Cell injury

• metaplasia: change from one differentiated form to another

  • bronchial epithelium can undergo squamous metaplasia after exposure to polycyclic hydrocarbons

  • esophageal epithelium can undergo glandular metaplasia (Barrett’s esophagus), a consequence of acid reflux

  • cervical epithelium can undergo squamous metaplasia; this is due to papilloma viruses

  • the third way to get squamous cancer is via radiation from the sun

  • so squamous cancers don’t tell you how the cells got there

• dysplasia: change to an abnormal differentiated form

• anaplasia: loss of differentiation. neoplasia: new growth (usually sloppily used to mean “cancer”)

• aplasia: failure to develop normal tissue

  • often, hypoplasia is incorrectly termed aplasia. aplastic anemia is more precisely hypoplastic anemia, not completely aplastic anemia

  • lots of cancer drugs that we give people lead to bone marrow hypoplasia. many people who undergo chemotherapy die of bleeding, infection, or anemia

  • lymphoid tissue can undergo aplasia (SCID, drugs)

  • a hypoplastic left ventricle is one of the most common congenital abnormalities that you will see in the neonatal nursery

• necrosis: death of tissue due to a disease process

  • distinguish this from apoptosis, which is not necessarily due to a disease process

  • infarction: death due to lack of blood supply, as in myocardial infarction, stroke (cerebral infarction), renal infarction, bone infarction

• cellular inclusions

  • these indicate that a cell has been damaged somehow

  • fatty change is most commonly seen in this society as a consequence of alcoholic liver disease. increased production of lipids and decreased secretion of lipids leads to this fatty change

  • metabolic products: hemochromatosis or hemosiderosis leads to excess uptake of iron by cells. lipofuscin is a general wear-and-tear pigment seen with age

Category: Medical Subject Notes , Pathology Notes