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NUR 300, Cellular Adaptation, Chapter 5

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What is Atrophy?
A decrease in cell size.
Particularaly in muscle tissue, related to work load.
Causes of Atrophy...
1) Disuse
2) Denervation
3) Loss of endocrine stimulation
4) Inadequate nutrition
5) Ischemia or decreased blood flow.
What is Hypertrophy?
An increase in cell size.
With is comes an increase in the amount of functioning tissue mass. (Examples: thickening of urinary bladder, myocardio hypertrophy)
What happens on the cellular level of atrophy?
Reduce Oxygen consumption.
Organells decrease in size and number.
Causes of Hypertrophy...
Increased workload or demand.
What is Hyponatremia?
Water follows solute into cells and they SWELL.
Directions of ion Pumps
K --> in
Na --> out
What is first messenger?
Extracellular signals, including neurotransmitters, protein hormones and growth factors, steroids.
What is a second messenger?
Intracellular mechanisms for signaling. Many are proteins.
Change is proportional to _______ .
Stimulus
What is Cellular Adaptation?
A Change in size, number, and/or type of cell.
A response from the cell through receptors that detect a change through envrionmental stimulus and gene changes.
Can be normal or abnormal.
What is Hyperplasia?
Increased number of cells.
From Increased demand. It is controlled, however, and ceases when stimulus ends.
Where does hyperplasia occur?
In tissues with cells that are capable of mitotic division, such as the epidermis, intestinal epithelium, and glandular tissue. (Ex: regeneration of liver after partial hepatectomy)
What causes Hyperplasia?
An activation of genes that control cell proliferation, replication, and growth.
What is Metaplasia?
A reversible change in which one adult cell type is replaced by another adult cell type.
What causes Metaplasia?
The response to chronic irritation and inflammation and allows for substitution of cells that are better able to survive under circumstances in which a more fragile cell type might succumb.
Where does Metaplasia occur?
(Ex: lung tissue of smokers, makes it better able to survive. Stratified squamous epithelial cells change to the ciliated columnar epithelial cells.)
What is Dysplasia?
Deranged cell growth of a specific tissue that results in cells that vary in size, shape, and organization.
What causes Dysplasia?
Chronic irritation and inflammation.
Where does Dysplasia occur?
Most frequently in areas of metaplastic squamos epithelium in the respiratory tract ad uterine cervix. (Ex: can detect pre-cancerous cells in cervix)
Which cells usually adapt by hypertrophy?
skeletal and cardiac muscles
Examples:
Urinary bladder thickens from long term obstruction of urinary outflow.
Myocardio hypertrophy results from valvular heart disease of hypertension.
Kidney enlarging of another is removed.
Which cells usually adapt by hyperplasia?
Epidermis, intestinal epithelium, and glandular tissue.
What is an intracellular accumulation?
The buildup of substances that cells cannot immediately dispose of.
What are come examples of intracellular accumulation?
Fatty changes in the liver due to intracellular accumulation of triglycerides. When the delivery of free fatty acids to the liver is increased as in starvation and diabetes. Also occurs with alcoholism which promotes a fatty liver.
Red blood cells break open (hemolytic anemia, release bilirubin, and causes jaundice)
Hypercholesterolemia increases LDL and causes atherosclerosis.
What is Dystrophic Calcification?
The macroscopic deposition of calcium salts in injured tissue.
What is Metastatic Calcification?
Increased serum calcium levels in normal tissue.
What are the causes of cellular injury?
Physical agents
Radiation
Chemicals
Biologic agents
Nutritional imbalances
Anything that hurts us hurts _______ first!
cells
Three main mechanisms of cellular injury....
1) free radical injury
2) hypoxic injury
3) impaired calcium homeostasis
What is free radical injury?
Unpaired electron
What is hypoxic injury?
Cell is deprived of oxygen and interrupts oxidative metabolism and the generation of ATP.
What is impaired calcium homeostasis?
Damaged cells accumulate Ca which activates digestive enzyme and the cell digests itself.
Reperfusion injury is a kind of ____ _______ injury.
free radical
Relate the significance of ion pumps in hypoxic injury....
when cell doesn't get oxygen (anaerobic), decrease in ATP which fails the Na/K pump. Na builds up inside cell, water follows solute, cell swells and may die.
3 outcomes of cellular injury...
1) reversible cell injury
2) programmed cell death
3) necrosis
What is Reversible Cell Injury?
cellular swelling and fatty change, does not result in cell death.
What is Programmed cell Death?
Apoptosis, Cell Suicide.
Controlled autodigestion of cell components after the cell breaks apart.
Eliminated worn out or damaged cells.
Does not cause inflammation.
What is Necrosis?
Cell death in organ or tissue which is still part of living person.
Involves UNREGULATED enzymatic digestion of cell components.
Cell breaks open randomly and releases insides, causes inflammation
Example of apoptosis...
webbing between fingers in fetus.
nerve cells.
Example of necrosis....
gangrene

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