[HISTO] HORMONE SECRETING CELLS & PITUITARY 1 Flashcards

1
Q

Endocrine glands are formed of

A

secretory cells
CT stroma
fenestrated capillaries

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2
Q

steroid hormone secreting cells are characterized by

A

sER
mitochondria with tubular cristae
lipid droplets

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3
Q

steroid hormones produce

A

precursor hormones which form steroids by cholesterol metabolism in mitochondria/sER

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4
Q

hormones which can easily diffuse through cell membrane

A

steroid hormones (lipophilic)

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5
Q

hormones which require cell surface receptor & 2nd messenger to mediate their effect

A

peptide hormones (hydrophilic)

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6
Q

peptide hormone secreting cells are characterized by

A

rER
Golgi complex
secretory granules

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7
Q

how do peptide hormones achieve their effect

A

by binding to membrane receptors—>hormone-receptor complex—> (+) 2nd messenger—>2nd messenger mediates effect

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8
Q

amino acid hormones examples

A

thyroid hormones
catecholamines
dopamine
ALL DERIVED FROM TYROSINE

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9
Q

pure endocrine glands (5)

A

1-pituitary
2-pineal
3-thyroid
4- parathyroids
5-adrenal

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10
Q

mixed endocrine glands (6)

A

1-islets of Langerhans
2-interstitial cells of Leydig
3- Hepatocytes
4-ovarian follicles
5-corpus luteum
6-Hypothalamic neurosecretory cells

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11
Q

scattered isolated cells (5)

A

1-enteroendocrine cells
2-juxtaglomerular cells
3- cardiac muscle fibers
4- white adipocytes
5- epithelial reticular cells (thymus)

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12
Q

function of enteroendocrine cells

A

secrete ghrelin in stomach mucosa
(+) appetite & GH release

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13
Q

function of juxtaglomerular cells

A

*secrete renin
control GFR & BP

*secrete erythropoietin
(+) erythrocyte production in red marrow
(-) erythrocyte precursors apoptosis

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14
Q

function of cardiac muscle fibers

A

secrete ANF
promotes Na-H2O loss in urine
(DIURETIC EFFECT)

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15
Q

renin’s effect

A

(+)aldosterone production
↑ Na-H2O retention
∴ ↑ BP

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16
Q

renin release increases in case of

A

low BP

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17
Q

function of white adipocytes

A

secrete leptin (satiety factor)
regulates appetite + adipocytes formation

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18
Q

function of epithelial cells of thymus

A

differentiation & maturation of T-thymocytes

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19
Q

modes of hormone secretion

A

paracrine
juxtacrine
autocrine

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20
Q

juxtacrine secretion

A

signaling molecules remain on cell’s surface & mediates respone when target cells make contact

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21
Q

paracrine secretion?
examples?

A

act on target cells a short distance away
ex: gastrin, histamine

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22
Q

autocrine secretion?
examples?

A

acts on itself
ex: prostaglandins

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23
Q

gastric hormone is secreted by?
mode of secretion?

A

pyloric G cells
paracrine

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24
Q

principle organizers of endocrine glands

A

hypothalamus & pituitary

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25
Q

pituitary is regulated by

A

(+): hypothalamic secretions
(-): negative feedback

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26
Q

pituitary gland lies outside the___

A

blood-brain barrier

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27
Q

hypothalamus is regulated by

A

negative feedback from pituitary & target organ hormones

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28
Q

pituitary grows in size during

A

pregnancy

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29
Q

site of pituitary

A

sella turcica

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30
Q

pituitary is physically connected to hypothalamus by

A

infundibular stalk

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31
Q

roof of pituitary is formed by

A

diaphragma sellae (dura)

32
Q

embryological divisions of pituitary

A

adenohypophysis
neurohypophysis

33
Q

anatomical divisions of pituitary

A

anterior lobe= Pars distalis & tuberalis

posterior lobe= Pars nervosa & intermedia + neural stalk

34
Q

adenohypophysis is formed of

A

Pars distalis
Pars intermedia
Pars tuberalis

35
Q

oral component of pituitary

A

adenohypophysis

36
Q

neural component of pituitary

A

neurohypophysis

37
Q

adenohypophysis develops from

A

ectodermal up-growth from buccal cavity that forms Rathke’s pouch

38
Q

neurohypophysis develops from

A

down growth from hypothalamus

39
Q

neurohypophysis is formed of

A

Pars nervosa
Infundibular stalk

40
Q

main part of gland which represents 75% of total gland volume

A

Pars distalis

41
Q

parts of pars distalis

A

stroma= capsule & reticular CT
parenchyma= secretory cells & fenestrated capillaries

