[PL2.1] CELL INJURY, CELL DEATH,& ADAPTATIONS

Reversible functional and structural responses to physiologic or pathologic changes

adaptations

Increase in the size of cells resulting in increased tissue or organ size

hypertrophy

Increase in the number of cells in a tissue or organ

hyperplasia

Decrease in the size and function of cells, tissues, or organs

atrophy

Reversible change in which one differentiated cell type is replaced by another cell type

metaplasia

Deficiency of oxygen that impairs aerobic oxidative respiration

hypoxia

Cause of hypoxia due to reduced blood flow

ischemia

Cause of hypoxia due to failure of heart or lungs

cardiorespiratory insufficiency

Cause of hypoxia due to low oxygen-carrying capacity of blood

anemia or CO poisoning

Type of injury caused by mechanical trauma or extreme temperatures

physical agents

Example of physical agent injury: burns or cold

extreme temperatures

Example of physical agent injury: sudden pressure changes

atmospheric pressure changes

Example of physical agent injury: electric shock

electric shock

Type of injury caused by glucose or salt in hypertonic concentrations

chemical injury

Effect of chemical agents that derange electrolyte and fluid balance

cell injury

High concentration of oxygen can cause what type of injury

chemical injury

Examples of toxic chemical agents: arsenic, cyanide, mercury

poisons

Environmental pollutants, insecticides, herbicides cause what type of injury

chemical injury

Industrial and occupational hazards that may lead to cell injury

CO or asbestos exposure

Recreational drugs and alcohol can result in what type of injury

chemical injury

Toxic side effects of therapeutic drugs may lead to what

chemical injury

Type of agent causing injury through bacteria, viruses, fungi, or parasites

infectious agents

Type of reaction causing cell injury in autoimmune diseases or response to external substances

immunologic reactions

Immune response directed against the body’s own tissues

autoimmune disease

Immune reaction to viruses or environmental substances

external immune reaction

Abnormalities in chromosomes or DNA sequences that lead to injury

genetic abnormalities

Example of genetic abnormality: extra chromosomes

genetic abnormality

Example of genetic abnormality: single base pair substitution causing amino acid substitution

genetic abnormality

Mechanism of injury: deficient protein function, inborn errors of metabolism, or accumulation of damaged DNA

protein/DNA abnormalities

Cause of cell injury due to insufficient intake or absorption of nutrients

nutritional deficiency

Examples of nutritional deficiency: protein, calorie, or vitamin deficiency

nutritional imbalance

Example of self-imposed nutritional deficiency

anorexia nervosa

Cause of cell injury due to excessive nutrient intake

nutritional excess

Example of nutritional excess: obesity

nutritional imbalance

Increased serum cholesterol predisposes to what condition?

atherosclerosis

Atherosclerosis is a risk factor for what disease?

cardiovascular disease

First detectable changes in cell injury progression

molecular or biochemical changes

Changes that take longer to appear in cell injury progression

light microscopic and gross morphologic changes

There is a time lag between what two events in cell injury progression?

stress and morphologic changes

Increase in cell size resulting in enlargement of an organ

hypertrophy

Does hypertrophy involve new cells?

no

What type of cells undergo only hypertrophy and not hyperplasia?

non-dividing cells (e.g. myocardial fibers)

What type of cells may undergo both hypertrophy and hyperplasia?

dividing cells

Common stimuli for hypertrophy

hormonal stimulation, increased functional demand, increased workload

Most common stimulus for hypertrophy of skeletal and cardiac muscle

increased workload

Pathologic hypertrophy example

enlargement of the heart due to hypertension or valvular disease

Physiologic hypertrophy example: uterus growth during pregnancy

hormonal stimulation

Physiologic hypertrophy example: muscle growth due to exercise

increased workload

Cause of physiologic hypertrophy

increased hormone stimulation and functional demand

Increase in the number of cells in response to a stimulus, leading to enlargement of tissue or organ

hyperplasia

Can hyperplasia and hypertrophy occur together?

yes

What type of cells can undergo hyperplasia?

dividing cells

Type of physiologic hyperplasia due to increased functional capacity of hormone-sensitive organs

hormonal hyperplasia

Example of hormonal hyperplasia: breast enlargement during puberty and pregnancy

hormonal hyperplasia

Example of hormonal hyperplasia: uterine enlargement during pregnancy

hormonal hyperplasia

Type of physiologic hyperplasia due to tissue regeneration after damage or resection

compensatory hyperplasia

Example of compensatory hyperplasia: liver enlargement after partial hepatectomy

compensatory hyperplasia

Example of compensatory hyperplasia: kidney enlargement after unilateral nephrectomy

compensatory hyperplasia

Hyperplasia occurs only in what kind of cells?

dividing cells

Which type of hyperplasia is triggered by hormone-sensitive organ growth?

hormonal hyperplasia

What type of hyperplasia occurs when tissue regenerates after loss or injury?

compensatory hyperplasia

What organ shows compensatory hyperplasia after partial hepatectomy?

liver

What organ shows compensatory hyperplasia after unilateral nephrectomy?

kidney

What is caused by excessive hormonal stimulation and excessive growth factors?

pathologic hyperplasia

what may become precursors to cancer development

pathologic hyperplasia

increased estrogen leads to ___

endometrial hyperplasia

endometrial hyperplasia leads to ___

cancer

increased androgen leads to ___

benign prostatic hyperplasia

papillomavirus leads to

skin wart

What is Reduction in the size of an organ or tissue due to a decrease in cell size and number?

Atrophy

What is common during normal development?

PhysiologicAtrophy

An example of this is Notochord and thyroglossal duct atrophy during fetal development

Physiologic Atrophy

An example of this is Thymic atrophy

Physiologic Atrophy

An example of this is Decrease in size of uterus after birth

Physiologic Atrophy

Type of atrophy caused by decreased workload, such as limb immobilization

disuse atrophy

Type of atrophy caused by loss of nerve supply

denervation atrophy

Type of atrophy caused by reduced blood flow, such as in atherosclerotic cerebrovascular disease

diminished blood supply

Type of atrophy caused by inadequate nutrient intake or absorption, e.g. marasmus or cachexia

inadequate nutrition

Type of atrophy due to decreased hormone levels, such as endometrial atrophy after menopause

loss of endocrine stimulation

Type of atrophy caused by compression from a mass such as a tumor

pressure atrophy

Example of disuse atrophy

limb immobilization

Example of atrophy from diminished blood supply

atherosclerotic cerebrovascular disease

Example of atrophy from loss of endocrine stimulation

endometrial atrophy post-menopause

Example of pressure atrophy

tumor compressing surrounding tissues

Reversible change where one differentiated cell type is replaced by another

metaplasia

Is metaplasia reversible or irreversible?

reversible

Most common epithelial metaplasia

columnar to squamous

Example of columnar to squamous metaplasia: respiratory tract of a habitual smoker

metaplasia

Condition where squamous epithelium transforms into columnar epithelium due to acid reflux

barrett esophagus

Cellular change that is a response to chronic irritation or inflammation

dysplasia

In dysplasia, cells change from a mature to what type?

immature

Is dysplasia an adaptive response?

no

Is dysplasia potentially reversible?

yes

Dysplasia is associated with what type of cellular transformation?

premalignant change

Type of metaplasia seen in Barret esophagus

squamous to columnar