Irreversible Cell Injury and Cell Death Flashcards
The cellular response to injury depends on?
- The type of cell
- The severity
- The duration
Susceptibility of cells to Hypoxia
‣ High
• Neurons: (3-5 min)
‣ Intermediate
• Myocardium, hepatocytes, renal epithelium (30 min - 2 hr)
‣ Low
• Fibroblasts, epidermis, skeletal muscle (many hrs)
What happens in the case of severe and persistent injury?
Severe and persistent injury —> point of no return.
- Inability to reverse mitochondrial dysfunction
- Severe dysfunction of cell membranes (Lysosomal membranes → Lysosomal enzymes)
- Increased intracellular calcium levels
What can necrosis lead to?
• Necrosis —> Pathological (point of no return) —> Oncotic necrosis (oncosis [derived from onkos, meaning swelling).
What does apoptosis lead to?
Physiologic cell death/Programmed cell death.
Name and explain three situations in which the body has reached the point of no return?
◦ Ultrastructural
‣ Swelling
‣ Rupture of plasma membrane and organelles (leakage of contents)
‣ Rupture of nucleus
‣ Mitochondria are swollen and develop amorphous densities
◦ Microscopic
‣ Hypereosinophilic cytoplasm (due to denatured proteins and loss of ribosomes)
‣ Nuclear changes:
‣ Pyknosis (nuclear condensation with shrinkage and intense basophilia)
‣ Karyorrhexis (nuclear fragmentation)
‣ Karyolysis (nuclear dissolution or loss)
◦ Gross (macroscopic)
‣ In general:
• Swelling and pallor (soon after cell death)
• Loss of structural detail and demarcation from adjacent viable tissue
• Discolored (usually white)
• Soft
‣ It varies a lot; it depends of: tissue involved, the nature of the injurious agent, and the time elapsed after cell death.
‣ Necrosis has been classified as coagulative, caseous, liquefactive or lytic, and gangrenous
Microscopic images here
What are the types of oncotic necrosis?
- Coagulative necrosis
- Caseous necrosis
- Liquefactive necrosis
- Gangrenous necrosis
- Fat necrosis
- Necrosis of epithelium
- Sequelae to oncotic necrosis
- Cell death by apoptosis
What is Coagulative necrosis typically caused by?
Hypoxia, ischemia, or toxic injury
Coagulative necrosis image + description
Caseous necrosis image here + description
Liquefactive necrosis image + description
Gangrenous necrosis image (wet) + description
Gangrenous necrosis image + description
What are the three types of fat necrosis?
• Enzymatic:
◦ Occurs secondary to leakage of pancreatic enzymes (lipases) in cases of pancreatitis
• Traumatic:
◦ Blunt trauma or chronic pressure against bony prominences (subcutaneous adipose tissue in recumbent animals)
• Idiopathic (unknown cause): ◦ Necrosis of abdominal fat in overconditioned cattle
