Endocrine Histo Flashcards Preview

Histology Sem 3 > Endocrine Histo > Flashcards

Flashcards in Endocrine Histo Deck (118)
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1
Q

Regulates the activities of different cells, tissues, and orgrans

A

Hormones

2
Q

Provides communication between different systems in the body and coordinates body growth and development, is similar to the nervous system

A

Endorcine system

3
Q

Provides endocrine and neuroendocrine control of the other endocrine glands

A

Pituitary gland and hypothalamus

4
Q

Pea-sized unpaired endocrine gland located at the base of the brain

A

Pituitary gland

5
Q

Where does the pituitary gland sit?

A

Sella Turcica

6
Q

Connects the pituitary gland to the hypothalamus

A

Infundibular stalk

7
Q

Surrounds the pituitary gland and is formed of dense irregular connective tissue

A

Capsule

8
Q

2 fundamental components of the pituitary gland

A

Adenohypophysis and Neuropophysis

9
Q

How does the adenohypophysis develop?

A

Develops as an invagintation of the ectoderm of the oral cavity known as Rathke’s pouch

10
Q

How are the adenohypophysis cells organized?

A

Clumps and cords around fenestrated capillaries

11
Q

Regions of the adenohypophysis

A

Pars distalis, pars intermedia, pars tuberalis

12
Q

Bulk of the anterior lobe of the adenohypophysis

A

Pars distalis

13
Q

Thin remnant of the wall of Rathke’s pouch

A

Pars intermedia

14
Q

Remnants of the Rathke’s pouch

A

Rathke’s cysts

15
Q

Lines the pars intermedia

A

Cuboidal epithelium

16
Q

Forms a collar or sheath around the infundibular stalk

A

Pars tuberalis

17
Q

5 cells of adenohypophysis

A

Corticotropes, somatotropes, lactotropes, gonadotropes, thyrotropes

18
Q

Basophils

A

Corticotropes, gonadotropes, thyrotropes

19
Q

Acidophils

A

Somatotropes, Lactotropes

20
Q

What do somatotropes secrete?

A

Somatotropin, aka growth hormone

21
Q

2 hormones that control the release of GH

A

GH releasing hormone (release) and somatostatin (inhibits)

22
Q

Most abundant endocrine cells in the adenohypophysis

A

Somatotropes

23
Q

What do lactoropes secrete?

A

Prolactin

24
Q

Hormone that controls the production and release of prolaction

A

Inhibited by dopamine, thyrotropin releasing hormone stimulates

25
Q

What do corticotropes produce?

A

Adrenocorticotropic hormone (ACTH)

26
Q

What does ACTH act on?

A

The cells of the adrenal cortex

27
Q

Controls the release of ACTH

A

Corticotropin-releasing hormone (CRH) released from the hypothalamus

28
Q

2 main hormones secreted by gonadotropes

A

Follicle-stimulating hormone (FSH) and lutenizing hormone (LH)

29
Q

Controls the secretion of the gonadotropes

A

Gonadotropin-releasing hormone released from the hypothalamus

30
Q

What do thyrotropes produce?

A

Thyrotropic hormone (TSH)

31
Q

Controls the release of TSH

A

TRH

32
Q

Part of the pituitary derived from nerve tissue

A

Neurohypophysis

33
Q

Regions of the neurohypophysis

A

Pars nervosa, infundibulum

34
Q

Glial cells in the neurohypophysis

A

Pituicytes

35
Q

What is secreted into the pars nervosa by the hypothalamus?

A

Oxytocin and anitduiretic hormone

36
Q

Large distended axon terminals of these neurons can sometimes be visualized as what?

A

Herring bodies

37
Q

What does the superior hypophyseal artery supply?

A

Pars tuberalis, infundibulum, median eminence, pars distalis

38
Q

Most prominent feature of the hypophyseal blood supply

A

Hypophyseal portal system

39
Q

What does the superior hypophyseal artery form upon arrival to the pituitary?

A

Primary capillary plexus

40
Q

Where does blood go after the primary capillary plexus?

A

Into the hypophyseal portal veins, into the secondary capillary plexus in the pars distalis

41
Q

Within which plexus do the hormones for the bloodstream exit the pituitary?

