General Pathology 2 PDF

G Path 2 Friday, 4 March 2022 2:24 PM Most cell damage situations are MEDIATED by lack of oxygen Physical trauma, inflammation also causes damage, could get infected Trauma by blood loss Tourniquets Resp diseases Brain-nor resp-no oxy Anaemia Sickle cell Malaria eats Hb Parasites that eat bloo...

G Path 2 Friday, 4 March 2022 2:24 PM Most cell damage situations are MEDIATED by lack of oxygen Physical trauma, inflammation also causes damage, could get infected Trauma by blood loss Tourniquets Resp diseases Brain-nor resp-no oxy Anaemia Sickle cell Malaria eats Hb Parasites that eat blood Blood clots Heart issues Ischemia = blood not reaching the tissues or an organ Hypoxia = lack of oxygen in the blood Unstable mollecules with unpaired electrons in the outer shel, so they are high energy and go around and smash out electrons from other mollecules making MORE free radicals and damaging cellular mollecules of all kinds in the process There is a range of things that can happen to the nuclei in necrosis - Karyolysis = dissolved nucleus - Pyknosis = small dark and shrunken - Karyorrhexis = dark fragments These changes tell us that necrosis has occurred The severity or scale of the diseased tissue is the only difference between these two lung sets, this needs to be described Classifying necrosis can tell us a bit about the cause Saw leasions in the lungs with a specific kind of necrosis so they decised to wear masks because this type of necrosis indicated TB! But remember death is a dynamic process, so necrosis can stick around in the tissues and change from one kind to another kind Peracute = really recent/fast Coagulate = clumping This is when a tissue is dead but the architecture is still normal, you can still tell what type of tissue it is. So the shape is not changed, but the cellular architecture is lost due to necrosis Coagulative necrosis due to loss of blood supply to this wedge of kidney. It still looks like kidney even histologically but the CELLS are different in colour and fragmented nucleus, cant see membranes etc Looks like cheeses You loose the cellular structre like all necrosis but you also loose the architectural detail aswell This is characteristic of some bacteria particularly TB This is a lymph node with caseous necrosis due to pseudo TB  Loose cell detail and architectural detail This is usually seen in the CNS So there is pus (neutrophils and tissue fluid and bacteria) as well as the liquefied necrotic tissues This happens due to bacteria in the tissue attract neutrophils, both give off enzymes and this causes necrosis Pus is septic, NOT sterile as it is caused by bacteria  Formation of soap by the addition of salts to fatty acids So adipose tissue dies, cells pop, and ions are released which combine with the fatty acids and become opaque and grainy/gritty and is no longer oily feeling but dry and crunchy this can retain the tissue architecture as well Steatitis is the inflammation of fat, commonly yellow fat, causing saponification and fat necrosis. Can tell by presence or absence of neutrophils on a smear of the contents (caseous does not have any/many)  Something needs to happen to get rid of the necrotic tissue This mainly occurs in CNS The fluidy stuff and dead material gets absorbed into lumphatics More particulate matter removed by neautriphils Wall off the tissue, confine it and make it harmless. The dead tissue in the middle cant release enzymes or cytokines The process of abcessation does not work within internal organs because they are unable to burst and release the goop, so the animal will die from systemic effects This is when the dead tissue is on a surface (skin, organ, lumen) So they get excreted and the lesion that is left behind is called either an erosion or an ulceration. This is an ulcer In this case like a bed sore, from being chained up and laying on concrete and being underfed. gangrene erosion Tissue dies because of lack of blood supply Gangrene is ischemic necrosis of the extremities This can cause seccondary bacterial infection due to lack of blood supply, no WBC no way to fight infection Deprived of blood supply and undergoes coagulative necrosis Eg: frostbite If untreated you will either get sloughing or death. DRY MOIST This is a human hand