bbs ii slide histology of endocrine glands

(1)

1

••

Endocrine system regulates metabolic activities

help in bring out homeostasis

33

••

Nervous & endocrine systems functions in different

way

interact to modulate & coordinate metabolic

activities of body

33

••

Secretory products/hormones secreted into:

1, 21, 2 Blood or lymphatic circulation

Blood or lymphatic circulation Directly into intercellular space Directly into intercellular space

••

Rich in vascular supply, secreting cells

direct access

to cappilllaries

22

(2)

3

1.

DUCTLESS GLANDS (pituitary

gland/

gland/hypophysis

hypophysis, adrenal gland,

, adrenal gland,

parathyroid gland, thyroid gland, pineal

gland)

2, 32, 3

2.

UNICELLULAR ENDOCRINE CELLS

form a

diffuse endocrine system (e. g: In GI tract,

conducting airways of lung)

(3)

5

(4)

•• Lying in sella turcicaLying in sella turcica22

•• Produces hormones responsible for regulating Produces hormones responsible for regulating growth, reproduction & metabolism

growth, reproduction & metabolism33

•• Hypophysis subdivision :Hypophysis subdivision :1, 2, 31, 2, 3

A. ADENOHYPOPHYSIS (anterior pituitary)

epithelial component : epithelial component : -- Pars distalis Pars distalis anterior lobeanterior lobe -- Pars intermediaPars intermedia

-- Pars tuberalis Pars tuberalis

B. NEUROHYPOPHYSIS (posterior pituitary)

nervous component : nervous component : -- Pars nervosa (major part)Pars nervosa (major part) -- Infundibular stalkInfundibular stalk -- Median eminence Median eminence

•• Posterior lobe Posterior lobe Pars intermedia + pars nervosa Pars intermedia + pars nervosa

2 2

(5)

[image:5.612.127.488.96.365.2]

9 Figure 18.6a, b

•• 75% of hypophysis75% of hypophysis11

•• Composed of cords of cells with large Composed of cords of cells with large sinusoidal cappilaries

sinusoidal cappilaries33

•• Endothelial lining of sinusoids Endothelial lining of sinusoids fenestrated

fenestrated fascilitates diffusion of fascilitates diffusion of releasing factors & provides entry sites releasing factors & provides entry sites for secretions

for secretions33

•• 2 kind of cells base on affinity for dyes :2 kind of cells base on affinity for dyes :1, 1, 2, 3

2, 3

1. Chromophobic cells 1. Chromophobic cells 2. Chromophilic cells : 2. Chromophilic cells : -- Acidophilic cellsAcidophilic cells -- Basophilic cellsBasophilic cells

(6)

•

Most abundant cells in pars

distalis

3

•

Structure :

2, 3

Large, round or ovoid cells Lage secretory granules stain orange to red with eosin

•

2 KIND OF CELLS

11

Secretory granules stain with

histological dyes stain with

acid dyes or stain with basic dyes3

o Secretory granules stain blue with

basic dye3

o Located at periphery of pars distalis3

(7)

•

Small, No granules

2

•

Less cytoplasm than chromophils

Fail to color with routine stains

2, 3

•

Degranulated chromophilic

•

A reservoir of chromophilic cells

2

13

Non secretory, star shape cells

Constitute large population of pars distalis

Have long processes

form gap junction

Function not clear

(8)

Chromophilic Chromophilic cells cells Acidophilic Acidophilic cells cells Somatotrope Somatotrope cellscells

Mammotrope cells Mammotrope cells Basophilic Basophilic cells cells Corticotropes Corticotropes cellscells

Thyrotropes cells Thyrotropes cells Gonadotropes Gonadotropes cells cells FSH FSH secreting secreting cells cells LH secreting LH secreting cells cells Chromophobe

Chromophobe cellscells

Folliculostellate Folliculostellate cellscells

15

•• Forms a sleeve, around infundibular stalkForms a sleeve, around infundibular stalk22 •• Longitudinally arranged cords of cuboidal to Longitudinally arranged cords of cuboidal to

low collumnar epithelial cells separated by low collumnar epithelial cells separated by sinusoids

sinusoids1,2, 31,2, 3

•• Basophilic cytoplasm, small den Basophilic cytoplasm, small den se granules, with lipid droplets

se granules, with lipid droplets33

(9)

••

Rudimentary in humans, only 2%

of hypophysis

22

••

Consist of :

2, 32, 3 1.

