Cell Adaptation Flashcards
What are 3 characteristics of cell adaption?
1) Cells preserve viability and function
2) It is a reversible change
3) Principle responses to adaptation are: atrophy, hypertrophy, hyperplasia, and dysplasia
What could cause disruption of cell homeostasis?
Could be caused by stresses and pathological stimuli
Clicker question: Etiology refers to?
Cause of a disease
Describe atrophy.
It is the decrease in size and/or number of the cells and their metabolic activity after normal growth has been reached.
Described as decrease in protein synthesis and increase of protein degradation in cells.
Cells are NOT dead.
Causes may include reduction of their nutrient source, decreased blood supply or O2, decreased workload, denervation, loss of endocrine stimulation, or aging
What are some examples of atrophy?
Muscle disuse in a limb that’s in a cast
Sedentary
Atrophy of adrenal cortex by reduction of ACTH stimulation (steroid therapy)
Atrophy in tissues adjacent to a tumor due to pressure and compromised blood flow
Describe hypertrophy
It is the increase in size of cells and their functions
Synthesis of more organelles and structural proteins > bigger cells
What type of cells is hypertrophy more common in?
Cells with little replication, stable, or permanent cells.
Ex. Cardiomyocytes and neurons
What is an example of pathologic hypertrophy?
Cardiac hypertrophy from hypertension or aortic valve dz
Name the dog and cat breeds that are susceptible to cardiac hypertrophy.
Cat: Maine Coon
Dog: Boxers and Bernese Mountain Dogs
What is hyperplasia?
It is the increase in the number of cells of an organ.
Cells ARE capable of replication.
List 2 reasons for physiologic hyperplasia and give an example for each
Hormonal: breasts during pregnancy
Compensatory: cells of the liver after a hepatectomy
What could be the cause(s) of pathologic hyperplasia?
Most commonly caused by: excessive hormonal or growth factor stimulation
Ex.: epidermal thickening due to repeated irritation (would get more than the normal 3 layers of cells; respiratory mucosa in viral infections
Describe metaplasia (5 characteristics).
Change in the phenotype of a differentiated cell.
Response to chronic irritation > helps cell withstand stress.
May result in decrease functions or increase propensity for malignant transformation (neoplasia).
Reversible if cause is removed.
Most often in epithelial cells.
Name 3 metaplasia examples.
Chronic irritation to lungs (such as smoking).
Vit-A deficiency.
Estrogen toxicity- mammary tumors
Describe dysplasia.
Refers to abnormal development (mostly of epithelial tissue).
Term mostly used in neoplastic processes.
Near synonym: “carcinoma in situ”
Anisocytosis (size).
