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Microanatomy > Unit 6 - Endocrine Glands > Flashcards

Unit 6 - Endocrine Glands Flashcards

1
Q

what are mechanisms of hormone actions?

A
  1. membrane-impermeable (hydrophilic)
    - receptors located on cell surface (don’t enter cell)
    - act via secondary messengers
    - ex: peptides, PRO, glycoPRO, modified AA
  2. membrane-permeable (hydophobic)
    - intracellular receptors are DNA-binding PRO that affect transcription
    - ex: steroid, TH
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2
Q

what are typical features of cells producing PRO hormones?

A
  • abundant RER
  • prominent Golgi
  • hormones often stored in secretory granules
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3
Q

what are typical features of cells producing steroid normones?

A
  • central nucleus
  • lipid droplets in cytoplasm
  • abundant SER for cholesterol synthesis
  • spherical mitochondria with characteristic tubular/vesicular cristae
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4
Q

structure of anterior pituitary

A

derived from oral ectoderm
-consists of epithelial tissue = adenohypophysis
3 regions are pars tuberalis, pars distalis, and pars intermedia

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5
Q

structure of posterior pituitary

A

derived from neural ectoderm
-consists of neurons and glia = neurohypophysis
2 regions arei nfundibular stalk and pars nervosa

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6
Q

how are cells in anterior pituitary divided?

A
  1. chromophils - basophils and acidophils

2. chromophobes - stem/progenitor cells, cells that released granules, or lost granules during fixing

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7
Q

what are acidophils in anterior pituitary?

A

produce 2 types of PRO hormones

  • somatotropic/GH
  • mammotropic hormone/prolactin
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8
Q

what are basophils in anterior pituitary?

A

glycoPRO hormones: FSH, LH, TSH

small polypeptides: ACTH, beta-LPH (lipotropin)

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9
Q

what are the percentages of secretory cells in anterior lobe? the hormone secreted? its role?

A

somatotrope: 50% - GH - growth of long bones
lactotrope: 15-20% - PRL - stimulate milk secretion
gonadotrope: 10% - FSH and LH - regulate ovarian follicle development, spermatogenesis, estrogen, and androgen secretion
thyrotrope: 5% - TSH - regulate TH secretion
corticotrope: 15-20% - ACTH - stimulate adrenal cortex hormone secretion
- also lipotropin - promotes utilization of fat

first 2 are acidophilic, last 3 are basophilic

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10
Q

in what parts of the anterior pituitary are hormones produced?

A

pars distalis and pars tuberalis
-the pars intermedia is largely inactive in adults, and has colloid-filled follicles and (Rathke’s) cysts of unknown function

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11
Q

what kinds of cells does the neurohypophysis have?

A

axons and glial cells (pituicytes)

  • has NO secretory cells
  • cell bodies of neurons are in hypothalamus
  • hormones are stored in dilated axons
  • -eosinophilic dilations are called Herring bodies
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12
Q

structure and origin of adrenal glands?

A

have outer layer (cortex) and inner layer (medulla)

  • cortex has epithelial origin and 3 concentric zones: zona glomerulosa outer - zona fasciculata - zona reticularis inner)
  • medulla has neuronal origin
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13
Q

what kinds of cells are in the adrenal cortex?

A

typical features of steroid-producing cells; usually have foamy appearance = foam cells

  • central nucleus
  • acidophilic cytoplasm with lipid droplets
  • abundant SER for cholesterol synthesis
  • spherical mitochondria with characteristic tubular cristae contain enzymes involved in synthesis of steroid hormones from cholesterol
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14
Q

what kinds of cells are in the adrenal medulla?

A

cells have electron-dense secretory granules that react with chromium and silver salts (so called chromaffin or argentaffin)
-make catecholamines (epinephrine and norepinephrine)

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15
Q

what hormones are made by the adrenal cortex, and where?

A

zona glomerulosa: mineralcorticoids (mostly aldosterone to regulate salt balance)
-regulated by angiotensin II
zona fasciculata: glucocorticoids (mostly cortisol), some DHEA (regulate glucose metabolism)
-regulated by ACTH
zona reticularis: cortisol and weak androgen DHEA (glucose regulation and testosterone production)
-regulated by ACTH

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16
Q

what hormones are made by the adrenal medulla, and where?