1. Chromophobe cellsChromophobe cells 2.

2. Basophil cells Basophil cells small granulessmall granules 3.

3. ColloidColloid--containing cysts containing cysts lined by lined by chromophobic or basophilic cell chromophobic or basophilic cell (cuboidal cells)

(cuboidal cells)

••

Function of cells is unknown

1, 21, 2

17

••

Develops from a downgrowth of

hypothalamus

••

Macroscopically

consist of

consist of ::

22

1.

Median Eminence

2.

Infudibular Stalk

3.

Infundibular Process (pars nervosa)

(10)

••

Tecnically

Tecnically not endocrine glands

not endocrine glands

33

••

Hormones synthesized in

perikarya

perikarya of neurons

of neurons supraoptic

supraoptic

&

& paraventicular

paraventicular nuclei in

nuclei in

hypothalamus

pass down

axon

stored in nerve

terminals that form pars

nervosa

22

••

Consist of

Consist of unmyelinated

unmyelinated nerve

nerve

fibers/axons

forms

hypothalamo

hypothalamo--hypophyseal

hypophyseal tract

tract

1, 1, 2

2

19

•• Axon contain Axon contain HERRING BODIES

accumulation of dense neurosecretory accumulation of dense neurosecretory granules

granules2, 32, 3

•

Pituicytes :

1,2, 3

Scattered among nerve fibers Scattered among nerve fibers 25% of pars nervosa

25% of pars nervosa

Only nuclei stain well enough Only nuclei stain well enough Vary in size & shape

Vary in size & shape

Equivalent to neuroglial cells of CNS Equivalent to neuroglial cells of CNS supported axons in pars nervosa supported axons in pars nervosa

•• Hormones stored & released from pars Hormones stored & released from pars nervosa :

nervosa :22

(11)

21

•• A pair of flattened, triangular structA pair of flattened, triangular struct2, 32, 3

•• Surrounded by thick conn. Tissue capsule Surrounded by thick conn. Tissue capsule forms trabeculae

forms trabeculae

•• Consist of adrenal cortex & adrenal Consist of adrenal cortex & adrenal medulla

medulla2, 32, 3

•• A yellow pheripheral layerA yellow pheripheral layer11

•• 8080--90% of organs90% of organs3 3

•• Parenchyma : continous cords of secretory Parenchyma : continous cords of secretory cells, separated by blood sinusoids

cells, separated by blood sinusoids22

(12)

23

••

Subdivided into 3 layer

Subdivided into 3 layer ::

1, 21, 2

1. Outer zona glomerulosa

2. Middle zona Fasciculata

3. Inner zona reticularis

1. Zona glomerulosa

:

1, 2, 31, 2, 3

A narrow band beneath capsule, A narrow band beneath capsule, 15% of organs

15% of organs

Small Collumnar cells arranged Small Collumnar cells arranged into arcades

into arcades

Spherical, central nuclei & 1 or 2 Spherical, central nuclei & 1 or 2 nucleoli

nucleoli

Acidophilic cytoplasm

(13)

Polyhedral Cells larger than in other Polyhedral Cells larger than in other 2 zone

