11

22

Endocrine system regulates metabolic Endocrine system regulates metabolic activities activities help in bring out homeostasis help in bring out homeostasis33

Nervous & endocrine systems functions in Nervous & endocrine systems functions in different way different way interact to modulate & interact to modulate & coordinate metabolic activities of bodycoordinate metabolic activities of body33

Secretory products/hormones secreted into:Secretory products/hormones secreted into:1, 21, 2

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

Rich in vascular supply, secreting cellsRich in vascular supply, secreting cells direct access to cappilllariesdirect access to cappilllaries22

33

44

1.1. DUCTLESS GLANDS (pituitary DUCTLESS GLANDS (pituitary gland/hypophysis, adrenal gland, gland/hypophysis, adrenal gland, parathyroid gland, thyroid gland, parathyroid gland, thyroid gland, pineal gland)pineal gland)2, 32, 3

2.2. UNICELLULAR ENDOCRINE CELLS UNICELLULAR ENDOCRINE CELLS form a diffuse endocrine system (e. g: form a diffuse endocrine system (e. g: In GI tract, conducting airways of In GI tract, conducting airways of lung)lung)2, 32, 3

55

Testes

Ovaries

Classic Endocrine GlandsClassic Endocrine Glands

66

77

Lying in sella turcicaLying in sella turcica22

Produces hormones responsible for Produces hormones responsible for regulating growth, reproduction & regulating growth, reproduction & metabolismmetabolism33

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

A.A. ADENOHYPOPHYSIS (anterior ADENOHYPOPHYSIS (anterior pituitary)pituitary) epithelial component : epithelial component :

- Pars distalis - Pars distalis anterior lobe anterior lobe- Pars intermedia- Pars intermedia- Pars tuberalis - Pars tuberalis

B.B. NEUROHYPOPHYSIS (posterior NEUROHYPOPHYSIS (posterior pituitary)pituitary) nervous component : nervous component :

- Pars nervosa (major part)- Pars nervosa (major part)- Infundibular stalk- Infundibular stalk- Median eminence - Median eminence

Posterior lobe Posterior lobe Pars intermedia + pars Pars intermedia + pars nervosa nervosa 22

88

99

Figure 18.6a, b

1010

75% of hypophysis75% of hypophysis11

Composed of cords of cells with large Composed of cords of cells with large sinusoidal cappilariessinusoidal cappilaries33

Endothelial lining of sinusoids Endothelial lining of sinusoids fenestrated fenestrated fascilitates diffusion of fascilitates diffusion of releasing factors & provides entry releasing factors & provides entry sites for secretionssites for secretions33

2 kind of cells base on affinity for 2 kind of cells base on affinity for dyes :dyes :1, 2, 31, 2, 3

1. Chromophobic cells1. Chromophobic cells2. Chromophilic cells :2. Chromophilic cells :

- Acidophilic cells- Acidophilic cells- Basophilic cells- Basophilic cells

1111

Most abundant cells in pars distalis3

Structure :2, 3

Large, round or ovoid cells Lage secretory granules stain

orange to red with eosin

2 KIND OF CELLS

Secretory granules stain with histological dyes stain with acid dyes or stain with basic dyes3

1212

o Secretory granules stain blue with basic dye3

o Located at periphery of pars distalis3

o Consist of 3 types of cells :2, 3

1313

Small, No granules2

Less cytoplasm than chromophils Fail to color with routine stains2, 3

Degranulated chromophilic A reservoir of chromophilic

cells2

1414

Non secretory, star shape cellsNon secretory, star shape cells Constitute large population of pars distalisConstitute large population of pars distalis Have long processes Have long processes form gap junction form gap junction Function not clear Function not clear

1515

Chromophilic Chromophilic

cellscells

Acidophilic Acidophilic cellscells

Somatotrope cellsSomatotrope cells

Mammotrope cellsMammotrope cells

Basophilic Basophilic cells cells

Corticotropes cellsCorticotropes cells

Thyrotropes cellsThyrotropes cells

Gonadotropes Gonadotropes cellscells

FSH FSH secreting secreting

cells cells

LH secreting LH secreting cellscells

Chromophobe cellsChromophobe cells

Folliculostellate cellsFolliculostellate cells

1616

Forms a sleeve, around infundibular stalkForms a sleeve, around infundibular stalk22

Longitudinally arranged cords of cuboidal to low collumnar epithelial cells separated Longitudinally arranged cords of cuboidal to low collumnar epithelial cells separated by sinusoidsby sinusoids1,2, 31,2, 3

