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→Glycogen Infiltration
* Glycogen is normally present in substantial amounts in the liver and muscle.
* Glycogen is normally present in substantial amounts in the liver and muscle.
** Is a readily utilisable source of energy.
** Is a readily utilisable source of energy.
* Moderate glycogen infiltration in the liver:
** '''Grossly'' - doesn't have much effect.
** '''Histologically''' - shows up as foamy cytoplasmic vacuoles, similar to that of fat.
* Some conditions may result in an increase in glycogen deposits.
* Some conditions may result in an increase in glycogen deposits.
** '''Diabetes mellitus''
** '''Diabetes mellitus'''
*** Gives an increase in hepatic glycogen stores.
*** Gives an increase in hepatic glycogen stores.
*** May be overshadowed by the increased fat in the hepatocytes, and therefore difficult to see.
*** May be overshadowed by the increased fat in the hepatocytes, and therefore difficult to see.
**** Renal tubular deposits are more easily observed.
**** Renal tubular deposits are more easily observed.
** '''Excessive glucocorticoids'''
** '''Excessive glucocorticoids'''
** Excessive glucocoritcoids could be due to:
*** Could be due to:
*** Hyperadrenocortism
**** Hyperadrenocortism
*** Animals being maintained on glucocorticoid therapy over a long period of time.
**** Animals being maintained on glucocorticoid therapy over a long period of time.
**** More dramatic effects.
***** Has more dramatic effect.
* Liver appears larger and paler following glycogen infiltration.
*** Huge amounts of glycogen infiltration.
** Moderate amounts of glycogen do give much alteration in the gross appearance of the organ.
**** Liver appears larger and paler.
** Histologically, moderate glycogen in the hepatocyte shows up as foamy cytoplasmic vacuoles, similar to that of fat.
**** Vacuoles may be so extensive that the rest of the cytoplasm appear as pink strands passing from the nucleus to the plasma membrane.
** In prolonged glucocorticoid therapy, the amount of glycogen in the vacuoles may be so extensive as to make the rest of the cytoplasm appear as pink strands passing from the nucleus to the plasma membrane.
***** A "feathery appearance" or "web-like effect".
*** This is sometimes called a feathery appearance or web-like effect.
** '''Glycogen storage diseases'''
* A further example of glycogen infiltration occurs in the glycogen storage diseases.
*** Due to an inherited deficiency of an enzyme required for the breakdown of glycogen to glucose.
** These are due to an inherited deficiency of an enzyme required for the breakdown of glycogen to glucose in the cells of the body.
**** Cells continuously accumulate glycogen.
** These cells continuously accumulate glycogen.
*** Seen in all tissues of the body but exerts its major effect in the CNS.
** This is seen in all tissues of the body but exerts its major effect in the CNS, and will be dealt with in that system.
* Selective staining must be employed to distinguish glycogen vacuoles from fatty vacuoles in the liver.
** Alcohol fixation is preferred. T
** Best's Carmine is the commonly used stain.
*** Stains the intracellular glycogen red.
preferred. The stain commonly employed is called Best's Carmine staining the intracellular
* Seen particularly in:
** The kidney tubular epithelia in Diabetes mellitus.
===Cellular Inclusions===
===Cellular Inclusions===