Atrophy: decrease or shrinking cell size, can lead to whole organ shrinking - Loss of neurons in the brain (alzheimers) - Parapalegic - muscles in their lower body shrink due to lack of use Hypertrophy: increase in the size of cells/ organ - Increase in protein in cellular components - Skeletal muscle, heart - congestive heart failure - causes myocardial cells to enlarge Hyperplasia: increase in number of cells - example keloids, growth hormones Metaplasia and Dysplasia: abnormal changes in shape, size or organization of cells - Does not indicate cancer, underlying cellular structure is more organized - Dysplasia are the most unorganized, more severe than metaplastic
Full Answer
Altered Cellular and Tissue Biology. Injury to cells and their surrounding environment, called the extracellular matrix, leads to tissue and organ injury. Although the normal cell is restricted by a narrow range of structure and function, it can adapt to physiologic demands or stress to maintain a steady state called homeostasis.
Cellular Adaptation. Cellular adaptations, however, are a common and central part of many disease states. In the early stages of a successful adaptive response, cells may have enhanced function; thus it is hard to differentiate a pathologic response from an extreme adaptation to an excessive functional demand.
The most significant adaptive changes in cells include atrophy (decrease in cell size), hypertrophy (increase in cell size), hyperplasia (increase in cell number), and metaplasia (reversible replacement of one mature cell type by another less mature cell type).
The most important changes are nuclear; clearly, without a healthy nucleus, the cell cannot survive. Cellular aging causes structural and functional changes that eventually lead to cellular death or a decreased capacity to recover from injury.
Cellular swelling due to water influx (earliest manifestation of cell injury) Hydropic change or vacuolar degeneration: small, clear vacuoles within the cytoplasm (from distended ER) Plasma membrane.
If enough cells in an organ undergo atrophy the entire organ will decrease in size. Thymus atrophy during early human development (childhood) is an example of physiologic atrophy. Skeletal muscle atrophy is a common pathologic adaptation to skeletal muscle disuse (commonly called "disuse atrophy").
Overview: The four basic types of cellular adaptation to be discussed in this section are hyperplasia, hypertrophy, atrophy, and metaplasia.
Cellular swelling is the first manifestation of almost all forms of injury to cells. When it affects many cells in an organ, it causes some pallor, increased turgor, and increase in weight of the organ.
Five major types of adaptation include atrophy, hypertrophy, hyperplasia, dysplasia, and metaplasia.
Injurious stimuli trigger the process of cellular adaptation, whereby cells respond to withstand the harmful changes in their environment. Overwhelmed adaptive mechanisms lead to cell injury. Mild stimuli produce reversible injury. If the stimulus is severe or persistent, injury becomes irreversible.
Cellular adaptation is the ability of cells to respond to various types of stimuli and adverse environmental changes. These adaptations include. hypertrophy. (enlargement of individual cells), hyperplasia.
When cells adapt to injury, their adaptive changes can be atrophy, hypertrophy, hyperplasia, or metaplasia. Injured cells may also accumulate materials including fat, cholesterol, protein, glycogen, or pigment.
2. What are the common characteristics between the different mechanisms of cellular adaptation? What are the differences? Common characteristics include the ability of cells to respond to varying conditions with transduction of signals resulting in a change in gene expression.
Hypoxia is the most important cause of cell injury.
Generally, stimuli that cause cellular injury include immunological reactions (hypersensitivity reaction to foreign agents, autoimmune reactions, immune deficiency), nutritional imbalances (protein calorie malnutrition, excessive intake of fats, carbohydrates, and proteins), genetic defects (inborn errors in metabolism ...
Causes of cell injuryOxygen deprivation. A hypoxic state results in reduced aerobic oxidative respiration, which results in cell injury. ... Physical agents. ... Chemical agents and drugs. ... Immunologic reactions. ... Infectious agents. ... Nutritional imbalances. ... Genetic derangement. ... Hypoxia and ischemic cell injury.