Basophilic cytoplasm, small den Basophilic cytoplasm, small den se granules, with lipid droplets se granules, with lipid droplets33

No spesific hormone secretedNo spesific hormone secreted 2, 32, 3

1717

Rudimentary in humans, only Rudimentary in humans, only 2% of hypophysis2% of hypophysis22

Consist of :Consist of :2, 32, 3

1.1. Chromophobe cellsChromophobe cells

2.2. Basophil cells Basophil cells small granules small granules

3.3. Colloid-containing cysts Colloid-containing cysts lined lined by chromophobic or basophilic by chromophobic or basophilic cell (cuboidal cells)cell (cuboidal cells)

Function of cells is unknownFunction of cells is unknown1, 21, 2

1818

Develops from a downgrowth of Develops from a downgrowth of hypothalamus hypothalamus

Macroscopically Macroscopically consist of consist of ::22

1.1. Median EminenceMedian Eminence

2.2. Infudibular StalkInfudibular Stalk

3.3. Infundibular Process (pars nervosa)Infundibular Process (pars nervosa)

1919

Tecnically not endocrine Tecnically not endocrine glandsglands33

Hormones synthesized in Hormones synthesized in perikarya of neurons perikarya of neurons supraoptic & paraventicular supraoptic & paraventicular nuclei in hypothalamus nuclei in hypothalamus pass down axon pass down axon stored in stored in nerve terminals that form pars nerve terminals that form pars nervosanervosa22

Consist of unmyelinated nerve Consist of unmyelinated nerve fibers/axons fibers/axons forms forms hypothalamo-hypophyseal hypothalamo-hypophyseal tracttract1, 21, 2

2020

Axon contain Axon contain HERRING BODIES HERRING BODIES accumulation of dense accumulation of dense neurosecretory granulesneurosecretory granules2, 32, 3

Pituicytes :Pituicytes :1,1, 2, 32, 3

Scattered among nerve fibersScattered among nerve fibers 25% of pars nervosa25% of pars nervosa Only nuclei stain well enoughOnly nuclei stain well enough Vary in size & shapeVary in size & shape Equivalent to neuroglial cells of Equivalent to neuroglial cells of

CNS CNS supported axons in pars supported axons in pars nervosanervosa

Hormones stored & released from Hormones stored & released from pars nervosa :pars nervosa :22

- ADH / Vasopressin- ADH / Vasopressin- Oxytocin- Oxytocin

2121

2222

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

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

Consist of adrenal cortex & adrenal Consist of adrenal cortex & adrenal medullamedulla2, 32, 3

A yellow pheripheral layerA yellow pheripheral layer11

80-90% of organs80-90% of organs3 3

Parenchyma : continous cords of Parenchyma : continous cords of secretory cells, separated by blood secretory cells, separated by blood sinusoidssinusoids22

2323

2424

Subdivided into 3 layerSubdivided into 3 layer : :1, 21, 2

1. Outer zona glomerulosa1. Outer zona glomerulosa2. Middle zona Fasciculata2. Middle zona Fasciculata3. Inner zona reticularis3. Inner zona reticularis

1.1. Zona glomerulosaZona glomerulosa : :1, 2, 31, 2, 3

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

Small Collumnar cells arranged Small Collumnar cells arranged into arcadesinto arcades

Spherical, central nuclei & 1 or Spherical, central nuclei & 1 or 2 nucleoli2 nucleoli

Acidophilic cytoplasm Acidophilic cytoplasm SER SER >>, well develop golgi comp., >>, well develop golgi comp., short mitochondriashort mitochondria

2525

2.2. Zona Fasciculata :Zona Fasciculata :1, 21, 2

Widest zone of cortex Widest zone of cortex 65- 65-80% of organs80% of organs

Polyhedral Cells larger than in Polyhedral Cells larger than in other 2 zone other 2 zone arrange in radial arrange in radial collumscollums

Spherical & centrally nuclei, Spherical & centrally nuclei, binucleate binucleate

Cytoplasm with many lipid Cytoplasm with many lipid droplets droplets lipid eliminated during lipid eliminated during stainningstainningappear 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, Spherical mitochondria, extensive SER, some RER, extensive SER, some RER, lysosomeslysosomes

2626

3.3. Zona ReticularisZona Reticularis : :1, 2, 31, 2, 3

7% of organs 7% of organs A network of irregular A network of irregular

anastomosing cordsanastomosing cords Similar cells to Similar cells to

fasciculata except fasciculata except smallersmaller

Acidophilic cytoplasm, Acidophilic cytoplasm, contain fewer lipid contain fewer lipid dropletsdroplets

