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Test 4 Histology > Endocrine System > Flashcards

Endocrine System Flashcards

1
Q

7 parts/organs glands of endocrine system?

A
  1. Pituitary= adenohypophysis
  2. adrenal=hypophysis
  3. Pineal gland
  4. Thyroid
  5. Paraythyroid
  6. Islet of langerhans
  7. Diffuse neuroendocrine system
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2
Q

Location of pituitary gland? Other name?

A

Below the hypothalamus attached by INFUNDIBULUM.
Also functionally attached to hypothalamus.
AKA hypophysis

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3
Q

Pituitary divisions (formal names) and their embryological origin.

A 
Adenohypophysis= Anterior. From Rathke's pouch (ectoderm of stomodeum= oral cavity) /3 parts
Neurohypophysis = posterior. From neuroectoderm /2 parts
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4
Q

Adenohypophysis- parts?

A

Anterior pituitary- 3 parts

  1. Pars distalis
  2. pars intermedia
  3. Pars tuberalis
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5
Q

Neurohypophysis- Parts

A
  1. Infundibulum (continuous with hypothalamus)
  2. Pars nervosa (main body)
  3. hypothalamohypophyseal tract
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6
Q

Anterior lobe of pituitary **according to Turek notes, not BRS

A

Pars distalis (from adenohypophysis) + pars tuberalis (from adenohypophysis)

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7
Q

Posterior lobe of pituitary **according to Turek notes, not BRS

A

Pars intermedia (from adenohypophysis) + pars nervosa (from neurohypophysis)

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8
Q

T/F Glands in the endocrine system have ducts

A

FALSE- Ductless glands

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9
Q

Regulation of pituitary gland

A

Peptide hormones from the hypothalamus are released into the capillaries of the infundibulum and travel to the pituitary to stimulate or inhibit release of of hormones from the ANTERIOR PITUITARY

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10
Q

Hormones that regulate pituitary hormones

A 
Thyrotropin
Gonadotropin
Somatostatin
Growth Hormone
Corticotropin
Inhibitor of prolactin release (dopamine)
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11
Q

Pars distalis- structural components

A

connective tissue capsule and framework.
Hormones (from hypothalamus) enter pars distalis via secondary capillary plexus exit from the fenestrated capillaries and act on parenchymal cells.

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12
Q

Infundibulum- parts

A

Median eminence + stem

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13
Q

Blood route through pituitary

A

2 Main Arteries
(R&L) Superior hypophyseal a. = infundibulum(=median eminence + stem)
(R&L) Inferior hypophyseal a. = pars nervosa

Superior hypophyseal a –> primary capillary plexus (in INFUNDIBULUM) –>hypophyseal portal veins (descend through infundibulum to adenohypophysis, located in pars tuberalis) –> secondary capillary plexus (pars distalis)

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14
Q

Types of cells in pars distalis

A

Chromophils (acidophils (x2) and basophils(x3)) and chromophobes (3- degranulated, undiffer, CT/Follicular)

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15
Q

Chromophobes- general characteristic–types?

A

Parenchymal cells in the pars distalis of pituitary. Stain poorly. Few to no granules.
Types:
1. Undifferentiated
2. Degranulated- few granules
3. CT/Follicular- form stromal network to support chromophil cells.
??May contain acidophilic staining chromophiles???

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16
Q

Acidophils-

  1. staining
  2. Cell types?
  3. basic characteristics?
A
  1. Do not stain with PAS. Stain with eosin and orange G.
  2. Somatotrophs and Mammotrophs
  3. smaller than basophils. Release peptide hormone
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17
Q

Somatotrophs

  1. Location
  2. Secretion
  3. Function
  4. Regulated by?
A
  1. acidophilic cells of pars distalis
  2. Somatotropin= Growth Hormone
  3. Increases metabolism in most cells, stimulates production of liver somatomedins (insulin-like growth factors)–> long bone and epiphyseal plate growth
  4. ——somatostatin (growth hormone inhibiting factor)
    ++++++Growth hormone releasing factor
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18
Q

What supports chromophils?

