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 CORTEX 2.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