2 zone arrange in radial collumsarrange in radial collums Spherical & centrally nuclei, Spherical & centrally nuclei, binucleate

binucleate

Cytoplasm with many lipid droplets Cytoplasm with many lipid droplets

lipid eliminated during lipid eliminated during stainning

stainning appear vacuolated appear vacuolated cells called

cells called SPONGIOCYTESPONGIOCYTE

Lipid droplets contain neutral fat, Lipid droplets contain neutral fat, fatty acids, fatty acyl esters of fatty acids, fatty acyl esters of cholesterol

cholesterol precursor for precursor for synthesize steroid hormones synthesize steroid hormones Spherical mitochondria, extensive Spherical mitochondria, extensive SER, some RER, lysosomes

SER, some RER, lysosomes

25

3. Zona Reticularis :

1, 2, 3

7% of organs

A network of irregular

anastomosing cords

Similar cells to fasciculata

except smaller

Acidophilic cytoplasm,

contain fewer lipid droplets

Nuclei stain more deeply

(14)

••

Hormones secreted by

Hormones secreted by ::

1.

1. Zona glomerulosa : mineralcorticoids primarily

Zona glomerulosa : mineralcorticoids primarily

aldosterone

2.

2. Zona Fasciculata : glucocorticoids cortisone and

Zona Fasciculata : glucocorticoids cortisone and

cortisol

3.

3. Zona reticularis : glucocorticoids cortisone and

Zona reticularis : glucocorticoids cortisone and

cortisol (probably)

••

Cells of adrenal cortex NOT store secretory

products in granules

synthesize & secrete

steroid hormone only upon demands

11

27

•• Composed of Composed of Chromaffin cells & sympathetic ganglionic cells33

• CHROMAFFIN CELLS::1, 21, 2

A large round or polyhedral cells A large round or polyhedral cells Numerous brown granules Numerous brown granules treated with chromium salts treated with chromium salts (chromaffin reaction)

(chromaffin reaction)

Granules may contain epinephrine Granules may contain epinephrine or norepinephrine (20% of

or norepinephrine (20% of granules), ATP, chromogranins granules), ATP, chromogranins (binding protein), dopamine beta (binding protein), dopamine beta hidroxylase, enkephalins

hidroxylase, enkephalins

(15)

capsule

22

••

Consist of :

22

A.

A. Follicles

Follicles

B.

B. Colloid

Colloid

a gelatinous

material inside follicle

•

Follicle :

2

Spherical structure, vary in Spherical structure, vary in diameter

diameter Walls

Walls Simple squamous Simple squamous epithelium

epithelium

29

30

Transverse section (T: trachea, Tg: thyroid gland, Pg: parathyroid gland,

(16)

Mainly form wall of follicle Mainly form wall of follicle

Squamous to cuboidal or collumnar, Squamous to cuboidal or collumnar, depend on activity of thyroid

depend on activity of thyroid Round to ovoid nuclei, centrally Round to ovoid nuclei, centrally placed, 2 nucleoli

placed, 2 nucleoli

Numerous small vesicles contain Numerous small vesicles contain thyroglobulin

thyroglobulin

In great demand of thyroid hormone, In great demand of thyroid hormone, follicular cells extend pseudopods follicular cells extend pseudopods into follicles

into follicles to envelop & absorb to envelop & absorb colloid

colloid

Synthesized Thyroglobulin Synthesized Thyroglobulin

(17)

in conn. Tissue between

follicles

2 or 3 times bigger than

follicular cells

Occur singly or group

Pale cytoplasm, round

nucleus, moderate RER,

elongated mitochondria

Dense secretory granules

contain calcitonin

(Thyrocalcitonin)

33

••

Structure :

22

Surrounded by thin conn. tissue capsule Surrounded by thin conn. tissue capsule

trabeculae/septa with blood trabeculae/septa with blood vessels,lymphatics & nerve vessels,lymphatics & nerve

Parenchymal consist of epithelial cells Parenchymal consist of epithelial cells

2 types of cells 2 types of cells

••

Contain 2 types of cells :

1. Chief (principal) cells

2. Oxyphil cells

(18)

