Irreversible Cell Injury and Cell death Flashcards
What determines the cellular response of injury?
(1) the type of cell,
(2) the severity
(3) the duration
What cell is the most susceptible to hypoxia?
Neurons (3-5 minutes)
What are the cells that are susceptible to hypoxia within 30 minutes to 2 hours?
Myocardium, hepatocytes, renal epithelium
What are the cells that are susceptible to hypoxia many hours later?
Fibroblasts, epidermis, skeletal muscle
What is Oncotic necrosis?
Pathologic.
Swelling ( and damage from swelling) due to increased sodium and increased H2O in cell.
What is Apoptosis?
Physiologic cell (point of no return) death/Programmed cell death Considered Physiologic and Pathologic
What are the 3 points of no return in cell injury?
- Increased mitochondrial damage.
- Increased Cell Membrane Permeability
- Increased Calcium
What are the ultrastructural indications of oncotic necrosis?
- Swelling
- Rupture of plasma membrane and organelles ( leakage of contents which attracts inflammatory cells)
- rupture of nucleus
- Swollen Mitochondria and develop amorphous densities
What are the microscopic indications of oncotic necrosis?
- Hypereosinophilic cytoplasm ( due to denatured protiens and loss of ribosomes)
- Nuclear Changes:
Pyknosis (nuclear condensation with shrinkage and intense basophilia) - Karyorrhexis (nuclear fragmentation)
- Karyolysis ( nuclear dissolution or loss)
What nuclear change is occuring in this image?
- Pyknosis (nuclear condensation with shrinkage and intense basophilia)
What nuclear change is occuring in this image?
Karyorrhexis (nuclear fragmentation)
What nuclear change is occuring in this image?
Karyolysis (nuclear dissolution or loss)
What is occuring at letters A-C in this histological image?
A.) Pyknosis
B.) Karyorrhexis
C.) Karyolysis
What is occuring to the cells in this image?
Necrotic neurons with hypereosinophilic cytoplasm and pyknotic nuclei
What is occuring in this image?
Nuclear karyorrhexis
What can be seen in gross observation of cells with oncotic necrosis?
- Swelling and pallor (soon after death)
- Loss of structural detail and demarcation from adjacent viable tissue.
- Discolored (usually white)
- Soft
Varies alot and dependent on tissues involved, time between death and necropsy, and nature of injurious agent.
What are the classifications of necrosis?
Coagulative
Caseous
Liquefactive
What is important to remember about types of necrosis/
The morphologic appearance of necrotic cells and tissues changes
with time.
Coagulative necrosis → Liquefactive necrosis
What are the causes of coagulative necrosis?
hypoxia, ischemia, or toxic injury
What are observational indications that would infer the section is of coagulative necrosis?
- General tissue architecture preserved
- Cell outlines still recognizable
- Pale tan to pale gray (it can be red, hemorrhagic: hemorrhagic infarct and venous infarct)
- Often sharply demarcated from the adjacent viable tissue
• Solid (without apparent crumbling, sloughing, liquefaction, or other obvious loss of
structure)
What is an infarct? What kind of necrosis can this be seen in?
Infarct: a focal area of coagulative necrosis resulting from failure of blood supply (ischemia)
What is a hemmorrhagic infarct?
Blood enters the infarcted tissue because blood flow restored in the obstructed
vessel or arrived from collateral circulation
What is an ischemic infarct?
After a few days macrophages remove the blood from acute hemorrhagic infarct
What is a venous infarct?
infarct when vein is occluded due to some sort of compression
i.e strangulating lipoma, small intestinal volvulus
What is a strangulating lipoma? What animal is it more common in?
It is a lipoma that causes a section of intestine to loose blood supply. This occurs in horses.
What is occuring in this image? What would be the characteristic that indicates what is going on?
Toxic injury. The pale color to the tissue.
What is occuring in this image?
Toxic Injury
- There is prominent lobular pattern
What is ocurring in this histological section? What does it indicate?
- Eosinophillic staining + Nuclei loss or Pyknosis.
There are preservation of cell outlines though.
Coagulative Necrosis.