Chapter 2 Flashcards, Altered Cellular and Tissue Biology Environmental Agents
(68 cards)
What is cellular adaptation?
Cellular adaptation is an alteration that enables the cell to maintain a steady state despite adverse conditions.
What is atrophy?
Atrophy is a decrease in cellular size that can affect any organ, most commonly skeletal muscle, the heart, secondary sex organs, and the brain.
What are the mechanisms of atrophy?
The mechanisms of atrophy probably include decreased protein synthesis, increased protein catabolism, or both.
What is physiologic atrophy?
Physiologic atrophy occurs with early development, such as the involution of the thymus gland.
What is pathologic atrophy?
Pathologic atrophy occurs due to decreases in workload, use, pressure, blood supply, nutrition, hormonal stimulation, and nervous stimulation.
How does aging affect cells?
Aging causes brain cells and endocrine-dependent organs, such as the gonads, to become atrophic.
What is hypertrophy?
Hypertrophy is an increase in the size of cells caused by increased work demands or hormonal stimulation.
What are the characteristics of hypertrophy?
Hypertrophy can be physiologic or pathologic, with increased amounts of protein in the plasma membrane, endoplasmic reticulum, microfilaments, and mitochondria.
What is hyperplasia?
Hyperplasia is an increase in the number of cells caused by an increased rate of cellular division.
What is compensatory hyperplasia?
Compensatory hyperplasia enables certain organs to regenerate.
What is hormonal hyperplasia?
Hormonal hyperplasia is stimulated by hormones to replace lost tissue or support new growth, such as during pregnancy.
What is pathologic hyperplasia?
Pathologic hyperplasia is the abnormal proliferation of normal cells in response to excessive hormonal stimulation or the effects of growth factors on target cells.
What is dysplasia?
Dysplasia, or atypical hyperplasia, is an abnormal change in the size, shape, and organization of mature tissue cells.
Is dysplasia cancer?
Dysplasia is not cancer and may not progress to cancer; it can be completely reversible if it does not involve the entire thickness of the epithelium.
What is metaplasia?
Metaplasia is the reversible replacement of one mature cell type by another, sometimes less differentiated, cell type.
When does metaplasia occur?
Metaplasia is found in association with tissue damage, repair, and regeneration.
How does metaplasia develop?
Metaplasia develops from a reprogramming of stem cells existing in most epithelia or of undifferentiated mesenchymal cells in connective tissue.
What leads to injury of tissues and organs?
Injury to cells and to the extracellular matrix (ECM) leads to injury of tissues and organs, ultimately determining the structural patterns of disease.
What are the two types of cellular injury?
Injured cells may recover (reversible injury) or die (irreversible injury).
What causes cellular injury?
Cellular injury is caused by a lack of oxygen (hypoxia), free radicals, caustic or toxic chemicals, infectious agents, unintentional and intentional injury, inflammatory and immune responses, genetic factors, insufficient nutrients, or physical trauma.
What are the types of cell injury?
Cell injury can be acute or chronic, and it can be reversible or irreversible.
What are the four biochemical themes important to cell injury?
The four biochemical themes are: (a) depletion of ATP, (b) decreased levels of oxygen and increased levels of oxygen-derived free radicals, (c) increased concentration of intracellular calcium and loss of calcium steady state, and (d) defects in membrane permeability.
What is the sequence of events leading to cell death?
The sequence includes decreased ATP production, failure of active transport mechanisms, cellular swelling, detachment of ribosomes, cessation of protein synthesis, mitochondrial swelling, vacuolation, leakage of digestive enzymes, autodigestion, lysis of the plasma membrane, and death.
What is the initial insult in hypoxic injury?
The initial insult is usually ischemia—the cessation of blood flow into vessels that supply the cell with oxygen and nutrients.