Questions and Answers
What responses can occur when there is cellular stress?
Adapt or die
What are 5 types of cellular adaptation?
Atrophy, hypertrophy, hyperplasia, dysplasia, metaplasia
What is atrophy?
Decrease in cell size
When does physiologic atrophy occur?
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Give an example of physiologic atrophy.
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When does pathologic atrophy occur?
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What is hypertrophy?
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What are two triggers for hypertrophy?
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Give an example of physiologic hypertrophy.
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Give 2 examples of pathologic hypertrophy.
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What is hyperplasia?
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Give an example of physiologic hormonal hyperplasia.
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Give an example of physiologic compensatory hyperplasia.
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What is pathologic hyperplasia?
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What triggers pathologic hyperplasia?
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Give an example of pathologic hyperplasia.
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What is dysplasia?
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Where does dysplasia often occur?
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What is an example of pathologic dysplasia?
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What is metaplasia?
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Give an example of metaplasia.
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What are the causes of cell injury?
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What is hypoxia?
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What is ischemia?
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What is a free radical?
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What are some examples of chemical cellular injury?
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What are some examples of radiation cellular injury?
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What is hypothermia?
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What is hyperthermia?
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What is a contusion?
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What is a hematoma?
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What is an abrasion?
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What is a laceration?
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What is an incised sharp injury?
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What is a stab wound?
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What is a puncture wound?
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Study Notes
Cellular Stress and Adaptation
- Responses to cellular stress can lead to adaptation or cell death.
- Five types of cellular adaptation: atrophy, hypertrophy, hyperplasia, dysplasia, and metaplasia.
Atrophy
- Atrophy is characterized by a decrease in cell size.
- Physiologic atrophy occurs during early development.
- Example: Thymus reduction in size with age during childhood.
- Pathologic atrophy is caused by:
- Disuse of organs or tissues.
- Lack of nerve stimulation.
- Loss of endocrine stimulation (e.g., vagina, uterus, gonads).
- Inadequate nutrition.
- Ischemia (decreased blood flow).
Hypertrophy
- Hypertrophy involves an increase in cell size due to increased workload demand.
- Two main triggers for hypertrophy:
- Mechanical signals.
- Trophic signals (growth factors, hormones, vasoactive agents).
- Physiologic hypertrophy examples:
- Increased muscle mass from exercise.
- Growth of uterus and mammary glands during pregnancy.
- Pathologic hypertrophy can occur when:
- A limb is immobilized, causing compensatory growth in the non-injured limb.
- A kidney takes on more workload after the loss of another kidney.
Hyperplasia
- Hyperplasia is the excessive proliferation of cells, resulting in an increased number of cells.
- Physiologic hormonal hyperplasia: uterus during pregnancy and thickening of mammary glands and endometrium.
- Physiologic compensatory hyperplasia: liver regeneration and skin calluses.
- Pathologic hyperplasia is the abnormal growth of normal cells, increasing the risk of cancer. Triggers include:
- Excessive hormone stimulation.
- Effects of growth factors.
- Example of pathologic hyperplasia: endometriosis.
Dysplasia
- Dysplasia involves abnormal changes in cell size, shape, and organization, with an increased cancer risk, though it can revert to normal.
- Commonly occurs in the cervix and respiratory tract.
- Pathologic dysplasia example: cervical cells becoming abnormal due to viral infection.
Metaplasia
- Metaplasia is the reversible replacement of one mature cell type by another.
- Example of metaplasia: Chronic irritation from smoking leading to the replacement of mucus-producing cells with non-mucus-producing cells. This can be reversed if smoking is stopped.
Cell Injury and Causes
- Causes of cell injury include:
- Hypoxic injury (most common, usually due to ischemia).
- Free radicals.
- Chemicals (e.g., medications, lead, carbon monoxide).
- Radiation (UV, ionizing, non-ionizing).
- Physical injury and nutritional imbalances.
- Genetic abnormalities.
- Biological agents (e.g., bacteria).
- Hypoxia refers to a lack of oxygen to cells.
- Ischemia indicates reduced blood supply.
Free Radicals and Chemical Injury
- Free radicals are uncharged atoms or groups with unpaired electrons, causing cellular damage by stealing electrons from neighboring atoms.
- Examples of chemical cellular injury:
- Medications like Tylenol.
- Lead (especially harmful to children).
- Carbon monoxide, ethanol (alcohol), and mercury.
Radiation and Physical Injuries
- Examples of radiation cellular injury:
- UV (sun exposure, tanning beds).
- Ionizing (x-rays, CT scans).
- Non-ionizing (microwaves, cell phones).
- Types of physical injuries include:
- Contusion: bruising with bleeding into skin or tissues.
- Hematoma: collection of blood in a confined space (e.g., brain).
- Abrasion: removal of the superficial layer of skin due to friction.
- Laceration: tearing or ripping of skin, resulting in jagged wounds.
- Incised wound: longer on the surface than deep.
- Stab wound: deeper relative to length on the surface.
- Puncture wound: sharp points without sharp edges (such as nails).
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Test your knowledge on cellular adaptation concepts with these flashcards. Covering types of adaptations like atrophy and hypertrophy, this quiz provides a quick review of critical cellular responses to stress. Perfect for students studying cellular biology.