Nuclei stain more deeplyNuclei stain more deeply

2727

Hormones secreted by Hormones secreted by ::1, 21, 2

1.1. Zona glomerulosa : mineralcorticoids primarily Zona glomerulosa : mineralcorticoids primarily aldosteronealdosterone

2.2. Zona Fasciculata : glucocorticoids cortisone Zona Fasciculata : glucocorticoids cortisone and cortisoland cortisol

3.3. Zona reticularis : glucocorticoids cortisone Zona reticularis : glucocorticoids cortisone and cortisol (probably)and cortisol (probably)

Cells of adrenal cortex NOT store Cells of adrenal cortex NOT store secretory products in granules secretory products in granules synthesize & secrete steroid hormone synthesize & secrete steroid hormone only upon demandsonly upon demands11

2828

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

CHROMAFFIN CELLSCHROMAFFIN CELLS : :1, 21, 2

A large round or polyhedral cellsA 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 Granules may contain epinephrine or norepinephrine epinephrine or norepinephrine (20% of granules), ATP, (20% of granules), ATP, chromogranins (binding protein), chromogranins (binding protein), dopamine beta hidroxylase, dopamine beta hidroxylase, enkephalinsenkephalins

Well develop golgi comp., some Well develop golgi comp., some RER, numerous mitochondriaRER, numerous mitochondria

2929

Enclosed in Conn. Tissue Enclosed in Conn. Tissue capsulecapsule22

Consist of :Consist of :22

A.A. Follicles Follicles

B.B. ColloidColloid a gelatinous a gelatinous material inside folliclematerial inside follicle

Follicle :Follicle :22

Spherical structure, vary in Spherical structure, vary in diameterdiameter

Walls Walls Simple squamous Simple squamous epitheliumepithelium

3030

Principal (follicular) cells:Principal (follicular) cells:22

Mainly form wall of follicleMainly form wall of follicle Squamous to cuboidal or Squamous to cuboidal or

collumnar, depend on activity of collumnar, depend on activity of thyroidthyroid

Round to ovoid nuclei, centrally Round to ovoid nuclei, centrally placed, 2 nucleoliplaced, 2 nucleoli

Numerous small vesicles contain Numerous small vesicles contain thyroglobulinthyroglobulin

In great demand of thyroid In great demand of thyroid hormone, follicular cells extend hormone, follicular cells extend pseudopods into follicles pseudopods into follicles to to envelop & absorb colloid envelop & absorb colloid

Synthesized ThyroglobulinSynthesized Thyroglobulin

3131

3232

Parafollicular / C cells:Parafollicular / C cells:2, 32, 3

Present in follicular epith. in conn. Present in follicular epith. in conn. Tissue between folliclesTissue between follicles

2 or 3 times bigger than follicular 2 or 3 times bigger than follicular cells cells

Occur singly or groupOccur singly or group Pale cytoplasm, round nucleus, Pale cytoplasm, round nucleus,

moderate RER, elongated moderate RER, elongated mitochondriamitochondria

Dense secretory granules contain Dense secretory granules contain calcitonin (Thyrocalcitonin) calcitonin (Thyrocalcitonin)

3333

Structure :Structure :22

Surrounded by thin conn. tissue Surrounded by thin conn. tissue capsule capsule trabeculae/septa with trabeculae/septa with blood vessels,lymphatics & nerveblood vessels,lymphatics & nerve

Parenchymal consist of epithelial Parenchymal consist of epithelial cells cells 2 types of cells 2 types of cells

Contain 2 types of cells :Contain 2 types of cells :

1. Chief (principal) cells1. Chief (principal) cells

2. Oxyphil cells2. Oxyphil cells

3434

3535

1.1. Chief (principal) cells :Chief (principal) cells :2, 32, 3

More numerousMore numerous Slightly eosinophilic-stainningSlightly eosinophilic-stainning Contain granules Contain granules Round & centrally placed Round & centrally placed

vesicular nucleivesicular nuclei Juxtanuclear golgi complex, Juxtanuclear golgi complex,

elongated mitochondria, elongated mitochondria, abundant RERabundant RER

PreProparathyroid hormone PreProparathyroid hormone synthesize on ribosomes of synthesize on ribosomes of RERRER on golgi complex on golgi complex become parathyroid hormone become parathyroid hormone