A

Secondary capillary plexus

42
Q

Blood supply to the pars nervosa

A

Inferior hypophyseal artery

43
Q

Unpaired pine-cone-shaped midline organ of the brain

A

Pineal gland

44
Q

Where is the pineal gland located?

A

Posterior end of the third ventricle of the brain, covered by cerebral hemispheres

45
Q

What does the pineal gland develop out of?

A

Outgrowth from the dicephalon

46
Q

What covers the pineal gland?

A

Pia mater forms the capsule, septa extends into the gland fron this capsule

47
Q

What are aggregates of calcuim phosphates found with the pineal gland?

A

Corpora arenacea, aka brain sand

48
Q

Principle cells of the pineal gland

A

Pinealocytes

49
Q

What do the spaces between the clusters of the pineal gland contain?

A

Axons, pinealocyte cell processes, blood vessels, corpora arenacea

50
Q

Describe pinealocytes on microscope

A

Large euchromatic nuclei with a prominent nucleolus

51
Q

What do pinealocytes secrete?

A

Melatonin

52
Q

How does the information about the light/dark cycles reach the pineal gland?

A

Retinothalamic tract, connecting the suprachiasmic nucleus with the sympathetic neural tracts

53
Q

How is the synthesis/secretion of melatonin controlled?

A

Norepinephrine released by the sympathetic neurons

54
Q

What is the activity of melatonin?

A

Inhibits the steroidogenic activity of the gonads

55
Q

Supporting cells of the pineal gland

A

Glial cells (interstitial cells)

56
Q

Describe the glial cells of the pineal gland

A

Nuclei are smaller and more heterochromatic

57
Q

Divisions of the adrenal gland

A

Cortex(yellow peripheral layer) and medulla(central reddish-brown layer)

58
Q

Embryological origin of the cortex

A

Mesenchyme, mesodermal in origin

59
Q

Embryological origin of the medulla

A

Neural crest cells, ectodermal in origin

60
Q

Tissue of the capsule

A

Dense connective tissue with thin trabeculae into the parenchyma of the gland

61
Q

Forms the majority of the adrenal gland

A

Cortex (90% of the gland)

62
Q

Steriod-producing part of the gland

A

Cortex

63
Q

What does the cortex produce?

A

Mineralocorticoids, glucocorticoids, some androgens

64
Q

Characteristics of steriod-producing cells

A

Numerous lipid droplets, mitochondria with tubular cristae, abundant smooth ER

65
Q

What do cortex cells do with steriod hormones?

A

Released immediately

66
Q

Divisions of the adrenal cortex

A

Zona: glomerulosa, fasciculata, reticularis

67
Q

Cell appearance of the zona glomerulosa

A

Closely packed cubodial/pyramidal cells, arranged into arched cords/curved columns, surrounded by numerous fenestrated sinusoidal capillaries

68
Q

What do the cells of the zona glomerulosa secrete?

A

Mineralocorticoids

69
Q

Purpose of mineralocorticoids

A

Regulate sodium and potassium honeostasis and water balance

70
Q

Principle mineralocorticoid of the zona glomerulosa

A

Aldosterone (causes reabsorption of sodium)

71
Q

Stimulates the zona glomerulosa to produce aldosterone

A

Angiotension II

72
Q

Makes up the majority of the adrenal gland

A

Zona fasciculata

73
Q

Describe the zona fasciculata

A

Cells form one or two cell-thick straight cords that run at a right angle to the capsule and have fenestrated sinusoidal capillaries between them

74
Q

Large secretory cells in the zona fasciculata

A

Spongiocytes

75
Q

Secretion of the spongiocytes

A

Mostly glucocorticoids

76
Q

Role of glucocorticoids

A

Increase metabolism of glocus and fatty acids, depress the immune and inflammatory responses

77
Q

How do glucocorticoids depress the immune and inflammatory responses?

A

Suppress the production of interleukin-1 and IL-2 by lymphocytes and macrophages, also supress lymphoblast mitosis within lymph nodes

78
Q

What controls glucocorticoid production?

A

ACTH produced by the corticotropes of the anterior pituitary lobe. Necessary for cell growth and increased blow flow thru the adrenal gland

79
Q

Innermost layer of the cortex

A

Zona reticularis

80
Q

Appearance of the zona reticularis

A

Relatively small cells arranged into irregular cords that anastomose to form a network, contain fewer lipid droplets and stain more intensely with eosin

81
Q

Contants of zona reticularis cells

A

Lipofuscin granules

82
Q

What do the cells of the zona reticularis secrete?

