HISTOLOGY OF SUPRA RENAL GLAND

HISTOLOGY OF SUPRA RENAL GLAND

IMAG0356_1IMAG0350_1

 

IDENTIFICATION POINTS

  • OUTER MOST CAPSULE WITH TRABACULAE.
  • CORTEX SHOWING ZONA GLOMERULOSA,ZONA FASICULATA AND ZONA RETICULARIS.
  • MEDULLA SHOWING SINUSOIDS AND SYMPATHETIC GANGLION CELLS.

INTRODUCTION

– SUPRA RENAL GLANDS ARE A PAIR OF ENDOCRINE GLANDS SITUATED IN THE POSTERIOR ABDOMINAL WALL ABOVE THE UPPER POLE OF BOTH KIDNEYS.

– AS THESE ARE LOCATED ABOVE THE KIDNEY, HENCE CALLED SUPRA RENAL GLAND.

– IN MANY ANIMALS THEY ARE FOUND ADJACENT TO THE KIDNEYS HENCE THEY ARE ALSO CALLED ADRENAL GLAND.

STRUCTURE

CORTEX:

SUPERFICIAL OUTER PART WHICH IS 10 TIMES WIDER THAN MEDULLA. IT CONSISTS OF THREE DIFFERENT LAYERS:-

1.ZONA GLOMERULOSA:

  • OUTER MOST LAYER OF CORTEX WHICH CONSTITUTES ABOUT 1/5th OF TOTAL CORTEX.

CELL SHAPE: POLYHEDRAL OR COLUMNAR.

ARRANGEMENT: ACINUS LIKE GROUPS OR INVERTED U-FORM OR HORSE-SHOE SHAPED.

CYTOPLASMIC NATURE: BASOPHILIC.

  • THESE CELLS CONTAIN PROMINENT SMALL NUCLEI WITH  RICH SMOOTH ENDOPLASMIC RETICULUM AND GOLGI COMPLEX. MITOCHONDRIA ARE ELONGATED IN NATURE.

2.ZONA FASICULATA:

  • INTERMEDIATE LAYER OF CORTEX, CONSTITUTES ABOUT 3/5th OF TOTAL CORTEX.

CELL SHAPE: POLYHEDRAL OR COLUMNAR.

ARRANGEMENT: CORD LIKE IN TWO ROWS.

CYTOPLASMIC NATURE: BASOPHILIC.

  • THESE CELLS ARE ALSO CALLED SPONGIOCYTES, CONTAIN LARGE PROMINENT NUCLEI WITH RICH SMOOTH ENDOPLASMIC RETICULUM. GOLGI COMPLEX ARE BEST DEVELOPED IN THE CELLS OF ZONA FASICULATA WITH SPHERICAL MITOCHONDRIA.
  • EXTENSIVELY VACUOLATED CYTOPLASM WITH STORAGE OF CHOLESTROL AND VIT-C.

3.ZONA RETICULARIS:

  • INNERMOST LAYER OF CORTEX, CONSTITUTES ABOUT 1/5th OF TOTAL CORTEX.

CELL SHAPE: POLYHEDRAL OR COLUMNAR.

ARRANGEMENT: NETWORK LIKE.

CYTOPLASMIC NATURE: OFTEN ACIDOPHILIC.

  • AS CELLS FORM NETWORK , IT IS CALLED ZONA RETICULOSA.
  • CELLS ARE RICH IN SMOOTH ENDOPLASMIC RETICULUM,GOLGI APPARATUS AND CONTAINS SMALL AMOUNT OF FAT IN IT.MITOCHONDRIA WITH TUBULAR CISTERNAE.

MEDULLA:

INNERMOST PART OF SUPRA RENAL GLAND, CONSTITUTES ABOUT 1/10th OF TOTAL GLAND.

CELL SHAPE: POLYHEDRAL OR COLUMNAR.

ARRANGEMENT: CLUMPS AND IRREGULAR CORDS WITH SINUSOIDS.

CYTOPLASMIC NATURE: BASOPHILIC.

  • THE CELLS OF MEDULLA ARE CONSIDERED AS THE MODIFIED POST GANGLIONIC SYMPATHETIC NEURONS.
  • THESE CELLS ARE RICH IN SECRETORY GRANULES WITH ABUNDANT ROUGH ENDOPLASMIC RETICULUM AND GOLGI COMPLEX.

FUNCTIONS:

  • ZONA GLOMERULOSA- SECRETE MINERALOCORTICOIDS. Eg: ALDOSTERONE AND 11-DEOXY-CORTICOSTERONE.
  • ZONA FASICULATA- SECRETE GLUCOCORTICOIDS. Eg: CORTICOSTERONE AND CORTISOL(HYDROCORTISONE).
  • ZONA RETICULARIS- SECRETE SEX HORMONES(ANDROGENS AND ESTROGENS) AND SMALL AMOUNT OF GLUCOCORTICOIDS.
  • CELLS OF ADRENAL MEDULLA- SECRETE CATECHOLAMINES(ADRENALINE,NORADRINALINE AND DOPAMINE).

THEY ACT AS NEUROTRANSMITTERS AND ALSO PLAY AN IMPORTANT ROLE IN CARDIAC FUNCTION AND MAINTENANCE OF NORMAL BLOOD PRESSURE.

CLINICAL:

  • HYPERSECRETION OF GLUCOCORTICOIDS CAUSES CUSHING’S SYNDROME.
  • HYPOSECRETION OF GLUCOCORTICOIDS CAUSES ADDISON’S DISEASE.
  • PHEOCHROMOCYTOMA IS A CONDITION  RESULTING DUE TO EXCESS SECRETION OF CATECHOLAMINES FROM MEDULLA.
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