Neuro

Question 1

12-24 hours after irreversible ischemic injury

Answer 1

• Red neurons
  characterized by intense eosinophilic staining of the cytoplasm
• In addition, Nissl substance disappears, and the nuclei become pyknotic (eg, shrunken and deeply basophilic) and undergo fragmentation (karyorrhexis).

Question 2

24-72 hours

Answer 2

tissue damage promotes neutrophil infiltration

Question 3

3-7 days

Answer 3

followed by macrophage/microglial recruitment a few days afterward.

Question 4

3-6 hours

Answer 4

typically little change in the microscopic or macroscopic appearance of brain tissu

Question 5

1-2 weeks

Answer 5

• robust phagocytosis of neuron and myelin breakdown products by activated macrophages/microglia.
• astrocytes start proliferating with the development of a network of cytoplasmic extensions (reactive gliosis), and new vessels are formed in the periphery of the necrotic area.

Question 6

Several months to years after brain infarction,

Answer 6

necrotic area appears as a cystic cavity surrounded by a wall of dense fibers formed by astrocytic processes (glial scar).