Chronic cell injury and adaptation Flashcards
how cells respond to injury or stress?
adaptation, death or reversible injury
sublethal injury over time leads to?
hypertrophy, hyperplasia, atrophy, other ways of degeneration
what do cells do in case of sublethal injury?
autophagocytosis
autophagocytosis
removal of damaged organelles by phagocytosis
how is autophagocytosis seen microscopically?
as autophagic vacuoles which appear as eosinophilic inclusions
what happens to the autophagic vacuoles?
some are evicted, others remain as residual bodies
where are autophagic vacuoles commen as residual bodies?
liver and kidney
adaptive changes of the cell
hyperplasia
hypertrophy
metaplasia
atrophy
metaplasia
change of cell type
hypertrophy
increase in cell size due to increase of structural components of the cell
effects of hypertrophy
increased functional capacity
hypertrophy can be?
pathological or physiological
Physiological hypertrophy is caused by?
Hormonal stimulation
- lactation
- gestation
Greater functional demand
- increased muscle workload
- growth of the right side of cardiac muscle due to stenosis
What is the difference between the hypertrophy of both sides of heart vs one side of the heart?
Both sides: systemic
One side: local
Pathologic hypertrophy
-compensation mechanism for a lost/impaired organ
or a part of organ
if two paired organs are of different size which one is normal?
usually none, since other has often atrophy and the other hypertrophy as compensation
Hyperplasia
increase in the nr of cells due to increased mitotic division
what is the relationship between hyperplasia and hypertrophy?
they often go hand in hand although they are two different processes. macroscopically it is impossible whether the organ has enlargened due to hyperplasia or hypertrophy
which cells are easily affected by hyperplasia?
epidermis, intestinal epithelium, bone marrow
which cells aren’t easily affected by hyperplasia?
neurons
cardiac and skeletal myocytes
physiologic hyperplasia
hormonal or compensatory
pathologic hyperplasia
chronic irritation or hormonal stimulation (for
example, goiter)
nodular hyperplasia
normal in older animals, especially in spleen
can metaplasia change the cell to any type of cell?
no, only to a cell of the same germline
typical metaplasia
the specialized epithelium is replaced by less specialised epithelium
why metaplasia happens?
usually an adaptive change to adverse environmental conditions
is metaplasia reversible or irreversible?
reversible if the cause is removed, however it can lead to neoplastic changes
atrophy
decrease in cell/tissue/organ amount or size after the normal growth
atrophy types
physiological (for example, post-partum uterus) or pathological
causes of atrophy
decreased use (muscle)
denervation (nerve damage causes muscle atrophy)
decreased blood supply (liver)
lack of nutrient supply (fat and weight loss)
loss of endocrine stimulation (mammary gland)
senility
pressure (mass, hydrocephalus, compression)
examples of decreased blood supply atrophy causes
shunt (blood goes to wrong place)
common causes of pressure atrophy?
masses and lesions cause atrophy in adjacent tissues
lipomatous pseudohypertrophy
form of atrophy where muscle fibers die but the tissue looks enlargened due to fat accumulation
serous atrophy
typical finding in cachexy
loss of fat which is replaced by gelatinous tissue
when fat is lost from heart?
in very severe cachexy
serous atrophy