A

Chromophils= pars distalis

CT/Follicular cells are chromophobes that create stromal network to support. Some phagocytic action.

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19
Q

Mammotrophs

  1. Location
  2. Secretion
  3. Function
  4. Regulated by?
A
  1. acidophilic cells of pars distalis (in pit)
  2. prolactin
  3. stimulates and maintains lactation
  4. Lactation increases number.
    +++++Thyrotropin-releasing factor (TRF)
    —–Prolactin inhibiting factor (dopamine)
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20
Q

Basophilic cells

  1. staining
  2. cell types?
  3. general characteristics?
A
  1. PAS positive. Basophilic staining
  2. (3 types) Corticotrophs, gonadotrophs, thyrotrophs
  3. Larger than acidophils, fewer granules
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21
Q

Gonadotrophs

  1. Location
  2. Secretion
  3. Function
  4. Regulated by?
A
  1. pars distalis of pituitary
  2. FSH, LH (also called interstitial cell stimulating hormone)
  3. FSH- a) stimulates dev of ovarian follicles and stimulates sertoli cells to produce androgen binding protein
    LH- stimulates steroidogenesis in ovarian follicles and corpus luteum. Regulator of leydig cells (testosterone pdt)
  4. stimulated by gonadotropin releasing hormone (GnRH)
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22
Q

Corticotrophs

  1. Location
  2. Secretion
  3. Function
  4. Regulated by?
A
  1. pars distalis of pituitary
  2. ACTH (Adrenocorticotropic hormone) and LPH (lipotropic hormone)
  3. ACTH- stimulates growth and steroid synthesis in adrenal gland (zona reticularis, fasiculata, and glomerulosa=all of adrenal cortex)
    LPH- precursor of b-endorphin
  4. CRH- corticotropin releasing hormone
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23
Q

Thyrotrophs

  1. Location
  2. Secretion
  3. Function
  4. Regulated by?
A
  1. pars distalis of pituitary (only 5% of cells)
  2. TSH
  3. TSH= causes thyroid to make T3 and T4
  4. Thyrotropin releasing hormone
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24
Q

Thyrotropin releasing hormone regulates?

A
  1. prolactin release from mammotrophs (acidophilic cell of pars distalis)
  2. TSH release from thyrotrophs (basophilic cell of pars distalis)
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25
Q

Paracrine regulation of pars distalis (not in notes)

  1. Cell type?
  2. Function(s)
A
  1. folliculostellate cells between the chromophobes and chromophils. form gap junctions with other folliculostellate cells.
  2. Regulate hormone production in pars distalis via production of paracrine peptides
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26
Q

Pars Nervosa Contents

A
  1. Has the distal ends of axons (NON MYELINATED) from hypothalamus with their herring bodies
  2. Pituicytes (25% of content in pars nervosa)
  3. fenestrated capillaries (located near the neuron ends)
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27
Q

Herring bodies–

  1. What are they? Where are they found?
  2. Cell bodies of (1) are located…?
A
  1. Accumulation of neurosecretory granules in non-myelinated axons in the pars nervosa of pituitary .
  2. paraventricular and suproptic nuclei of the hypothalamus
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28
Q

Pituicytes

A

25% of pars nervosa
astrocyte-like glial cells–SUPPORT AXONS IN PARS NERVOSA.
contain glial fibrillary acidic proteins(GFAP- type of intermediate filament, works with vimentin), lipid droplets, and pigments.

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29
Q

Function of pars nervosa?

A

Hypothalamic axons release oxytocin and ADH near capillary plexus.

