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Cellular Fatty Change (view source)
Revision as of 14:14, 24 December 2014
, 14:14, 24 December 2014→Gross Appearance of Fatty Change
==Introduction==
==Introduction==
* ''NB This term does not refer to the fat stores within the body!''
* ''NB This term does not refer to the fat stores within the body!''
** Fatty substances accumulate or increase within the cytoplams of specific cells.
** Fatty substances accumulate or increase within the cytoplasm of specific cells.
** In some instances, the fat stores may be involved in the transfer of fat to these specific cells.
** In some instances, the fat stores may be involved in the transfer of fat to these specific cells.
* Cellular fatty change is an important intracellular abnormality.
* Cellular fatty change is an important intracellular abnormality.
* [[Liver - Anatomy & Physiology|Liver]]
* [[Liver - Anatomy & Physiology|Liver]]
** This is the main organ involved in fatty change.
** This is the main organ involved in fatty change.
** May be greatly increased in size.
** May be greatly increased in size with rounded edges.
** Is tan to yellowish in colour.
** Is tan to yellowish in colour.
*** Is normally reddish brown.
*** Is normally reddish brown.
*** I.e. those muscles furthest away from the blood supply.
*** I.e. those muscles furthest away from the blood supply.
** Contractile ability is reduced, and blood is therefore not pumped efficiently.
** Contractile ability is reduced, and blood is therefore not pumped efficiently.
===Histological Appearance of Fatty Change===
===Histological Appearance of Fatty Change===
* The fat either appears as globules or is contained in varying sizes of vacuoles in the cytoplasm.
* Fat appears as clear colourless vacuoles of varying sizes in the cell cytoplasm.
** In the heart, fat appears as groups of tiny vacuoles dispersed along the myofibrils.
** In the heart, fat appears as groups of tiny vacuoles dispersed along the myofibrils.
** In the [[Liver - Anatomy & Physiology|liver]] and kidney, vacuoles tend to coalesce to form larger ones.
** In the [[Liver - Anatomy & Physiology|liver]] and kidney, vacuoles tend to coalesce to form larger ones.
*** One or more large globules may fill the cytoplasm.
*** One or more large vacuoles may fill the cytoplasm.
**** The nucleus is displaced to the periphery of the cell.
**** The nucleus is displaced to the periphery of the cell.
* The nucleus remains normal.
* The nucleus remains normal.
*** [[Hydropic Degeneration#Vacuolar Degeneration|Vacuolar hydropic degeneration]]
*** [[Hydropic Degeneration#Vacuolar Degeneration|Vacuolar hydropic degeneration]]
*** Glycogen accumulation
*** Glycogen accumulation
** Stains commonly used include Sudan 111, Sudan 1V, and Oil Red O.
** Stains commonly used include Sudan III, Sudan IV, and Oil Red O.
*** Stain fat varying shades of orange to red.
*** Stain fat varying shades of orange to red.
** Sections must be prepared differently to the routine paraffin embedding (used e.g. in H&E staining).
** The strong solvents used in paraffin embedding dissolve the fat out of the cell.
*** Sections must therefore be prepared differently to the routine paraffin embedding (used e.g. in H&E staining).
*** When staining for fat, the tissue to be examined is frozen and sectioned in a cryostat before being stained.
*** When staining for fat, the tissue to be examined is frozen and sectioned in a cryostat before being stained.
**** These sections are more than twice as thick as those attained by sectioning paraffin blocks
**** These sections are more than twice as thick as those attained by sectioning paraffin blocks
***** There may be some overlap of cells on the section.
***** There may be some overlap of cells on the section.