NR283 Pathophysiology Study Guide for Exam 1
Chapter 1: Intro to Pathology
1 & 2. Describe the cellular adaptations made in each of the following processes and their causative
factors: atrophy, hypertrophy, hyperplasia, dysplasia, and metaplasia
Atrophy- a decrease in the size of cells, resulting in a reduced tissue mass. Common causes
include reduced use of the tissue, insufficient nutrition, decreased neurologic or hormonal
stimulation, and aging
Hypertrophy- an increase in the size of individual cells, resulting in an enlarged tissue mass. This
increase may be caused by additional work by the tissue, as demonstrated by an enlarged heart
muscle resulting from increased demands
Hyperplasia- an increased number of cells resulting in an enlarged tissue mass. Hyperplasia may
be a compensatory mechanism to meet increased demands, or pathologic when there is a hormonal
imbalance, or it may mean there is an increased risk of cancer
Dysplasia- tissue in which the cells vary in size and shape, large nuclei are frequently present, and
the rate of mitosis is increased. May result from chronic irritation infection, or may be a
precancerous change. Detection of dysplasia is the basis of routine screening tests for atypical
cells such as the Pap smear
Metaplasia- when one mature cell type is replaced by a different mature cell type. May result
from a deficit of vitamin A. Metaplasia is sometimes an adaptive mechanism that provides a more
resistant tissue (i.e. when stratified squamous epithelium replaces ciliated columnar epithelium in
the respiratory tracts of cigarette smokers. The new cells make a stronger barrier but they decrease
defenses for the lungs because they lack cilia)
3. Identify the most common cause of cellular injury.
The most common cause of cellular injury is ischemia (decreased supply of oxygenated blood to a
tissue or organ, due to circulatory obstruction), which results in hypoxia (reduced oxygen in
tissue) and reduced cellular metabolism
Other causes of cell injury:
● Physical agents - excessive health or cold or radiation exposure
● Mechanical damage such as pressure or tearing of tissue
● Chemical toxins
● Microorganisms such as bacteria, viruses, and parasites
● Abnormal metabolites accumulation in cells
● Nutritional deficits
● Imbalance of fluids or electrolytes