35

1. Chief (principal) cells :2, 3

More numerous More numerous Slightly eosinophilic

Slightly eosinophilic--stainningstainning Contain granules

Contain granules

Round & centrally placed Round & centrally placed vesicular nuclei

vesicular nuclei

Juxtanuclear golgi complex, Juxtanuclear golgi complex, elongated mitochondria, elongated mitochondria, abundant RER

abundant RER

(19)

populations populations

Occur singly or in group Occur singly or in group Larger than chief cells Larger than chief cells Cytoplasm stains intensely Cytoplasm stains intensely with eosin (acidophil) with eosin (acidophil)

More mitochondria, smaller More mitochondria, smaller golgi app. & little RER

golgi app. & little RER Intermediate cells

Intermediate cells in in

active phase of chief cells active phase of chief cells Function unknown Function unknown

37

•• Cover by thin conn. tissue capsule Cover by thin conn. tissue capsule continous with meningeal continous with meningeal (pial) tissue

(pial) tissue septasepta1, 21, 2

• 2 types of cells :1, 2, 3

1. Pinealocytes 1. Pinealocytes

2. Glial / Intertitial cells 2. Glial / Intertitial cells

A. Pinealocytes

–

–Basophilic cells Basophilic cells 2, 32, 3

–

–Large lobulated nuclei Large lobulated nuclei 1, 21, 2

–

–Produce melatonin & several other subtances Produce melatonin & several other subtances

B. Glial / intertitial cells:1, 2 Fewer number than pinealocytes Fewer number than pinealocytes Nuclei smaller & stain more deeply Nuclei smaller & stain more deeply

Long cytoplasmic process, regarded as a form of astrocyte Long cytoplasmic process, regarded as a form of astrocyte

(20)

Concretions found in pineal gland of humans

Irregularly shaped structures occur in capsule &

substance of gland

Consist mainly calcium carbonate & phosphates

Increased with age, function unknown

(21)

Scattered among pancreatic

acini

Irregular, elongate masses of

pale

pale stainning

stainning cells

cells

In ordinary sections

homogenous population of

pale polygonal cell

22

In elect. Micrograph & special

stainning

stainning ::

22

1.

1. Alpha / A cellsAlpha / A cells 2.

2. Beta / B cellsBeta / B cells 3.

3. Delta / D cellsDelta / D cells 4.

4. PP cellsPP cells

41

1.

Alpha cells :

2

20% of islet cells

Periphery of islets

Contain large, dense,

spherical granules

2.

Beta cells :

2

78% of islet cells

Locate near the center of

islets

Secretory

Secretory granules smaller

granules smaller

than alpha cells, contain

small, dense crystals

3.

Delta & PP cells located

periphery of islets

2

(22)

CELL TYPES

CELL TYPES HORMONAL HORMONAL

SUBSTANCES SUBSTANCES PRIMARY PRIMARY FUNCTION FUNCTION A (alpha)

A (alpha) GlucagonGlucagon Increase blood sugarIncrease blood sugar

B (beta)

B (beta) Insulin Insulin Decrease blood Decrease blood

sugar sugar D (delta)

D (delta) SomatostatinSomatostatin Inhibitor of hormone Inhibitor of hormone secretions

secretions

PP

PP Pancreatic Pancreatic

Polypeptide Polypeptide

Opposes action of Opposes action of cholecystokinin cholecystokinin

43

1.

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,

10th ed. 10th ed.

, L. Carlos Junquira

MD, Jose Carneiro MD, Robert O. Kelley PhD,

Lange Lange Medical Books, Mc Graw

Medical Books, Mc Graw--Hill Hill

, 1995. Pp 403

, 1995. Pp 403 –

– 430.

430.

2.

Essentials of Human Histology, 2

ndnd

Edition, William

J. Krausse PhD, Little Brown & Company (Inc), 1996.

Pp 377

Pp 377--392

392

3.

Color Textbook of Histologi, 2

ndnd

edition, Gartner LP,

Hiatt JL, WB Saunders Company, Philadelphia,

Pennsylvania, 2001. Pp 301