3636

2.2. Oxyphil cells :Oxyphil cells :2, 32, 3

Only small part of cell Only small part of cell populationspopulations

Occur singly or in group Occur singly or in group Larger than chief cellsLarger than chief cells Cytoplasm stains intensely Cytoplasm stains intensely

with eosin (acidophil)with eosin (acidophil) More mitochondria, More mitochondria,

smaller golgi app. & little smaller golgi app. & little RERRER

Intermediate cells Intermediate cells in in active phase of chief cells active phase of chief cells

Function unknown Function unknown

3737

Cover by thin conn. tissue capsule Cover by thin conn. tissue capsule continous with continous with meningeal (pial) tissue meningeal (pial) tissue septa septa1, 21, 2

2 types of cells :2 types of cells :1, 2, 31, 2, 3

1. Pinealocytes1. Pinealocytes2. Glial / Intertitial cells2. Glial / Intertitial cells

A.A. Pinealocytes 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.B. Glial / intertitial cellsGlial / intertitial cells : :1, 21, 2

Fewer number than pinealocytes Fewer number than pinealocytes Nuclei smaller & stain more deeplyNuclei smaller & stain more deeply Long cytoplasmic process, regarded as a form of astrocyteLong cytoplasmic process, regarded as a form of astrocyte

3838

Corpora adranacea (brain sand) :Corpora adranacea (brain sand) :1, 21, 2

Concretions found in pineal gland of humansConcretions found in pineal gland of humans Irregularly shaped structures occur in capsule Irregularly shaped structures occur in capsule

& substance of gland& substance of gland Consist mainly calcium carbonate & Consist mainly calcium carbonate &

phosphatesphosphates Increased with age, function unknownIncreased with age, function unknown

3939

4040

Pancreatic islets : Pancreatic islets : 22

Scattered among Scattered among pancreatic acinipancreatic acini

Irregular, elongate masses Irregular, elongate masses of of pale stainning cellspale stainning cells

In ordinary sections In ordinary sections homogenous population of homogenous population of pale polygonal cellpale polygonal cell22

In elect. Micrograph & In elect. Micrograph & special stainningspecial stainning : :22

1.1. Alpha / A cellsAlpha / A cells2.2. Beta / B cellsBeta / B cells3.3. Delta / D cellsDelta / D cells4.4. PP cellsPP cells

4141

1.1. Alpha cells : Alpha cells : 22

20% of islet cells 20% of islet cells Periphery of isletsPeriphery of islets Contain large, dense, Contain large, dense,

spherical granulesspherical granules2.2. Beta cells :Beta cells :22

78% of islet cells78% of islet cells Locate near the center Locate near the center

of isletsof islets Secretory granules Secretory granules

smaller than alpha smaller than alpha cells, contain small, cells, contain small, dense crystals dense crystals

3.3. Delta & PP cells located Delta & PP cells located periphery of isletsperiphery of islets22

4242

CELL TYPES CELL TYPES HORMONAL HORMONAL SUBSTANCESSUBSTANCES

PRIMARY PRIMARY FUNCTIONFUNCTION

A (alpha) A (alpha) GlucagonGlucagon Increase blood sugarIncrease blood sugar

B (beta)B (beta) Insulin Insulin Decrease blood Decrease blood sugarsugar

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

PP PP Pancreatic Pancreatic PolypeptidePolypeptide

Opposes action of Opposes action of cholecystokinincholecystokinin

4343

1.1. Basic Histology Text & Atlas Basic Histology Text & Atlas , , 10th ed. 10th ed. , L. Carlos , L. Carlos Junquira MD, Jose Carneiro MD, Robert O. Junquira MD, Jose Carneiro MD, Robert O. Kelley PhD, Kelley PhD, Lange Medical Books, Mc Graw-Hill Lange Medical Books, Mc Graw-Hill , , 1995. Pp 403 – 430.1995. Pp 403 – 430.

2.2. Essentials of Human Histology, 2Essentials of Human Histology, 2ndnd Edition, Edition, William J. Krausse PhD, Little Brown & William J. Krausse PhD, Little Brown & Company (Inc), 1996. Pp 377-392Company (Inc), 1996. Pp 377-392

3.3. Color Textbook of Histologi, 2Color Textbook of Histologi, 2ndnd edition, Gartner edition, Gartner LP, Hiatt JL, WB Saunders Company, LP, Hiatt JL, WB Saunders Company, Philadelphia, Pennsylvania, 2001. Pp 301-324Philadelphia, Pennsylvania, 2001. Pp 301-324

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