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HISTOLOGY OF URINARY BLADDER

HISTOLOGY OF URINARY BLADDER

IMAG0377_1IMAG0373_1

IDENTIFICATION POINTS

  • MUCOSA LINED BY TRANSITIONAL EPITHELIUM.
  • SUBMUCOSA IS ABSENT.
  • MUSCULAR LAYER CONTAINING DETRUSOR MUSCLES.

INTRODUCTION

– IT IS A MUSCULAR BAG LIKE STRUCTURE WHICH TEMPORARILY STORES URINE FOR VOIDING.

– NORMAL STORING CAPACITY IS 200-300ml.

STRUCTURE

MUCOSA:

INNER MOST LAYER OF URINARY BLADDER LINED BY TRANSITIONAL EPITHELIUM WITH LAMINA PROPRIA RICH IN BLOOD VESSELS UNDERNEATH IT. MUCOSA IS THROWN INTO MANY FOLDS WHICH EXPANDS TO COLLECT MORE QUANTITY OF URINE WITHIN THE BLADDER.

MUSCULAR LAYER:

IRREGULAR CONSISTING OF INNER LONGITUDINAL,MIDDLE CIRCULAR AND OUTER LONGITUDINAL MUSCLE LAYERS. FEW MUSCLE FIBERS AROUND THE INTERNAL URETHRIC ORIFICE FORM AN INTERNAL URETHRAL SPHINCTER WHICH CONTROL THE OUTFLOW OF URINE FROM THE BLADDER.

ADVENTITIA:

OUTERMOST PROTECTIVE COVERING LAYER MADE UP OF DENSE IRREGULAR CONNECTIVE TISSUE.

FUNCTIONS:

  • TRANSITIONAL EPITHELIUM PREVENTS THE ENTRY OF URINE AND ITS TOXIC SUBSTANCES INTO THE URINARY BLADDER. HERE THE CELLS ALSO DECREASE IN SIZE AND LAYERS TO ACCOMMODATE LARGE QUANTITY OF URINE.
  • PROMINENT MUSCULAR COAT IS RESPONSIBLE FOR MICTURITION PROCESS BY PRODUCING POWERFUL CONTRACTIONS.
  • ADVENTITIA IS PROTECTIVE AND SUPPORTIVE IN NATURE.

CLINICAL:

  • USUALLY TRANSITIONAL EPITHELIUM¬† LINING THE URINARY BLADDER IS 4-6 CELL LAYER-THICK. IF IT INCREASES MORE THAN 6 CELL-LAYER THICK, THEN IT IS SUGGESTIVE OF CARCINOMA OF URINARY BLADDER.
HISTOLOGY OF URETER(TS)

HISTOLOGY OF URETER(TS)

IMAG0375_1IMAG0372_1

IDENTIFICATION POINTS

  • STAR SHAPED LUMEN.
  • MUCOSA LINED BY TRANSITIONAL EPITHELIUM.
  • INNER LONGITUDINAL,MIDDLE CIRCULAR AND OUTER LONGITUDINAL MUSCULAR COAT.

INTRODUCTION

– URETER IS A MUSCULAR COAT LIKE STRUCTURE WHICH CONNECTS THE KIDNEY TO URINARY BLADDER.

STRUCTURE

MUCOSA:

INNER MOST LAYER OF URETER LINED BY TRANSITIONAL EPITHELIUM WITH LAMINA PROPRIA BENEATH IT. MUCOSA IS THROWN INTO MANY FOLDS WHICH GIVES A STAR SHAPED LUMEN APPEARANCE TO THE LUMEN.

MUSCULAR LAYER:

IT IS FOUND BELOW THE LAMINA PROPRIA. CONSISTS OF INNER LONGITUDINAL,MIDDLE CIRCULAR AND OUTER LONGITUDINAL MUSCLE LAYERS.

ADVENTITIA:

OUTERMOST PROTECTIVE COVERING LAYER MADE UP OF DENSE IRREGULAR CONNECTIVE TISSUE.

FUNCTIONS:

  • TRANSITIONAL EPITHELIUM PREVENTS THE ENTRY OF URINE AND ITS TOXIC SUBSTANCES INTO THE URETER BY DIFFUSION.
  • MUSCULAR LAYER IS RESPONSIBLE FOR PERISTALSIS IN URETER WHICH PUSHES THE URINE FROM KIDNEY TO URINARY BLADDER.
  • ADVENTITIA IS PROTECTIVE AND SUPPORTIVE IN FUNCTION.

CLINICAL:

  • FORMATION OF STONES IN THE KIDNEY IS CALLED RENAL CALICULI AND IS MORE COMMON IN URETER. IT IS CHARACTERISED BY INTENSE COLIC PAIN IN THE LOIN.
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.