Cell injury

What are the 4 mechanisms of cell injury? Give possible causes of each.

ATP depletion (hypoxia/anoxia, some toxins)

Permeabilisation of cell membranes (hypoxia/anoxia, ROS, infective agents)

Disrupted biochemical pathways (hypoxia/anoxia, ROS, fatty change in liver)

DNA damage (ROS, replication errors; UV rays, X-ray, gamma ray, some plant toxins, viruses)

Describe hydroptic degeneration and its cause. What cells are most prone.

Acute cell swelling

Causes cytoplasm swelling with extensive vacuolisation

Due to hypoxia

Reversible change

Hepatocytes, pancreatic acinar cells and renal tubular epithelial cells

(Ballooning degeneration is what occurs in other cell types, like keratinocytes)

What are the 3 histopathological features of acute (early and reversible) cell injury

Cell swelling

Cytoplasmic vacuolation (caused by distended endoplasmic reticulum, due to excess fluid intake by the organelle)

Hypereosinophilia

What are the three ways hepatocytes react to injury (vacuolisation)

Hydropic degeneration

Fatty change

Glycogen accumulation

What change does this liver show? Give cause

Glycogen accumulation

Gross = hepatic swelling and pallor

Cause - glucocorticoid administration

What are these liver changes? State the distributions

Hepatic lipidosis

Top = focal - tension lipidosis in a horse

Bottom = zonal - chronic passive congestion in a cow

What are the 5 possible outcomes of cell injury

Repair

Adapt

Senescence

Death/necrosis

Dysplasia → neoplasia

How is this liver reacting to injury? Describe the pathophysiology

Hydropic degeneraton

Excess fluid transferred to endoplasmic reticulum, causing vasuolisation.