Pathology Flashcards
ALL organ injury and clinical disease arise from what?
defects in cell structure and function (in response to something in the environment disrupting homeostasis).
What are four types of adaptations
- Hypertrophy (increase in size)
- Hyperplasia (increase in cell number)
- Atrophy (cell shrinkage leading to organ shrinkage)
- Metaplasia (cell type replaced by another better able to withstand the stress).
Example of physiological (normal) hypertrophy? example of pathological (sick condiction) hypertrophy?
Uterus during pregnancy (enlarges)
Ischemia in cardiac muscle (myocytes increase in size to remain viable).
What signals are used to initiate hypertrophy in the pathological example of ischemia in cardiac muscle?
stretch of cells (mechanical stimulus) and changes in protein synthesis alter cell.
Uterus enlarging during pregnancy is not only an example of hypertrophy but also?
hyperplasia (increase in number of cells).
Another example of physiological hyperplasia besides uterus in pregnancy?
compensatory. example if we remove a piece of tissue i.e. liver damage or surgery, cells are able to regenerate (from G0->G1). also needs a stimulus which would be groth factors by hepatocytes.
Examples of pathological hyperplasia? is this normally reversible or irreversible?
excessive hormonal/growth factor production.
if stimulus is removed this is normally reversible.
Example of physiological atrophy?
aging. comparing a young brain to an old brain we can see atrophy occuring which is normal.
Some examples of pathological atrophy?
decreased workload, loss of innervation or blood supply, nutritional deficiency or endocrine deficiency or cell size must diminish to maintain survival.
Example of pathological Metaplasia?
smoking. in lungs the epithlial layer made up of simple columnar epithelium and has cilia on apical surface. with smoking this can transform to simple stratified squamous which has a loss of cilia (can no longer expel contents) and loss of goblet cells (only located in columnar).
Is Metaplsia often reversible or irreversible?
reversible, if stimulus is removed.
Another example of pathological metaplasia which has some positive effects?
chronic gastric reflex. transforms from squamous to columnar (esophagus to intestinal tissue) which becomes a more protective layer due to the goblet cells.
What are the two types of cell death?
apoptosis and necrosis.
Differences between apoptosis and necrosis?
apoptosis: membrane does NOT fragment, NO inflammatory response, membrane in tact with various bubbles released.
Necrosis: cell membrane fragments (starts by blebbing), releases contents into extracellular space and causes inflammatory response.
What are seven common causes of cell injury?
- Hypoxia (Ischemia, pneumonia, anemia or CO poisoning)
- Chemicals (air pollutants, ethanol. issues in membrane perm, osmotic homeo and enzyme damage)
- Infections (viruses, bacteria, parasites)
- Genetic (i.e. sickle cell, enzyme abnormalties).
- Nutritional imbalance
- Physical Agents (i.e. trauma, temperature, shock, pressure)
- Aging (replication and repair abilities damaged).
Is mitochondrial dysfunction reversible?
NO
What is a factor that determines point of no return?
disturbances in membrane function.
What are the three histological patterns in changes of the nucleus?
breakdown DNA and chromatin.
- Basophilia fades (Karyolysis)- increase in eosinophilia.
- Pyknosis: shrinkage and increased basophilia (DNA solid mass)
- Karyorrhexis: fragmentation of nucleus (nucleus disappears in 2-3 days).