42
Q

types of cells of pars distalis

A

chromophobes
chromophils

43
Q

chromophobes characteristics

A

smaller
polygonal
pale cytoplasm
central rounded nucleus
few granules (EM)

44
Q

types of chromophobes

A

1-partly degranulated cells (resting stage)
2-undifferentiated stem cells
3-follicular stellate (phagocytic/supporting. NOT secretory)

45
Q

types of chromophils

A

acidophils
basophils

46
Q

types of acidophils

A

somatotrophs
mammotrophs

47
Q

types of basophils

A

thyrotrophs
gonadotrophs
corticotrophs

48
Q

acidophils characteristics

A

35% of total pars distalis cells
site: posterolateral
smaller than basophils
rounded/polygonal
vesicular nuclei
!!PAS NEGATIVE!!
*rER
*Golgi
*secretory granules
GRANULES STAIN BY EOSIN & ORANGE G

49
Q

Basophils characteristics

A

15% of total pars distalis cells
site: peripherally
larger
angular
vesicular nucleus
!!PAS POSITIVE!!
*rER
*Golgi
GRANULES STAIN BY Hx

50
Q

why are the granules of basophils PAS positive?

A

their hormones are glycoproteins in nature

51
Q

function of basophils

A

secrete trophic hormones

52
Q

most abundant cells in pars distalis

A

somatotrophs

53
Q

somatotrophs characteristics

A

close to capillaries
ovoid
electron dense granules
*rER
*Golgi
STAINED ORANGE BY ORANGE G
PAS NEGATIVE

54
Q

somatrophs functions

A

secrete GH

55
Q

GH secretions induces

A

somatomedins synthesis by liver cells—>protein synthesis–>growth & elongation of long bones

56
Q

GH secretion is controlled by

A

(+): GhRH & Ghrelin
(-): GIH (Somatostatin)

57
Q

mammotrophs characteristics

A

polygonal
*few rER
*Golgi
enlarge during pregnancy thru hypertrophy & hyperplasia
PAS NEGATIVE

58
Q

mammotrophs function

A

secrete PRL
(+)mammogenesis
initiate + maintains milk secretion

59
Q

PRL secretion is controlled by

A

(+): PRH
(-): PIH (Dopamine)

60
Q

hyperplasia of pituitary in newborn is due to

A

high estrogen levels from the mother

61
Q

thyrotrophs characteristics

A

LEAST in no.
SMALLEST granules
Large
polygonal
PAS positive

62
Q

function of thytrotrophs

A

secrete TSH

63
Q

TSH secretion is controlled by

A

(+): TRH
(-): negative feedback by T3 & T4

64
Q

gonadotrophs characteristics

A

fusiform
PAS POSITIVE
electron dense granules

65
Q

gonadotrophs function

A

secrete FSH
* (+) maturation of ovarian follicle
* (+) spermatogenesis
*(+) androgen binding protein synthesis

secrete LH
*(+) ovulation
*(+) interstitial cells of Leydig–> (+) testosterone secretion

66
Q

LH in males is called

A

ICSH
(interstitial cell-stimulating hormone)

67
Q

androgen binding protein is synthesized by

A

Sertoli cells

68
Q

corticotrophs characteristics

A

oval
PAS POSITIVE
electron dense granules

69
Q

corticotrophs function

A

secrete POMC
*cleaved to ACTH
*cleaved to β-lipotropic hormone

70
Q

ACTH function

A

(+) zona fasiculata in adrenal cortex

71
Q

β-lipotropic hormone function

A

regulate lipid metabolism

72
Q

corticotrophic hormones secretion is controlled by

A

(+): CRH
(-): negative feedback by cortisol

73
Q

tropic hormones are released into capillaries of pars distalis by

A

tuberoinfundibular stalk

74
Q

axons of tuberohypophyseal neurons form?
terminates in?

A

tuberoinfundibular stalk
median eminence

75
Q

only hormones which are regulated by BOTH releasing & inhibiting tropic factors

A

GH
PRL