Histologic structure of endocrine system

HISTOLOGIC HISTOLOGIC STRUCTURE OF STRUCTURE OF

ENDOCRINE SYSTEMENDOCRINE SYSTEM

DR. I WAYAN SUGIRITAMA,M.KesDR. I WAYAN SUGIRITAMA,M.KesHISTOLOGY DEPARTMENTHISTOLOGY DEPARTMENT

MEDICAL FACULTY OF MEDICAL FACULTY OF UDAYANA UNIVERSITYUDAYANA UNIVERSITY

[email protected]

HORMONE : organic chemical that HORMONE : organic chemical that liberate by endocrine cells into liberate by endocrine cells into vascular systemvascular system

TARGET ORGAN : tissue/organ on TARGET ORGAN : tissue/organ on which the hormones actwhich the hormones act

ENDOCRINE GLANDS : Contain cell ENDOCRINE GLANDS : Contain cell that produce hormone (that produce hormone (Pituitary, Pituitary, Adrenal, Thyroid, Parathyroid, Adrenal, Thyroid, Parathyroid, Islet Langerhan,s, and Pineal)Islet Langerhan,s, and Pineal)

ENDOCRINEENDOCRINE

GENERAL CHARACTERISTICSGENERAL CHARACTERISTICS

1.1. COMMONLY SAID THAT THEY COMMONLY SAID THAT THEY HAVE NO DUCTSHAVE NO DUCTS

2.2. RICH SUPPLY OF BLOOD VESSELSRICH SUPPLY OF BLOOD VESSELS

3.3. EACH GLAND SECRETE ONE/MORE EACH GLAND SECRETE ONE/MORE HORMONE HORMONE SPECIFIC EFFECT SPECIFIC EFFECT UPON ANOTHER TISSUE/ORGANUPON ANOTHER TISSUE/ORGAN

PITUTIARY/ HYPOPHYSIS GLAND

• Develop from different embryonic :– Adenohypophysis :

evagination oral ectoderm– Neurohypophysis : neural

ectoderm

• Connected to the brain by neural pathways

• Hormone secretion controlled by Hypothalamus

SUBDIVISION OF HYPOPHYSIS

• Adenohypophysis (anterior pitutiary)– Pars distalis (anterior)– Pars intermedia– Pars tuberalis

• Neurohypophysis (posterior pitutiary)– Median eminence– Infundibulum– Pars Nervosa

ADENOHYPOPHYSIS (Pars Distalis )

Chromophils (have an affinity for histological dyes) Acidhophil (granules stain

orange-red with eosin)Somatotrophs

somatotropin (GH)Mammotrophs Prolactin

Basophil (granule stain blue with basic dyes)CorticotrophsACTHThyrothropsTSHGonadothropsLH and

FSH

Chromophobes (do not take up stain) Degranulated chromophils

ADENOHYPOPHYSIS(Pars Intermedia and Pars Tuberalis)

PARS INTERMEDIA Between pars distalis-nervosa Cuboidal cell line, colloid

containing cysts (Rathke,s cysts)

Houses cord of basophils along networl of capillaries POMC α-MSH,corticotropin, β-lipoprotein,and β-endorphine

PARS TUBERALIS Surround hypophyseal stalk Highly vascularized by arteries

and hypophseal portal system along which longitudinal cords of cuboidal-low columnar epith.

Cells contain secretory granule (FSH?, LH?)

HYPOTHALAMOHYPOPHYSEAL TRACT

Unmyelinated axon (cell bodies in supraoptic and paraventricular nuclei of hypothalamus), enter the posterior pitutiary terminate in vicinity of capillaries

Nuclei sythezise ADH and oxytocin, and also neurohypophysin

NEUROHYPOPHYSIS

Pars nervosa technically is not endocrine gland

Hypothalamohypophyseal tract end in the pars nervosa and store the neurosecretions that are produce by cells bodies (hypothalamus)

Axon supported by pituicytes (glial-like cell)

Axon contain granule of vasopressin or oxytocin

Chrome-alum staining reveal Herring bodies (accumulation of neurosecretory granule)

HYPOPHYSIS=MASTER GLAND

ADRENAL GLAND

• Consist of two layer :– Adrenal cortex

• From coelomic intermediate mesoderm

– Adrenal medulla• From neural crest modified

sympathetic postganglionic neurons

Adrenal cortex• Zona glomerulosa

– Columnar/pyramidal cells are arranged in closely packed, rounded or arched clusters

– Mineralocorticoids(aldosterone)

• Zona fasciculata– Polyhedral cells arranged in straight

cords– Glucocorticoids (cortisone &cortisol)

and androgens

• Zona reticularis– Cells disposed in irregular cords

that form anatomozing network– Glucocorticoids and androgens

ADRENAL MEDULLA

• Parenchymal : polyhedral cells arranged in cords/ clumps and supported by reticular fiber network

• >> capillary supply

• >> secretory granules– epinephrine &– norepinephrine

THYROID GLAND

Thyroid follicle is the structural and functional unit

Connective tissue septa derived from the capsule invaded the parenchym

Secrete T3 and T4

PARENCHYM OF THYROID GLAND

FOLLICULAR CELLS• Range from squamous-low columnar• Numerous short villi that extend into

colloid• Round, ovoid nucleus, • Basophilic cytoplasm, rod-shape

mitochondria, supranuclear golgi comp. numerous small vesicle

• Hormone T4 and T3 stored in colloid, which bound to Thyroglobulin

PARENCHYME CELL OF THYROID GLANDPARAFOLLICULAR CELLS• Pale staining, lie cluster among

the follicular cells• 2-3 times larger than follicular

cells; 0,1% of epithelium• Round nucleus, moderate RER,

elongated mithocondria, well developed golgi compl. Small dense granule

• Secrete calcitonin

SYNTHESIS OF THYROID HORMONE

PARATHYROIDS GLAND• Parenchym : consist of chief

cells and oxyphill cells • Cells form the cords or cluster

surrounded by reticular fiber and rich capillary network

• Connective tissue in older adult :>> adipose cells (up to 60%)

• Secrete PTH calcium metabolism

PARENCHYM OF PARATHYROID GLAND

• CHIEF CELLS– Eosinophilic-staining– Contain secretory granules (PTH)– Juxtanuclear golgi complex,

elongated mitochondria and abundant RER

• OXYPHIL CELLS– More deeply stain with eosin– Less numerous , appear in group– More mitochondria, small golgi

app. And little RER– The inactive phase of Chief cells

PINEAL GLAND

• Cone-shape midline projection from roof of the diencephalons

• 5-8 mm X 3-5 mm (120 mg)• Covered by pia mater

capsule septaincomplete lobules

• Parenchym composed by : pinealocytes & interstitial cell

• Melatonine secretion are influenced by light and dark

PARENCHYME OF PINEAL GLAND

• Pinealocytes– Basophilic cells, with one. two

long processed– Nucleus spherical– Cytoplasm : SER, RER, small

golgi app., mitochondria and small secretory granule

– Produce Melatonin and serotonin

• Interstitial cells– Scattered trough pinealocytes– Deeply staining, with long

processed– Calcium and carbonate deposite

CORPORA ARENACEA (BRAIN SAND) >> older

ISLET OF LANGERHANS

• Appear as rounded clusters of cells within exocrine pancreatic tissue

• Each islet consists of lightly stained polygonal/ rounded cells arranged in cords separated by network of fenestrated blood capillaries

• Four type cells (A, B, D and F)• The B cells have irregular

granules (insulin )• Type A cell Glucagons