Endocrine Histo Flashcards
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
What do corticotropes produce?
Adrenocorticotropic hormone (ACTH)
26
What does ACTH act on?
The cells of the adrenal cortex
27
Controls the release of ACTH
Corticotropin-releasing hormone (CRH) released from the hypothalamus
28
2 main hormones secreted by gonadotropes
Follicle-stimulating hormone (FSH) and lutenizing hormone (LH)
29
Controls the secretion of the gonadotropes
Gonadotropin-releasing hormone released from the hypothalamus
30
What do thyrotropes produce?
Thyrotropic hormone (TSH)
31
Controls the release of TSH
TRH
32
Part of the pituitary derived from nerve tissue
Neurohypophysis
33
Regions of the neurohypophysis
Pars nervosa, infundibulum
34
Glial cells in the neurohypophysis
Pituicytes
35
What is secreted into the pars nervosa by the hypothalamus?
Oxytocin and anitduiretic hormone
36
Large distended axon terminals of these neurons can sometimes be visualized as what?
Herring bodies
37
What does the superior hypophyseal artery supply?
Pars tuberalis, infundibulum, median eminence, pars distalis
38
Most prominent feature of the hypophyseal blood supply
Hypophyseal portal system
39
What does the superior hypophyseal artery form upon arrival to the pituitary?
Primary capillary plexus
40
Where does blood go after the primary capillary plexus?
Into the hypophyseal portal veins, into the secondary capillary plexus in the pars distalis
41
Within which plexus do the hormones for the bloodstream exit the pituitary?
Secondary capillary plexus
42
Blood supply to the pars nervosa
Inferior hypophyseal artery
43
Unpaired pine-cone-shaped midline organ of the brain
Pineal gland
44
Where is the pineal gland located?
Posterior end of the third ventricle of the brain, covered by cerebral hemispheres
45
What does the pineal gland develop out of?
Outgrowth from the dicephalon
46
What covers the pineal gland?
Pia mater forms the capsule, septa extends into the gland fron this capsule
47
What are aggregates of calcuim phosphates found with the pineal gland?
Corpora arenacea, aka brain sand
48
Principle cells of the pineal gland
Pinealocytes
49
What do the spaces between the clusters of the pineal gland contain?
Axons, pinealocyte cell processes, blood vessels, corpora arenacea
50
Describe pinealocytes on microscope
Large euchromatic nuclei with a prominent nucleolus
51
What do pinealocytes secrete?
Melatonin
52
How does the information about the light/dark cycles reach the pineal gland?
Retinothalamic tract, connecting the suprachiasmic nucleus with the sympathetic neural tracts
53
How is the synthesis/secretion of melatonin controlled?
Norepinephrine released by the sympathetic neurons
54
What is the activity of melatonin?
Inhibits the steroidogenic activity of the gonads
55
Supporting cells of the pineal gland
Glial cells (interstitial cells)
56
Describe the glial cells of the pineal gland
Nuclei are smaller and more heterochromatic
57
Divisions of the adrenal gland
Cortex(yellow peripheral layer) and medulla(central reddish-brown layer)
58
Embryological origin of the cortex
Mesenchyme, mesodermal in origin
59
Embryological origin of the medulla
Neural crest cells, ectodermal in origin
60
Tissue of the capsule
Dense connective tissue with thin trabeculae into the parenchyma of the gland
61
Forms the majority of the adrenal gland
Cortex (90% of the gland)
62
Steriod-producing part of the gland
Cortex
63
What does the cortex produce?
Mineralocorticoids, glucocorticoids, some androgens
64
Characteristics of steriod-producing cells
Numerous lipid droplets, mitochondria with tubular cristae, abundant smooth ER
65
What do cortex cells do with steriod hormones?
Released immediately
66
Divisions of the adrenal cortex
Zona: glomerulosa, fasciculata, reticularis
67
Cell appearance of the zona glomerulosa
Closely packed cubodial/pyramidal cells, arranged into arched cords/curved columns, surrounded by numerous fenestrated sinusoidal capillaries
68
What do the cells of the zona glomerulosa secrete?
