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Flashcards in endocrine system histo Deck (63):
1

Responsible for the synthesis and secretion of chemical messenger

endocrine glands

2

composed of islands of secretory cells of epithelial origin derived from any of the 3 primary germ layers.

endocrine glands

3

It has supporting tissues rich in blood and lymphatic capillaries

Ductless glands

endocrine glands

4

Hypophysis cerebri

A specialized appendage of the brain which secretes a variety of hormones.

Pituitary gland

5

is a small, slightly elongated organ buried in the sella turcica and is covered by the diaphragm sellae.

Pituitary gland

6

divides pituitary gland into anterior and posterior

residual lumen of Rathke’s pouch

7

anterior pituitary gland

(adenohypophysis / pars distalis)

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posterior pituitary gland

(neurohypophysis / pars nervosa)

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this vestigial cleft divides the anterior pituitary from the pars intermedia.

residual lumen of Rathke’s pouch

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An extension of the adenohypophysis surrounding the neural stalk

(PARS TUBERALIS.)

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The anterior pituitary arises from

the RATHKE’S POUCH

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parts/pars of Anterior lobe :

1) pars distalis
2) pars tuberalis

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parts Posterior lobe :

1) pars intermedia
2) pars nervosa

14

Located between the pars distalis and pars nervosa

Composed of a thin layer of cells and vesicles containing acidophilic colloidal substance

Parenchymal cells are known as MELANOTROPHES

pars intermedia

15

1) Hormones which act directly on non-endocrine tissues:

a) GH b) prolactin c) ADH d) oxytocin e) MSH

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Hormones which modulates the secretory activities of other endocrine glands (TROPHIC HORMONES):

a) TSH b) ACTH c) FSH d) LH

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Hormones which modulates the secretory activities of other endocrine glands

TROPHIC HORMONES

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-------- may be described as pituitary-dependent endocrine glands

The thyroid, adrenal cortex and gonads

19

WAYS OF CONTROL OF PITUITARY SECRETIONS

Releasing Factors
Feedback Mechanism

20

The anterior lobe constitutes how many percent of the pituitary gland.

75%

21

The parenchyma(pars distalis) is made up of separated from sinusoidal capillaries by a small amount of reticular fibers.

anastomosing cords and clusters of epithelial cells

22

Endocrine organs

1. Pituitary Gland
2. Thyroid Gland
3. Parathyroid gland
4. Adernal Gland
5. Paraganglia
6. Pancreas

23

anterior lobe
made up of secretory cells derived from Rathke's pouch, an embrologic extension of the primitive oral cavity.

adenohypophysis

24

the posterior lobe
is composed of neural tissue; it is a direct extension of the brain, and is attached to the hypothalamus by the pituitary stalk.

neurohypophysis

25

composed of round to polygonal epithelial cells arranged in cords and nests, amid a rich fibrovascular network. These cells release their granules in response to releasing factors elaborated in the hypothalamus.

pars distalis

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types of parenchymal cells based on staining reactions:

chromophils
chromophobes
gamma cells

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_____________ techniques can be used to classify the cells by their hormone contents

immunoperoxidase

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Located between the pars distalis and pars nervosa

Composed of a thin layer of cells and vesicles containing acidophilic colloidal substance

Parenchymal cells are known as MELANOTROPHES

pars intermedia

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It consists of supporting cells resembling neuroglial cells, the pituicytes and terminal portions of the axons of the supraoptic and paraventricular nuclei of the hypothalamus.

pars nervosa/neurophysis

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accumulations of neurosecretory materials in nerve terminals.

HERRING BODIES

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composed of unmyelinated, tangled nerve fibers that discharge ADH & oxytocin, produced in the hypothalamus and stored in Herring bodies, into blood stream.

Normal Posterior Pituitary Gland

32

HYPERPITUITARISM
(3)

1. Gigantism
2. Acromegaly
3. Hyperprolactinaemia

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cells that secrete CALCITONIN

PARAFOLLICULAR CELLS - secrete CALCITONIN

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important distinguishing histological feature of thyroid gland

Cuboidal epithelium with an orderly arrangement of the nuclei around the follicles -

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the structural unit of the gland compose the lobules.

THYROID FOLLICLES

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, which is filled with colloid representing the stored product of the follicular lining epithelium.

