Cells adapt to stimulus by changing...
Size, number, and/or mophology
True/False: Changes made by cells under stress are always reversible.
False. Changes are reversible if stimulus is not too severe and not long lasting. If stimulus is severe or long lasting changes may not be reversible.
Define Atrophy vs Hypertrophy
Atrophy: decrease in cell size
Hypertrophy: increase in cell size
List some causes of atrophy
Disuse, denervation, loss of endocrine stimulation, inadequate nutrition, and/or ischemia (decreased blood flow)
What are some causes of cell hypertrophy?
Exercise, increased workload, disease
Define hyperplasia:
increase in cell number
Explain the two causes of hyperplasia in cells
Physiologic: from hormones or increased workload
Non-physiologic: exogenic androgens
True/false: Hyperplasia and hypertrophy never occur together
False! They often occur together and can cause an organ to become enlarged.
Hyperplasia--->Hypertrophy
What are the 4 primary types of tissue?
Connective
Epithelial
Muscle
Nervous
**each tissue type has subtypes
Define Metaplasia:
Adult cell type changes into a different adult cell type within the same primary tissue
Only ___ and some _____ tissue undergo metaplasia.
Epithelium and some connective tissue
What commonly causes metaplasia in cells?
Chronic irritation and inflammation
*Might predispose to cancer
What is dysplasia?
deranged cell division and/or cell growth so cells vary in size, number, morphology and arrangement to one another
Caused by chronic irritation and inflammation
May predispose to cancer!
What is intracellular accumulations?
Subrstance build up within the cytoplasm, organelles, or nucleus of the cell
Intracellular accumulations can come from the following three things:
1. Normal substances: lipids, proteins, carbs, melanin, bilirubin
2. Abnormal substances: excessive glycogen in cells of liver and kidney
3. Exogenic substances: environmental toxins, exogenous pigments
What is Lipofuscin (in relation to intracellular accumulations) ?
endogenous pigment from lysosomes
"wear and tear" pigment
most common in heart, nerve, and liver cells
Can intracellular accumulations be reversible? Explain.
Yes, if the accumulation reflects a correctable systemic disorder such as seen in jaundice
Give an example of a disease that results in intracellular accumulation?
Tay sachs disease
Accumulates abnormal glyolipids in brain cells
Pathologic calcifications from calcium salts, iron, magnesium and other mineral salts is _____?
Abnormal!!
adaptive response of a cell to a change
Metastatic calcifications occur in (abnorma/normal) cell tissue are a result of _______.
Normal cells; from hypercalcemia
Give the 5 main categories of agents that cause cell damage
1. Physical agents
2. Radiation
3. Chemical agents
4. Biological agents
5. Nutritional imbalances
Name the three most common mechanisms of cell injury:
1. Free radical formation: extra unpaired electrons
2. Hypoxia (lowered O2): ischemia, lowered blood flow which leads to hypoxia
3. Increased Ca++ intracellular concentration
List four ways to cause hypoxia:
1. decreased hemoglobin (low iron) or abnormal hemoglobin (sickle cell anemia) so cells don't load with normal amounts of 02
2. Decreased Oxygen inspiration: high elevation
3. Edema in lungs from high BP or trauma, causes less diffusion of O2 in lung capillaries
4. Blockage/damage of vessels in local area
List 2 reversible cell injuries observed under the microscope:
1. cell swelling from lack or ATP to run NA+/K+ ATPase pumps to maintain normal concentrations caused by hypoxia
2. Intracellular accumulation of fat -usually in liver, kidneys and heart
_____ _____ is the first manifestation to almost all forms of injury to cells
Cellular swelling
seen under the microscope as small, clear vacuoles within cytoplasm
What are the two types of cell death?
Apoptosis and necrosis
Apoptosis:
programmed cell death that occurs at a certian cell age
True/false: Apoptosis elicits inflammation
False. fragments of dead cell are rapidly cleared before cytoplasmic contents have leaked out
Give an example of apoptosis in development
The development of the hand in the human embryo--webbed hands progress to non-webbed.
Necrosis:
death of cells in tissues of organs that are part of a living individual
Which type of cell death causes inflammation?
a. apoptosis
b. necrosis
b. necrosis
How is necrosis different from apoptosis?
plasma membrane not kept intact
necrosis interferes with cell replication/replacement as well as cell healing
Explain liquefaction necrosis vs coagulation necrosis
liquefaction necrosis damage neighboring cells so there is no remaining cellular outlines, and results in gooey, semi-fluid area.
Coagulation necrosis due to acidosis, basic cell shape preserved, firm
Caseous necrosis:
"cheese-like", soft are seen in TB lesions
What type of coagulation is characteristic of hypoxic injury?
Coagulation necrosis
Explain the two types of gangrene: dry vs wet
Dry: form of coagulation necrosis, dry, shriveled and wrinkly, spreads slowly
Wet: form of liquefaction necrosis, moist, swollen, turgid, spreads rapidly
How can dry gangrene progress to wet gangrene?
If bacteria invades the necrotic area the gangrene may convert to wet, which can cause systemic effects that may lead to death
Explain the characteristics of gas gangrene
results from necrotic tissue being infected by gas producing bacteria
most commonly Clostridium perfingens
Cells begin to age within the ___ decade, causing a decline in the following areas:
4th decade,
Decrease in muscle strength, cardiac reserve, vital capacity, nerve conduction time, and glomerular filtration rate
What causes cell aging?
Thought to be a programmed genetic change
or accumulation of DNA mutations