Mineralocorticoids
69
Purpose of mineralocorticoids
Regulate sodium and potassium honeostasis and water balance
70
Principle mineralocorticoid of the zona glomerulosa
Aldosterone (causes reabsorption of sodium)
71
Stimulates the zona glomerulosa to produce aldosterone
Angiotension II
72
Makes up the majority of the adrenal gland
Zona fasciculata
73
Describe the zona fasciculata
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
Large secretory cells in the zona fasciculata
Spongiocytes
75
Secretion of the spongiocytes
Mostly glucocorticoids
76
Role of glucocorticoids
Increase metabolism of glocus and fatty acids, depress the immune and inflammatory responses
77
How do glucocorticoids depress the immune and inflammatory responses?
Suppress the production of interleukin-1 and IL-2 by lymphocytes and macrophages, also supress lymphoblast mitosis within lymph nodes
78
What controls glucocorticoid production?
ACTH produced by the corticotropes of the anterior pituitary lobe. Necessary for cell growth and increased blow flow thru the adrenal gland
79
Innermost layer of the cortex
Zona reticularis
80
Appearance of the zona reticularis
Relatively small cells arranged into irregular cords that anastomose to form a network, contain fewer lipid droplets and stain more intensely with eosin
81
Contants of zona reticularis cells
Lipofuscin granules
82
What do the cells of the zona reticularis secrete?
Androgens and glucocorticoids
83
Composition of the adrenal medulla
Polyhedral cells arranged into clumps or cords supported by reticular fibers, with an extensive network of fenestrated capillaries
84
Principle secreting cells of the adrenal medulla
Chromaffin cells
85
Where are chromaffin cells derived from?
Neural crest cells, so they are modified postsynaptic neurons that lack axons
86
What is unique about the granules of the chromaffin cells?
Accumulate and store hormones
87
How to differentiate between norepinephrine and epinephrine cells in chromaffin cells?
Epi cells are smaller and more abundant. NE cells have larger secretory granules
88
Innervation of chromaffin cells
Synaptic nerve fibers
89
Causes the degranulation of chromaffin cells
Release of acetylcholine from the synaptic terminals
90
How are the hormones of the chromaffin cells delivered to the body?
Via the bloodstream thru fenestrated capillaries
91
Modulate the activity of chromaffin cells and innervate blood vessels within the medulla
Ganglion cells
92
Irrigates the adrenal gland capsule
Capsular arteries
93
Blood supply within the cortex
Cortical arteries that branch and form a dense network of fenestrated cortical sinusoidal capillaries
94
Blood supply within the adrenal medulla
Medullary arteries that form a dense network of fenestrated medullary sinusoidal capillaries AND the cortical capillaires
95
Recieves blood from smaller blood vessels withing the medulla
Adrenimedullary collecting veins
96
Drains the blood from the adrenal gland
Central adrenomedullary vein (IVC on right side, left renal vein on left side)
97
Main structural unit of the thyroid gland
Thyroid follicle
98
Structure of a thyroid follicle
Spherical structure forms by a layer of simple cuboidal follicular epithelium surrounding a cyst-like central cavity
99
Contents of thyroid follicle
Colloid
100
2 types of cells of the follicular epithelium
Follicular and parafollicular cells
101
Principle endocrine cells of thyroid gland
Follicular cells
102
Origin of thyroid follicular cells
Endodermal
103
2 main hormones synthesized by follicular cells
Thyroxine (T4) and Triiodothyronine (T3)
104
Synthesized in RER of follicular cells and is secreted into the lumen of the follicle
Thyroglobulin
105
How is iodide used in follicular cells?
Actively transported from blood into cytoplasm, iodine is oxidized to iodine and released into the colloid
106
How are T4 and T3 stored in the follicular cells?
Linked to thyroglobulin molecule to remain stored in cell
107
How are T4 and T3 released?
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
Main function of parafollicular cells
Synthesis of calcitonin
109
What does calcitonin do?
Lowers blood calcium levels by suppressing the resorptive activity of osteoclasts and promoting calcium deposition in bones by osteoblasts
110
Where are parafollicular cells derived from?
Neural crest
111
Small endocrine glands usually embedded with the thyroid
Parathyroid glands
112
Arrangement of parathyroid gland cells
Arranged into cords that follow the fenestrated capillaries
113
2 types of cells of the parathyroid gland
Parathyroid chief cells and oxyphil cells
114
What do parathyroid chief cells produce?
Parathormone (PTH)
115
How does parathormone work?
Increases the blood levels of calcium
116
Regulates PTH
Calcium blood levels
117
Where are parathyroid chief cells derived from?
Neural crest
118
Cell in parathyroid that has a large number of mitochondria in the cytoplams that stain intensely with acidic dyes
Oxyphil cells
