Changes

===Glycogen Infiltration===

===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.

** Hepatic glycogen stores are increased in diabetes mellitus

*** May be overshadowed by the fat.  

** '''Diabetes mellitus''

** Renal tubular deposits are more easily observed.

*** Gives an increase in hepatic glycogen stores.

* Increase glycogen deposits are also seen in animals under the influence of excessive glucocorticoids.

*** May be overshadowed by the increased fat in the hepatocytes, and therefore difficult to see.  

** Could be due to hyperadrenocortism (excess secretion of glucocorticoids), but is more dramatic when animals are maintained on glucocorticoid therapy over a long period of time>

**** Renal tubular deposits are more easily observed.

in which the liver appears larger and paler. Moderate amounts of glycogen do not produce appreciable alteration in the gross appearance of the organ. Histologically, moderate glycogen in the hepatocyte shows up as foamy cytoplasmic vacuoles, similar to that of fat. 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. This is sometimes called a feathery appearance or web-like effect. A further example of glycogen infiltration occurs in the glycogen storage diseases. These are due to an inherited deficiency of an enzyme required for the breakdown of glycogen to glucose in the cells of the body. These cells continuously accumulate glycogen. 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.

** '''Excessive glucocorticoids'''

To distinguish glycogen vacuoles from fatty vacuoles in the liver, it is necessary to stain

** Excessive glucocoritcoids could be due to:

*** Animals being maintained on glucocorticoid therapy over a long period of time.

* Liver appears larger and paler following glycogen infiltration.  

** Moderate amounts of glycogen do give much alteration in the gross appearance of the organ.  

** Histologically, moderate glycogen in the hepatocyte shows up as foamy cytoplasmic vacuoles, similar to that of fat.

** 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.  

*** This is sometimes called a feathery appearance or web-like effect.  

* A further example of glycogen infiltration occurs in the glycogen storage diseases.  

** These are due to an inherited deficiency of an enzyme required for the breakdown of glycogen to glucose in the cells of the body.  

** These cells continuously accumulate glycogen.

** 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.

o distinguish glycogen vacuoles from fatty vacuoles in the liver, it is necessary to stain

selectively. I have already mentioned the fat stains and the special procedure for preparation

selectively. I have already mentioned the fat stains and the special procedure for preparation

of the tissue. Glycogen can be stained using routine preparation but some is lost due to it

of the tissue. Glycogen can be stained using routine preparation but some is lost due to it