Author, Donkey, Bureaucrats, Administrators
53,803
edits
Changes
no edit summary
==Introduction==
==Introduction==
* '''Necrosis''' means the death of cells within the living body.
* '''Necrosis''' means the death of cells within the living body.
===Loss of Blood Supply===
===Loss of Blood Supply===
* Necrosis due to interuption of blood supply to a portion of tissue is known as '''ischaemic necrosis''', or [[Ischaemia and Infarction - Pathology#Infarction|'''infarction''']].
* Necrosis due to interuption of blood supply to a portion of tissue is known as '''ischaemic necrosis''', or [[Infarction|'''infarction''']].
* The effects of [[Ischaemia and Infarction - Pathology#Ischaemia|ischaemia]] on a tissue vary according to:
* The effects of [[Ischaemia|ischaemia]] on a tissue vary according to:
** The tissue affected.
** The tissue affected.
*** Some tissues are more susceptible than others.
*** Some tissues are more susceptible than others.
* Tissue [[Ischaemia and Infarction - Pathology#Ischaemia|ischamia]] can be brought about in three ways:
* Tissue [[Ischaemia|ischamia]] can be brought about in three ways:
** Compression of the blood vessel.
** Compression of the blood vessel.
** Narrowing of the lumen.
** Narrowing of the lumen.
====Blocking of the Lumen====
====Blocking of the Lumen====
* Important causes are [[Thrombosis - Pathology#Introduction|thrombi]] and [[Thrombosis - Pathology#Embolism|emboli]].
* Important causes are [[Thrombosis#Introduction|thrombi]] and [[Embolism|emboli]].
* Renal vessels are commonly affected.
* Renal vessels are commonly affected.
** Also contains the remnants of the necrotic tissue cells.
** Also contains the remnants of the necrotic tissue cells.
* Although in favourable cases the [[Neutrophils|neutrophils]] may eventually kill the organisms, in most cases the organisms persist, producing more pus.
* Although in favourable cases the [[Neutrophils|neutrophils]] may eventually kill the organisms, in most cases the organisms persist, producing more pus.
** Produces an expanding sphere of pus known as an [[Acute Inflammation - Pathology#Purulent|'''abscess''']].
** Produces an expanding sphere of pus known as an [[Purulent Inflammation|'''abscess''']].
*** If the abscess is near to the skin and pressure becomes sufficient after build up, it will burst.
*** If the abscess is near to the skin and pressure becomes sufficient after build up, it will burst.
**** Pus is discharged, hopefully along with the organisms responsible.
**** Pus is discharged, hopefully along with the organisms responsible.
* The zone of inflammation between the dead putrefying tissue and living tissue is indistinct.
* The zone of inflammation between the dead putrefying tissue and living tissue is indistinct.
=====Gas Gangrene=====
=====[[Gas Gangrene]]=====
====Dry Gangrene====
====Dry Gangrene====
*** Commonly seen following a septicaemic condition when an embolus blocks the blood supply.
*** Commonly seen following a septicaemic condition when an embolus blocks the blood supply.
**** When seen in calves, the possibility of [[Salmonellosis|salmonellosis]] must be kept in mind.
**** When seen in calves, the possibility of [[Salmonellosis|salmonellosis]] must be kept in mind.
*** Other causes are frostbite and [[Skin Environmental - Pathology#Ergot poisoning|ergot poisoning]].
*** Other causes are frostbite and [[Ergot Poisoning|ergot poisoning]].
==Calcification==
==Calcification==
** The cell breaks up into fragments that are engulfed by neighbouring cells or local macrophages.
** The cell breaks up into fragments that are engulfed by neighbouring cells or local macrophages.
*** Their remnants can be seen in the neighbouring cells’ cytoplasm.
*** Their remnants can be seen in the neighbouring cells’ cytoplasm.
[[Category:General Pathology]]