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Created page with '*''Senecio jacobaea'' *plant toxin ingested over a long period of time *livestock **cattle and horses are more susceptible than sheep **livestock will not normally eat the fresh …'
*''Senecio jacobaea''
*plant toxin ingested over a long period of time
*livestock
**cattle and horses are more susceptible than sheep
**livestock will not normally eat the fresh plant
**most cases arise in horses and cattle consuming ragwort in hay or silage
*'''pyrrolizidine alkaloids'''
**toxic principle converted in the body to the toxic intermediate '''pyrroles''' and their esters
**cause intitial and continued damage to hepatocytes
**have an anti-mitotic effect whilst allowing continued synthesis within the cell and its nucleus
***causes a marked increase in the size of parenchymal cells, a phenomenon termed ''''megalocytosis''''
***these very enlarged hepatocytes can be up to 20 times bigger
***the enlarged cells are closely apposed so that the sinusoids may not be evident
*it is likely that the vascular component of the attempted repair of the chronic damage by fibrosis (really a type of granulation tissue) aids the shunting from the portal triads to the central vein and thereby bypassing the hepatocytes
*other plant and fungal toxins perform in the same way
====Gross====
*slightly enlarged [[Liver - Anatomy & Physiology|liver]]
*pale in colour
*very firm to section
====Microscopically====
*necrosis
*haemorrhage
*diffuse fibrosis
[[Category:Hepatoxicity, Chronic]][[Category:Horse]][[Category:Sheep]]
*plant toxin ingested over a long period of time
*livestock
**cattle and horses are more susceptible than sheep
**livestock will not normally eat the fresh plant
**most cases arise in horses and cattle consuming ragwort in hay or silage
*'''pyrrolizidine alkaloids'''
**toxic principle converted in the body to the toxic intermediate '''pyrroles''' and their esters
**cause intitial and continued damage to hepatocytes
**have an anti-mitotic effect whilst allowing continued synthesis within the cell and its nucleus
***causes a marked increase in the size of parenchymal cells, a phenomenon termed ''''megalocytosis''''
***these very enlarged hepatocytes can be up to 20 times bigger
***the enlarged cells are closely apposed so that the sinusoids may not be evident
*it is likely that the vascular component of the attempted repair of the chronic damage by fibrosis (really a type of granulation tissue) aids the shunting from the portal triads to the central vein and thereby bypassing the hepatocytes
*other plant and fungal toxins perform in the same way
====Gross====
*slightly enlarged [[Liver - Anatomy & Physiology|liver]]
*pale in colour
*very firm to section
====Microscopically====
*necrosis
*haemorrhage
*diffuse fibrosis
[[Category:Hepatoxicity, Chronic]][[Category:Horse]][[Category:Sheep]]