ENDOCRINE GLANDS II

WRITTEN BY

RAYAN S. ALBALLAA

PARATHYROID GLAND LOCATION :- THERE ARE 4 PARATHYROID GLANDS ATTACHED

TO THE POSTERIOR SURFACE OF THE THYROID GLAND , TWO ON EACH THYROID LOBE .

EACH PARATHYROID IS ENCLOSED IN A CT CAPSULE .

PARATHYROID GLAND THE CELLS OF THE PARATHYROID FORM

CLUSTERS OR CORDS OF EPITHELIAL CELLS AROUND FENESTRATED CAPILLARIES SUPPORTED BY RETICULAR FIBERS .

SECRETES PARATHYROID HORMONE WHICH MAINTAINS Ca++ LEVEL BY ACTING ON BONE , KIDNEY , & INTESTINE .

PARATHYROID GLAND COINTAINS TWO TYPES OF CELLS :-

1.CHIEF CELLS ARE NUMEROUS , SLIGHTLY EOSINOPHILIC ( ACIDOPHIHLIC ) SMALL CELLS WITH LARGE NUCLEI . HAVE

SECRETORY GRANULES CONTAINING PARATHYROID HORMONE .

2.OXYPHIL CELLS ARE FEWER , LARGER , ACIDOPHILIC , & MORE DEEPLY STAINED WITH EOSIN THAN CHIEF CELLS . THEY HAVE MORE MITOCHONDRIA THAN CHIEF CELLS . THEIR FUNCTION IS UNKNOWN .

ADRENAL GLAND ( SUPRARENAL )

THERE’S A LEFT & A RIGHT ADRENAL GLANDS LOCATED ON THE SUPERIOR POLE OF EACH KIDNEY EMBEDDED IN FAT & COVERED BY A CT CAPSULE .

ADRENAL GLAND

CONSISTS OF :-

1. OUTER CORTEX2. INNER MEDULLA

ADRENAL CORTEX

THE CORTEX CONSISTS OF 3 ZONES : 1. ZONA GLOMERULOSA ( OUTERMOST ) 2. ZONA FASCICULATA ( MIDDLE ) 3. ZONA RETICULARIS ( INNERMOST )

ADRENAL CORTEX

THE CELLS OF ALL ZONES OF THE CORTEX HAVE THE FEATURES OF STEROID SECRETING CELLS :

SPHERICAL MITOCHONDRIA EXTENSIVE SER NO SECRETORY GRANULES ( VESICLES ) LIPID DROPLETS IN THE CYTOPLASM

THEY SYNTHESIZE & SECRETE STEROID HORMONES .

ZONA GLOMERULOSA ( OUTERMOST ZONE )

SMALL ACIDOPHILIC COLUMNAR CELLS DARK-STAINING NUCLEI SOME LIPID DROPLETS IN THE CYTOPLASM THE CELLS FORM CORDS OR CLUSTERS ( GROUPS ) EXTENSIVE SMOOTH ENDOPLASMIC RETICULUM SECRETES MINERALOCORTICOIDS ( ALDOSTERONE )

NOTE : WRONG STATEMENT IN THE BOOK ABOUT RER P.318

ZONA FASCICULAT (MIDDLE ZONE )

LARGEST ZONE OF THE CORTEX THE CELLS FORM STRAIGHT RADIAL COLUMNS THE CELLS ARE CALLED SPONGIOCYTES MANY LIPID DROPLETS IN CYTOPLASM LIGHTLY ACIDOPHILIC ( VACUOLATED CYTOPLASM ) THE CELLS ARE LARGER THAN THOSE OF

GLEOMERULOSA CONTAINS SINUSOIDAL CAPILLARIES SECRETES GLUCOCORTICOIDS

ZONA RETICULARIS ( INNERMOST ZONE )

THE CELLS ARE SMALLER THAN THOSE OF FASCICULATA THE CELLS FORM ANASTMOSING CORDS DARKLY STAINING ACIDOPHILIC CELLS FEWER LIPID DROPLETS THAN FASCICULATA SECRETES SEX HORMONES ( ANDROGENS ) MAY SECRETE GLUCOCORTICOIDS

ADRENAL MEDULLA

THE ADRENAL MEDULLA IS NOT SEPARATED FROM THE CORTEX BY CT

THE CELLS OF THE ADRENAL MEDULLA HAVE THE FEATURES OF PROTEIN SECRETING CELLS

AS IN THE CORTEX , THE CAPILLARIES OF THE MEDULLA

ARE FENESTRATED

ADRENAL MEDULLA THE MEDULLA CONTAINS :-

MODIFIED SYMPATHETIC GANGLION CELLS ( WITHOUT AXONS OR DENDRITES ) CALLED CHROMAFFIN CELLS

THE CHROMAFFIN CELLS SYNTHESIZE & STORE THE HORMONE EPINEPHRINE & NOREPINEPHRINE IN CYTOPLAMIC GRANULES WHICH STAIN BROWN WHEN FIXED IN SALTS OF CHROMIC ACID

SYMPATHETIC GANGLION CELLS ARE ALSO FOUND