A

all of medulla makes catecholamines (E/NE) for fight-or-flight response
-regulated by SNS

17
Q

what happens to the adrenal cortex if the pituitary is removed, or there is a tumor?

A

no hypophysis: cortex gets smaller, medulla stays the same

tumor: cortex gets larger, medulla stays the same

18
Q

Cushing’s syndrome

  • effects
  • ccauses
A

adrenal cortex hyperactivity

  • excessive cortisol causes weight gain, central obesity, hyperglycemia, easy bruising
  • ACTH-independent: 20%
  • -adrenal adenoma: 10%
  • -adrenal carcinoma: 5%
  • -other causes: 5%
  • ACTH-dependent: 80%
  • -pituitary adenoma: 70%
  • -ectopic ACTH secretion by a tumor: 10%
19
Q

islets of Langerhans

A

compact masses of endocrine tissues embedded w/in exocrine tissue of pancreas

  • polygonal/round cells arranged in cords
  • typically PRO-secreting cells (abundant RER, golgi)
  • lightly stained (lighter than exocrine tissue)
  • cells have secretory granules
  • make polypeptide hormones
20
Q

what is the quantity of cell types in islets of Langerhans?

A

alpha: 20% - in periphery - make glucagon
beta: 70% - centrally located - make insulin
delta: 5-10% - make somatostatin to inhibit other islet hormones, inhibit GH, TSH, and HCl secretion
F or PP: very rare - make pancreatic polypeptide to stimulate gastric chief cells but inhibit bile and pancreatic enzyme secretion

21
Q

where is the thyroid and structure?

A

anterior to trachea

  • has follicles, spherical structures lined by simple epithelium and filled with colloid
  • colloid has storage form of TH called thyroglobulin
22
Q

what do thyroid follicular cells look like and do?

A

vary in shape from cuboidal to low columnar

  • have features characteristic of PRO-secreting cells (abundant RER and golgi)
  • activity regulated by TSH made in anterior pituitary
  • T3/4 regulate basal metabolic rate, body growth/development, and heat production
23
Q

what do parafollicular cells (C-cells) look like and do?

A

larger in size than follicular cells

  • appear pale in H&E prep
  • located in basal lamina of follicles or between follicles
  • make calcitonin that inhibits bone resorption and promotes calcification of bone (opposite of PTH)
  • regulated by blood Ca++ levels
24
Q

there are parathyroid glands? what kind of cells do they have?

A

4 small oval glands on the back of the thyroid

  • chief cells - make PTH
  • oxyphil cells - no known function
25
Q

what do parathyroid gland chief cells do?

A

abundant small polygonal cells that are pale staining, and slightly acidophilic cytoplasm

  • make PTH (polypeptide) that increase blood Ca++ level by regulating osteoclast activity, kidney excretion of Ca++, vit D synthesis, and intestinal absorption of Ca++
  • regulated by Ca++ level in blood
26
Q

what do oxyphil cells of parathyroid gland do?

A

large cells that are highly acidophilic (thus oxyphilic)

  • less abundant than chief cells
  • unknown function, but may make some PTH
27
Q

what are some hormones secreted by non-endocrine hormones?

A

heart - ANP
kidney - erythropoietin, reinin
stomach/SI - enteric hormones
adipose tissue - leptin, adiponectin, steroid hormones

28
Q

what does ANP do?

A

in heart; regulates BP and electrolyte balance

29
Q

what do adipose hormones do?

  • leptin
  • adiponectin
A

leptin: regulate appetite and metabolism
adiponectin: regulate FA and glucose metabolism, and modulates sensitivity to insulin

30
Q

what does B-FLAT refer to?

A

basophilic cells of anterior pituitary secrete FSH, LH, ACTH, and TSH

31
Q

what does GPA refer to?

A

GH and PRL are secreted by acidophilic cells of anterior pituitary

32
Q

what does “salt, sugar, sex” refer to?

A

order or products of adrenal cortex:

  • mineralcorticoids (aldosterone)
  • glucocorticoids (cortisol)
  • androgens

Microanatomy (14 decks)

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