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30
Q

Oxytocin

  1. production and release?
  2. function
A
  1. produced in paraventricular nucleus (some made in supraoptic nucleus) of hypothalamus and released by axons located in the pars nervosa of the pituitary.
  2. stimulates milk ejection and uterine contractions during childbirth
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31
Q

ADH

  1. production and release?
  2. function
A
  1. produced mainly in supraoptic nucleus (some in para ventricular nucleus) and released by axons located in pars nervosa of hypothalamus.
  2. Stimulates water reabsorption by the renal medullary collecting ducts
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32
Q

hypothalamohypophyseal tract

A

part of the neurophysis

transports ADH and Oxytocin (using neurophysin) and ATP to pars nervosa

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33
Q

Neurophysin

A

Binding/carrier protein for oxytocin and ADH. Moves them from cell bodies to the axon terminals in the pars nervosa of the pars nervosa (of posterior pituitary)

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34
Q

pars intermedia contents

A
  1. basophilic and chromophobic cells,

2. Rathke’s cysts= cuboidal lined epithelial cavities

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35
Q

Pars intermedia function

A
  1. basophilic cells (which can extend into pars nervosa) secrete pro-hormone proopiomelanocortin (POMC)
    POMC cleaved into melanocyte stimulating hormone = regulator of inflammatory response and fat storage
36
Q

Function of supraoptic nucleus vs para ventricular nucleus (of hypothalamus)

A

Supraoptic- mainly ADH production

Paraventricular nucleus- mainly oxytocin production

37
Q

Pars tuberalis

A

surrounds hypophyseal stalk

Cords of mainly cuboidal basophilic cells along capillary network.

38
Q

Acromegaly

A

excessive growth hormone (somatotrophs=acidophils of pars distalis)

39
Q

Prolactin secreting tumors

A

no ovulation= infertility

40
Q

Most common cause of hypopituitarism in adults

A

pituitary tumors/adenoma

41
Q

Primary pituitary destruction

A

= intrinsic pit destruction
hormone secreting cells in anterior pituitary are destroyed
level of destruction varies.

42
Q

Poor anterior lobe function

A

failure of lactation, amenorrhea, poor thyroid function, adrenal insufficiency

43
Q

Posterior lobe insufficiency

A

diabetes insipidus= polyuria, polydipsia
No water reabsorption
KNOW THIS (BRS)**

44
Q

Pineal gland-
1-3. facts about structure/location
4. innervation
5. cell characteristics

A
  1. covered by pia matter.
  2. NO BBB
  3. Capsule (from pia mater) with trabecula that divide it into lobes
  4. post ganglionic sympathetic nerves from superior cervical ganglion
  5. cells are basophilic with irregular nuclei and distinct nucleoli
45
Q

Pineal gland

contents & function & regulation

A
  1. pinealocytes-make melatonin= regulation of sleep cyclen (and serotonin during day, according to BRS)
  2. glial cells (interstitial cells)
  3. corpora arenacea= calcium phosphate/carbonate
  4. External lighting (signals from retinal neurons) inhibit secretion of melatonin
46
Q

Pinealocytes

  1. production
  2. regulation
A
  1. Make melatonin

2. External light inhibits melatonin secretion

47
Q

Pineal gland tumor

A

restrict flow of CSF through aqueduct of sylvius–>hydrocephalus

48
Q

thyroid gland

  1. Embryo (why!?)
  2. Basic structure
A
  1. Endoderm of the cephalic portion of the alimentary canal

2. two lobes connected by isthmus

49
Q

Thyroid lobe-

  1. basic structure
  2. Cell types
  3. Active vs inactive epithelium?
A

Lobe is made of follicles that have a SIMPLE CUBOIDAL epithelium = follicular cells (aka principal cells) .
.
Active- more columnar looking
Inactive- more squamous looking
Basal lamina separates CT and follicular cells. CT has lymphatic and capillary network (fenestrated)

50
Q

Thyroid follicle

  1. structure
  2. lining
  3. function
A
  1. Filled with acidophilic colloid (iodinated thyroglobulin—inactive)
  2. Lined by follicular cells. Parafollicular cells are on same side as basal lamina, but do not make contact with colloid.
  3. Synthesize, store and release thyroid hormones
51
Q

Parafollicular cells

  1. AKA? location?
  2. Produce/release
  3. Function?
  4. Regulation?
A
  1. C-cells. in follicle of thyroid (not in contact with colloid)
  2. Release calcitonin into follicular epithelium or between follicles
  3. calcitonin- prevent bone resorption (inhibits osteoclast activity) Minor role in regulating calcium resorption
  4. High blood calcium stimulates secretion, low blood calcium inhibits secretion.
52
Q