A

Androgens and glucocorticoids

83
Q

Composition of the adrenal medulla

A

Polyhedral cells arranged into clumps or cords supported by reticular fibers, with an extensive network of fenestrated capillaries

84
Q

Principle secreting cells of the adrenal medulla

A

Chromaffin cells

85
Q

Where are chromaffin cells derived from?

A

Neural crest cells, so they are modified postsynaptic neurons that lack axons

86
Q

What is unique about the granules of the chromaffin cells?

A

Accumulate and store hormones

87
Q

How to differentiate between norepinephrine and epinephrine cells in chromaffin cells?

A

Epi cells are smaller and more abundant. NE cells have larger secretory granules

88
Q

Innervation of chromaffin cells

A

Synaptic nerve fibers

89
Q

Causes the degranulation of chromaffin cells

A

Release of acetylcholine from the synaptic terminals

90
Q

How are the hormones of the chromaffin cells delivered to the body?

A

Via the bloodstream thru fenestrated capillaries

91
Q

Modulate the activity of chromaffin cells and innervate blood vessels within the medulla

A

Ganglion cells

92
Q

Irrigates the adrenal gland capsule

A

Capsular arteries

93
Q

Blood supply within the cortex

A

Cortical arteries that branch and form a dense network of fenestrated cortical sinusoidal capillaries

94
Q

Blood supply within the adrenal medulla

A

Medullary arteries that form a dense network of fenestrated medullary sinusoidal capillaries AND the cortical capillaires

95
Q

Recieves blood from smaller blood vessels withing the medulla

A

Adrenimedullary collecting veins

96
Q

Drains the blood from the adrenal gland

A

Central adrenomedullary vein (IVC on right side, left renal vein on left side)

97
Q

Main structural unit of the thyroid gland

A

Thyroid follicle

98
Q

Structure of a thyroid follicle

A

Spherical structure forms by a layer of simple cuboidal follicular epithelium surrounding a cyst-like central cavity

99
Q

Contents of thyroid follicle

A

Colloid

100
Q

2 types of cells of the follicular epithelium

A

Follicular and parafollicular cells

101
Q

Principle endocrine cells of thyroid gland

A

Follicular cells

102
Q

Origin of thyroid follicular cells

A

Endodermal

103
Q

2 main hormones synthesized by follicular cells

A

Thyroxine (T4) and Triiodothyronine (T3)

104
Q

Synthesized in RER of follicular cells and is secreted into the lumen of the follicle

A

Thyroglobulin

105
Q

How is iodide used in follicular cells?

A

Actively transported from blood into cytoplasm, iodine is oxidized to iodine and released into the colloid

106
Q

How are T4 and T3 stored in the follicular cells?

A

Linked to thyroglobulin molecule to remain stored in cell

107
Q

How are T4 and T3 released?

A

TSH causes cells to take up thyroglobulin resobring the colloid, thyroglobulin is borken down by lysosomes, releasing T3:T4 (1:20) and diffuse into the blood

108
Q

Main function of parafollicular cells

A

Synthesis of calcitonin

109
Q

What does calcitonin do?

A

Lowers blood calcium levels by suppressing the resorptive activity of osteoclasts and promoting calcium deposition in bones by osteoblasts

110
Q

Where are parafollicular cells derived from?

A

Neural crest

111
Q

Small endocrine glands usually embedded with the thyroid

A

Parathyroid glands

112
Q

Arrangement of parathyroid gland cells

A

Arranged into cords that follow the fenestrated capillaries

113
Q

2 types of cells of the parathyroid gland

A

Parathyroid chief cells and oxyphil cells

114
Q

What do parathyroid chief cells produce?

A

Parathormone (PTH)

115
Q

How does parathormone work?

A

Increases the blood levels of calcium

116
Q

Regulates PTH

A

Calcium blood levels

117
Q

Where are parathyroid chief cells derived from?

A

Neural crest

118
Q

Cell in parathyroid that has a large number of mitochondria in the cytoplams that stain intensely with acidic dyes

A

Oxyphil cells