Hudmon Flashcards
What are cellular responses to stress and injurious stimuli?
-homeostasis
-adaptation
-cell injury
-cell death
Homeostasis
cells maintain their intracellular environment within a narrow range of physiological parameters
Adaptation
a cells encounter physiological stress or pathological stimuli, they can undergo adaptation, achieving a new steady state and preserving viability and function by changing their size, number, and form
Cell injury
occurs when cells are stressed to the point that they are unable to adapt
cell death
one of the most crucial events in the evolution of disease in any tissue or organ (e.g. ischemia, infections, toxin, and immune responses)
Hypertrophy
an increase in the size of the cells resulting in increase in the size of the organ, there is no increase in cell number
When does hypertrophy occur?
It only occurs in cells that are incapable of dividing: striated muscles cells in both the skeletal muscle and the heart
What is the common cause of hypertrophy?
Commonly caused by increased workload
What are examples of increased workload in hypertrophy?
physiological stimuli (estrogen-induced uterus enlargement during pregnancy)
[and]
pathological conditions (hypertension, aortic valve)
how is hypertrophy charachterized?
by an increase in protein synthesis, this may be mechanical triggers (stretching) or hormonal triggers (adrenergic hormones)
Hyperplasia
increase in the number of cells (not cell size)
What are examples of physiological hormonal hyperplasia
-proliferation of the female mammary epithelium during puberty…hormones (estrogen, progesterone, and prolactin impact the number of terminal ending buds present during various stages of life)
-proliferation of connective tissue cells during wound healing
What is an examples of physiologic compensatory hyperplasia?
-regeneration of partially resected liver by the remaining hepatocytes (liver cells)
What is the typically cause of pathologic hyperplasia
-typically the result of excessive hormonal or growth factor stimulation
What can pathologic hyperplasia hyperplastic tissue lead to?
malignancy
What are example of pathological hyperplasia?
breast cancer, ovarian cancer, testicular cancer
Atrophy
shrinkage in the cell size by the loss of cell substance. No decrease in cell number. Leading to a decrease in the size of a tissue or organ
What are frequent causes of atrophy
-decreased workload
-loss of innervation (nerve growth in specific tissues or organs to regulate function)
-reduced blood supply
-inadequate nutrition
-aging (senile atrophy)
What can cause a decrease in cell size
-increased protein degradation
-reduced protein synthesis
Metaplasia
a reversible change in which one adult cell type is replaced by another adult cell type (mature somatic cell to mature somatic cell)
What is metaplasia a response to?
It is often a response to chronic irritation and inflammation that make cells better able to withstand stress
What are examples of metaplasia?
-in smokers (and vitamin A deficiency), ciliated columnar cells (ciliated columnar epithelial cels of the trachea and bronchi help clear foreign materials and mucous) are replaced by squamous epithelial cells, which are more rugged but not ciliated leading to coughing and increase in infections
-barretts esophagus
-intestinal metaplasia
Dysplasia
deranged cell growth of a specific tissue that results in cells that vary in size, number, shape, and organization (abnormal cell development and growth, mature to less mature)
What is dysplasia associated with?
chronic irritation and inflammation
When does dysplasia often occur?
often occurs in metaplastic squamous epithelium in the respiratory tract and uterine cervix
Is dysplasia adaptive?
Yes, in that it is potentially reversible after irritating cause has been removed (graded sequence after a certain point it is not reversible)
What is dysplasia a precursor of?
It is strongly implicated as a precursor (precancerous lesion) of cancer
What is an example of dysplasia?
Cervical dysplasia, which is a precursor for cervical cancer (HPV)
What causes dysplasia?
There can by many factors such as: development, mutation, or virus (HPV in cervical cancer)
Where tissue does dysplasia most often occur in?
epithelial tissue
Is metaplasia an adaptive process?
Yes, it is often triggered by environment (complicated by microorganism or inflammation)
What are the eight causes of cell injury?
-oxygen deprivation
-chemical agents
-infectious agents
-immunological reactions
-genetic defects
-physical agents
-nutritional imbalances
-aging
What are the general causes of oxygen deprivation?
hypoxia and ischemia
Hypoxia
oxygen deficiency
What are common causes of hypoxia?
-inadequate oxygenation of the blood (ex: pneumonia)
-reduction in the oxygen carrying capacity of the blood (ex: blood loss anemia or carbon monoxide poisoning in which CO forms a stable complex with hemoglobin that prevents oxygen binding)
Ischemia
loss of oxygenated blood supply to tissue
What are causes of ischemia
blockage or decrease in hearts ability to pump blood
What are examples of chemical agents?
poisons, air pollutants, CO, asbestos
What are examples of infectious agents
viruses, bacteria, fungi, parasites
what is an examples of immunological reactions
autoimmune disease
what are examples of genetic defects?
sickle cell anemia, familia hypercholesterolemia
What are examples of physical agents?
trauma, heat, cold, electric shock
Are nutritional imbalances a direct or indirect cause of injury?
typically indirect
What are examples of nutritional imbalances?
-nutritional deficiencies (caloric or vitamin)
-excess nutrition
-diabetes (can be caused by obesity, excess blood sugar levels can damage cells)
-atherosclerosis (can be caused by diet rich in fats, can result in blockage or coronary arteries)
How is aging a cause of cell injury?
As you age there is an accumulation of damage of reactive oxygen species, resulting in loss of telomerase function
What are characteristics of reversible injury?
cellular swelling or fatty change