Follicular cells

  1. structure
  2. organelles
  3. secretions
  4. Regulation
  5. apical vs basal side?
A
  1. Normally cuboidal, columnar when active, squamous when inactive (so when are they cuboidal?!). short blunt microvilli on side of colloid.
  2. large rER, supranuclear golgi complex, lysosomes and mitochondria
  3. Synthesis and release of T3/T4
  4. TSH bind G-protein linked receptors on basal surface of follicular cells.
  5. Apical= facing colloid, short microvilli;
    Basal= close to fenestrated capillaries (where T3/T4 is released)
53
Q

Thyroid hormone production

A

occurs in follicular cells of thyroid gland.

  1. Thyroglubulin is made and glycosylated in rER and golgi.
  2. Iodide is ACTIVELY transported into cytosol and oxidized in cytoplasm. It enters colloid and iodinates tyrosine residue on thyroglobulin. Then it chills there until needed.
54
Q

Export of thyroid hormone

A
  1. Stimulated by TSH (from ant pit) binding g-protein receptor on follicular cell basal membrane.
  2. On apical surface, a colloid droplet is endocytosed and fuses with lysosome.
  3. Lysosome digests and releases T3/T4 which exit via basal side.
55
Q

Thyroxine vs triiodothyronine vs thyroglobulin?

A

T3=triiodothyronine
T4= thryoxine
Thyroglobulin- pre-cursor to thyroid (before iodination)

56
Q

Function of thyroid hormone?

A
  • stimulates overall increase in metabolism= heat.
  • stimulates transcription of certain genes
  • INCREASE carb metabolism, fatty acid synthesis
  • DECREASE cholest, phospholipid, TAG synthesis
57
Q

Hyperthyroidism symptoms.

A

weight loss, increased heart rate, metabolism, respiraiton and appetite.
can cause muscle tremors, tiredness, frequent or excessive menstrual bleeding

58
Q

Follicular hyperplasia

  1. what is it?
  2. cause?
A
  1. Swollen thyroid= goiter
  2. iodine deficiency= low T3/T4 –> increased TSH –> follicular hyperplasia
    (thyroid makes stuff and puts it in colloid, but can’t iodinate it so it’s there forever)
  • *not associated with hypo/hyper thyroidism.
  • *treated with iodine.
59
Q

grave’s disease

A

Immunological disease that makes Ig similar to TSH= hyperthyrdoisism

60
Q

Hashimoto’s disease

A

autoimmune destruction of thyroid= hypothyroidism. Germinal centers made of lymphocytes.
Thyroid peroxidase antibodies produced

61
Q

Prevalence of thyroid cancer in men vs women

A

women x4

62
Q

Myxedema

A

Can occur in hyper or hypo thyroidism

localized skin swelling

63
Q

Parathyroid gland

  1. location
  2. gland characteristics
  3. types of cells
  4. blood supply
A
  1. Behind thyroid (4 glands)
  2. Each gland has its own capsule that create septa
  3. Principal (chief) cells and oxyphil cells
  4. blood vessels run in septa
64
Q

Principal cell/Chief cell

  1. production
  2. characteristics
  3. regulation
A
  1. Parathyroid hormone
  2. irregular granules
  3. inhibited by high blood Ca+2
65
Q

Oxyphil cells

  1. characteristics
  2. Function
  3. relation to age?
A
  1. larger, eosinophilic (due to mitochondria)
  2. unknown function,
  3. appear after puberty and increase with age
66
Q

hyperparathyroidism

  1. causes (most common)
  2. Symtpoms
A
  1. adenoma (80%), carcinoma (1-2%) and hyperplasia (15)
  2. high blood calcium, low PO4. Bone cysts can develop, rubbery bones, kidney stones, pancreatitis, peptic ulcers and hypertension
67
Q

