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GENERAL FEATURES

Endocrine organs: Hypophysis

Thyroid glands

Adrenal (suprarenal glands) Hypothalamus

Pineal Body

Island of endocrine tissue:

Islets of Langerhans Isolated endocrine cells:

DNES

A .Component of the System

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Ductless

Invagination of epithelial surfaces pinch out

losing contact with parent epithelium

B .Origin

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C .Microscopic Structure

Numerous secretory cells:

cords, clumps, hollow

Contact with abundant

capillaries

Adrenal Cortex:Zona Fasciculata

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D .Secretion

Merocrine bloodstream

Product:Hormon

Peptide hormones

Steroid hormones

Others: enzymes, serum albumin

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E .Neuroendocrine System

Overlapping system that control cells, tissue and

organs

Master glands: Pituitary/ hypophysis

Controlled by Hypothalamus

Hypothalamic activity: controlled by

Neural connections with other parts of the nervous

systemNegative feedback from the hormones product by

pituitarys target

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THE COMPONENT PARTS OF THE PITUITARY AND

THEIR RELATION TO HYPOTHALAMUS

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HYPOPHYSIS/ PITUITARYSuspended by stalk from hypothalamus

In the sphenoid bone called sella turcicaBased on differences of embryonic origin, structure,

and function:

-Adenohypophysis (anterior)

-Neurohypophysis (posterior)

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DEVELOPMENT OF THE PITUITARY

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Adenohypophysis

Composed of cords glandular

epithelial cells separated by

the numerous sinusoidal

capillaries of the secondarycapillary plexus

Subdivision:

Pars distalis (pars anterior)

Pars tuberalis (superior)

Pars intermedia

Anterior Pituitary

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Pars Distalis, 2 type of cells:

Chromophobes (50%) Chromophils

Acidophils

Basophils

Pars Tuberalis Similar with pars distalis

Pars Intermedia

Rudimentary in human

Rathkes cysts

Melanotropes

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SUBDIVISIONS, BLOOD SUPPLY, AND

INNERVATION OF THE PITUITARY GLANDS

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Neurohypophysis

Contains abundant axons

whose cell bodies are

located mainly in thesupraoptic and

paraventricular nuclei of

the hypothalamus

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Subdivision:

Infundibulum

Infundibular stem (neural stalk)

Median eminence

Pars nervosa

COMPONENTS: Fenestrated capillary plexus

Surrounding axon terminals in pars nervosa

Pituicytes

Highly branched glial cells whose processes surround

and support the unmyelinated axons

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ADRENAL / SUPRARENAL

GLANDS

Divided by embryonic origin, structure, andfunction into:

Adrenal cortex

Adrenal medulla

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Adrenal Glands Blood Supply of The Adrenal

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A .Adrenal Cortex

Embryonic origin: From coelomic intermediate

mesoderm

Structure:

Zona glomerulosa

Zona fasciculataZona reticularis

Function:

Mineralocorticoids

GlucocorticoidsAdrenal androgens

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B .Adrenal Medulla

Embryonic origin: From neural crest

Structure:

Chromaffin cells/ pheochromocytes

Ganglion cells

Function:Epinephrine

Norepinephrine

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ISLET OF LANGERHANS

They appear as rounded clusters of cellsembedded within exocrine pancreatic tissue

Contain 4 major peptide hormone-secretingendocrine cell types:

A Cells (Alpha Cells) : glucagon

B Cells (Beta Cells) : insulin

D Cells (Delta Cells) : somatostatinF Cells (PP Cells) : pancreatic polypeptide

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Islet of Langerhans

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THYROID GLAND

Arises as an outpocketing of the endoderm liningthe floor of the embryonic pharynx

Store secretory product (thyroglobulin)

extracellularly in colloidThyroid follicular cells:

Inactive: squamous

During stimulation: columnar

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Function:

a. Synthesis and storage thyroglobulin

b. Uptake and oxidation of iodine

c. Iodination of thyroglobulin and formation of

thyroid hormone

d. Thyroid hormone secretion

e. Target and effects of thyroid hormones

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Thyroid Gland

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Thyroid Glands

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Thyroid Glands

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PARATHYROID GLANDS

Chief cells- Structure : polygonal

- Function : Parathyroid hormon

increasing of blood calcium

Oxyphyl cells

- Larger and less numerous than chief cells

- Function is not clearly

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PINEAL BODY

Brain sand ( corpora arenacea)

There are 2 types of cells :

Pinealocytes : melatonin

Astroglial cells (Interstitial cells)

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Pineal Gland