Cellular Injury Flashcards
hypertrophy
increase in size of an organ or tissue due to an increase in the size of cells.
hypertrophy is characterized by
an increase in protein synthesis and size and number of organelles.
two examples of cellular adaptation to increased workload
increase in skeletal muscle mass associated with exercise.
enlargement of the left ventricle of heart in hypertensive heart disease.
hyperplasia
increase in the size of an organ or tissue caused by an increase in the NUMBER of cells.
example of hyperplasia
glandular proliferation in the breast during pregnancy.
some tissue undergo hyperplasia and hypertrophy
during pregnancy, uterine enlargement is caused by both hypertrophy and hyperplasia of the smooth muscle cells in the uterus.
After an abnormality ceases (increased functional/energy/work demand, tissue injury), what happens is
reduced cell size and cell number.
Tissues that lack a stem cell reservoir cannot undergo
hyperplasia. They can ONLY undergo hypertrophy (skeletal muscle, brain and spinal cord).
aplasia
failure of cell production
during fetal development, aplasia results in
agenesis, absence of an organ due to failure of production.
later in life, aplasia can be caused by
permanent loss of precursor stem cells in proliferative tissues, such as the bone marrow.
atrophy
decrease in the size of an organ or tissue resulting from a decrease in the mass of pre-existing cells.
atrophy results most often from
disuse, nutritional or oxygen deprivation, diminished endocrine stimulation, aging and denervation.
during atrophy, stem cell reserve is
intact
atrophy is often marked by the presence of
autophagic granules, vacuoles contining debris from degraded organelles.
metaplasia
the replacement of one differentiated tissue by another.
metaplasia examples
squamous metaplasia
osseous metaplasia
myeloid metaplasia
squamous metaplasia
the replacement of columnar epithelium at the squamocolumnar junction of the cervix by squamous epithelium.
places where squamous metaplasia occurs
cervix
respiratory epithelium
endometrium
pancreatic ducts.
true or false: squamous metaplasia is reversible
true
osseous metaplasia
the formation of new bone at sites of tissue injury. Cartilaginous metaplasia may also occur.
myeloid metaplasia
proliferation of hematopoietic tissue in sites other than the bone marrow, such as the liver or spleen.
reversible cell injury
pathologic changes reversible with removal of stimulus.
in reversible cell injury, if stimulus is persistent but not too intense, cells may
undergo adaptation to survive.