretion

somatostatin

the thyroid gland has a ___ and ____, creating lobules

fibrous capsule; septa

the thyroid gland contains ____

thyroid follicles

the walls of the thyroid follicles are made up by follicular cells (____ to ____) that are responsible for the production of _____

simple squamous; low columnar; thyroid hormones

the thyroid hormones are ____ and ____

1. thyroxine (aka tetra-iodothyronine or T4)- 4 atoms of iodine 2. tri-iodothyronine (T3)- 3 atoms of iodine

T3 and T4 are important for ____, ____, and control of ____ and ____ of body cells

growth; cell differentiation; basal metabolic rate; oxygen consumption

the follicles contain ____ which is a gel-like mass; the main component of this substance is _____, a large iodinated glycoprotein which is an inactive form of the thyroid hormones

colloid; main comp of colloid is thyroglobulin

when thyroid hormones need to be released, thyroglobulin is brought back into the ____, modified, and then released as the thyroid hormones into ____ that surround the follicles

follicular cells; fenestrated blood capillaries

_____ or ____ are also found in the thyroid gland; they are larger than follicular cells and stain less intensely

parafollicular cells; C cells

parafollicular cells are responsible for the production of _____

calcitonin (CT)

parafollicular cells may be part of the ____ or found between the follicles

follicular epithelium

calcitonin decreases the level of ____ in the blood by encouraging ____ to be deposited in bone matrix (i.e. building of bone) and responsible for inhibiting the action of ____ (cells that normally resorb or breakdown bone’s extracellular matrix).

calcium; calcium salts; osteoclasts

_____ system controls the secretion of calcitonin ; ____ stimulate the secretion of CT, and ____ inhibit the secretion of CT

negative feedback; high blood Ca levels; low blood Ca levels

the parathyroid glands have a surrounding ____ with ___ that enter gland

capsule; septa

two types of cells located in the parathyroid glands

1. chief cells | 2. oxyphil cells

chief cells produce ____; they are the most numerous of cells; small cell, round centrally located nucleus ; ____ staining and slightly ____ cytoplasm

parathyroid hormone (RTH); pale; acidophilic

larger cell with very acidophilic cytoplasm; more common in older individuals; unknown function

oxyphil cells

PTH ____ the level of Ca in the blood by stimulating ____ to resorb bone which releases Ca into the blood; PTH additionally acts on the ____ to slow the rate of Ca loss from the blood to the urine

increases; osteoclast; kidneys

____ system controls the secretion of PTH; ____ stimulate secretion of PTH and ____inhibit PTH secretion

negative feedback; low blood Ca levels; high blood Ca levels

Endocrine System Histo Flashcards

(96 cards)