Cellular injury Flashcards
Autopsy
Used to accurately determine the cause of death
Performed for legal purposes, medical purposes, audits and education
Can only be carried out by a government-appointed pathologist
Why does cell injury occur?
Cells become injured when they are unable to cope with a change in environment or a challenging stimulus
Causes of cell injury
- Oxygen deprivation
- Physical agents
- Chemical agents
- Infectious agents
- Immunologic reactions
- Nutritional imbalances
- Genetic defects
Free radicals
Chemical species with a single unpaired electron in their outer shell, very reactive
Generated due to radiation, redox reactions, nitric oxide and transition metals
Free radical damage
ROS damage cells due to
- Lipid peroxidation of membranes
- Oxidative modification of proteins
- DNA damage
Cell damage - functional changes
- Decreased production of ATP
- Loss of membrane integrity
- Defects in protein synthesis
- Cytoskeletal damage
- DNA damage
Cell damage - morphological changes
- Cellular swelling
- Blebbing
- Mitochondrial swelling
- Dilation of endoplasmic reticulum
- Nuclear alterations
Necrosis
Necrosis is a mechanism of uncontrolled cell death
It causes cell contents to spill into the extracellular fluid, causing nearby cells to also die
Coagulative necrosis
The most common type of necrosis
Typical of hypoxic cell death (except for the cells of the CNS)
Cell structure is maintained but organelles and the cytoplasm coagulate, staining red with eosin
Liquefactive necrosis
Typical of cell death relating to a bacterial infection OR hypoxic cell death of the CNS
Cells are completely digested into a liquid viscous mass (pus) and attract a large number of leukocytes
Caseous necrosis
Typical of cell death relating to a tuberculosis infection
Tissue architecture is completely destroyed, leaving behind a cheesy white mass
Fat necrosis
Typical of death of fat tissue
Mainly seen in acute pancreatitis, whereby the pancreas releases large amounts of lipases
Leads to chalky deposits of calcium in and around the tissue