FOLLICULAR CAVITY

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FUNCTIONS OF THE THYROID GLAND

Synthesize, store and release hormones THYROXIN (T4) & TRIIODOTHYRONINE (T3) for regulation of metabolic rate

Elaboration of calcitonin by parafollicular (C) cells – lowers plasma calcium concentration

38

The parenchyma of parathyroid gland is composed of

masses and cords of epithelial cells

39

FUNCTIONS OF THE PARATHYROID

1) Essential for life; they elaborate parathormone which is important in the regulation of calcium metabolism.

2) Decreases the concentration of phosphatase.

3) With a direct effect on the ion transport in the kidney.

*Parathyroid responds directly to blood calcium level and are not under the control of other endocrine organs

40


A pair of triangular flattened yellowish organ embedded in the retroperitoneal adipose tissue. It is encapsulated and gives trabeculae into the cortex.

suprarenal/adrenal gland

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suprarenal gland outer __________

bright yellow cortex

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suprarenal gland inner _________

inner reddish brown zone

43

The adrenal glands are functionally and structurally 2 distinct parts:


1) Cortex / Inter-renal tissue
– mesodermal

2) Medulla / Chromaffin tissue
- ectodermal

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adrenal cortex 3 zones


Divided into 3 zones:

Zona glomerulosa – outer zone

2) Zona fasciculate – middle zone

3) Zona reticularis – inner zone

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Closely packed clusters and arcades of columnar cells arranged in hooked / horse shoe shaped slightly coiled columns

Zona glomerulosa

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Spheroidal nucleus; deeply stained with one or two nucleoli; acidophilic cytoplasm

Zona glomerulosa

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Secretes mineralocorticoid hormones (aldosterone & deoxycorticosterone) - for fluid & electrolyte balance

Zona glomerulosa

48

Composed of cell cords parallel to one another; usually one or two cells in width; separated by a longitudinally arranged sinusoidal capillaries
W/ vesicular nucleus and cytoplasm w/ abundant amount of lipid droplets (cholesterol, fatty acids & neutral fats).

Zona Fasciculata

49

Zone that Secretes glucocorticoids.

Zona Fasciculata

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Cells of zona fasciculata appear vacuolated and spongy, hence, they are called .

SPONGIOCYTES

51

Thinnest and least distinct

Cells are arranged in cords to form an anastomosing network.

The secretory cells produce the SEX HORMONES.

Zona Reticularis

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Closely packed clumps of secretory cells w/ numerous wide diameter capillaries.

W/ large vesicular nuclei and a strongly basophilic cytoplasm with fine chromaffin granules.

Granules become brown with potassium dichromate (Zenker’s fixative); secretory cells known also as chromaffin cells

adrenal medulla

53

- brown coloration of the granules when exposed to chromium salts due to the oxidation of epinephrine and norepinephrine within the granules of the cells.

CHROMAFFIN / PHEOCHROME REACTION

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Cells containing -------------- exhibit a stronger positive chromaffin reaction than adrenalin containing cells (epinephrocytes)

noradrenalin (norepinephrocytes)

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On E/M, the most characteristic feature of adrenal medulla is the -----------

presence of numerous membrane bound dense granules.

56

Widely scattered groups of cells that are similar to the medullary cells of the adrenal gland (chromaffin cells).

Cells of the paraganglia and cells of the adrenal medulla (“CHROMAFFIN SYSTEM”).



paraganglia

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(lumbar aortic paraganglia)

Paired para-aortic bodies of Zukerkandle

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Component cells of paraganglia are ----------------- and give positive pheochrome reaction.

“CHROMAFFIN CELLS”

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The endocrine portion of the pancreas are known as the

ISLET OF LANGERHANS

60

3 types of secretory cells with Mallory-Azan stain:


alpha cells
beta cells
delta cells

61

3 types of secretory cells with Mallory-Azan stain

large granules; colored brilliant red; less numerous, found in the periphery of the islet.
secrete glucagon

1) ALPHA (A cells)

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3 types of secretory cells with Mallory-Azan stain

smaller cells; located in the interior of the islet; stains brown with Mallory Azan.
60-90% of all islet cells.
synthesize insulin

2) BETA cells

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3 types of secretory cells with Mallory-Azan stain

w/ blue staining granules by Mallory-Azan stain.
secrete somatostatin

3) DELTA cells

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