PTH -3 distinct functions to accomplish goal

A

All increase calcium levels

  1. calcified bone matrix is resorbed)
  2. increased calcium resorption in kidney distal tubule, increased phosphate secretion
  3. Stimulates Vit D synth–>increased synth of calcium binding proteins–> increased calcium absorption in intestines
68
Q

Hypoparathyroidism

A

decreased serum Ca and increased PO4

Tetany, muscle cramps, jaw locks, exaggerated tendon reflexes

69
Q

Adrenal glands

  1. structural characteristics
  2. embryological origin
A
  1. collagenous capsule embedded in fat-medulla and cortex
  2. Medulla= from ectoderm neural crest cells
    Cortex= mesoderm
70
Q

Adrenal cortex

A

3 zones of adrenal cortex (outside–>inside)
zona glomerulosa, zona fasciculata, and zona reticularis

Synthesize and secrete hormones—they are NOT stored

71
Q

Zona glomerulosa

  1. secretion
  2. regulation
  3. cell characteristics
  4. blood supply
A
  1. mineralocorticoids= aldosterone
  2. stimulated by angiotensin II and ACTH
  3. cells have lots of sER and mito with shelf-like cristae
  4. fenestrated capillary network
72
Q

Zona fasiculata

  1. secretion
  2. regulation
  3. cell characteristics
  4. blood supply
A
  1. Glucocorticoids= cortisol, corticosterone
  2. ACTH stimulates production/secretion
  3. Cell columns with sinusoidal capillaries perpendicular to capsule. Cells are called spongiocytes due to extensive lipid droplets. Mitochondria are spherical with tubular and vesicular cristae. contain LIPOFUSCIN pigment granules
  4. discontinuous fenestrated capillaries
73
Q

Zona Reticularis

  1. secretion
  2. regulation
  3. cell characteristics
  4. blood supply
A
  1. gonadocorticoids= DHEA and adrostenedione
  2. ACTH stimulates
  3. arranged in anastomosing cords
  4. discontinuous fenestrated capillaries
74
Q

lipofuscin pigment granules can be found?

A

in zona fasciculata and reticularis of adrenal cortex.

75
Q

Cells of adrenal medulla

A
  1. chromaffin cells

2. sympathetic ganglion cells

76
Q

Chromaffin cells

  1. function
  2. staining
  3. arrangement
  4. characteristics
A

(in adrenal medulla)

  1. Synthesize, store and secrete catecholamines= epinephrine and norepinephrine
  2. Stain with chromaffin salts
  3. arranged in short irregular cords with extensive capillary network –reticular fiber support
  4. Granules containing: catecholamine, ATP, enkephalins, chromogranins
77
Q

Chromogranins

A

binding proteins for epinephrine and norepinephrine that are found within the granules of chromaffin cells in the adrenal medulla

78
Q

Chromaffin cell activation

A
  1. emotional stimuli mediated by the preganglionic sympathetic fibers innervating the chromaffin cells.
79
Q

Blood supply of adrenal medulla

A

Venous= rich in hormones, reaches via fenestrated capillaries going through the cortex
Arterial= fenestrated network from capsular arteries
Medullary veins join to make suprarenal vein.

80
Q

Pheochromocytoma

A

Tumor of the adrenal medulla that causes hyperglycemia and transient BP elevations. most common adrenal tumor in adults

81
Q

Most common adrenal tumor in adults? children?

A 
pheochromocytoma= adults
neuroblastoma= children
82
Q

Neuroblastoma

A

tumor in adrenal gland of children, no effect on BP

83
Q

Cushing syndrome

A

excess cortisol secretion

can cause hirsutism= male hair

84
Q

Conn’s Syndrome

A

Excess Aldosterone production= increased H2O retention–>hypertension and hypokalemia

85
Q

Addison’s disease

A

Adrenocortical insufficiency= weakness, nausea, weight loss

High ACTH levels, causes hyperpigmentation

86
Q

Waterhouse-friderichsen syndrome

A

Acute cortical destruction. meningococcal sepsis, endotoxic shock.

Test 4 Histology (3 decks)

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