Quiz Flashcards
(22 cards)
What are cellular adaptations?
Cellular adaptations are reversible functional and structural responses to physiologic stresses and some pathologic stimuli, aimed at preserving cell viability through new, altered steady states.
What are the types of cellular adaptations?
The types of cellular adaptations include:
1. Hypertrophy (increase in cell size)
2. Hyperplasia (increase in cell number)
3. Atrophy (decrease in cell size and metabolic activity)
4. Metaplasia (change in cell phenotype)
5. Dysplasia (change to an abnormal cell type)
What is hypertrophy, and when does it occur?
Hypertrophy is the increase in cell size, resulting in organ enlargement, often due to increased functional demand or hormonal/growth factor stimulation. It can be physiologic or pathologic.
Provide an example of physiologic hypertrophy.
Physiologic hypertrophy occurs in skeletal muscles in response to exercise, where muscle cells synthesize more proteins, increasing the force each myocyte can generate.
Example sentence
What is pathologic hypertrophy? Provide an example.
Pathologic hypertrophy occurs as a response to chronic conditions, such as the thickening of the left ventricular wall due to hypertension or faulty valves.
Define hyperplasia and its types.
Hyperplasia is an increase in the number of cells in an organ or tissue, increasing its volume. Types include:
- Physiologic hyperplasia: Example - breast tissue enlargement during pregnancy.
- Pathologic hyperplasia: Example - endometrial hyperplasia due to increased estrogen.
What mechanisms lead to atrophy?
Atrophy is caused by decreased protein synthesis due to reduced metabolic activity and increased protein degradation through the ubiquitin-proteasome pathway. It can also involve autophagy, with an increase in autophagic vacuoles.
Give an example of physiologic atrophy.
Physiologic atrophy includes the involution of the thymus in adults or the decrease in uterus size after childbirth.
What is metaplasia, and why does it occur?
Metaplasia is a reversible change where one differentiated cell type is replaced by another type that can better withstand adverse conditions. It results from stem cell reprogramming due to environmental signals such as cytokines and growth factors.
What is dysplasia?
Dysplasia refers to abnormal cellular proliferation, often due to chronic irritation or inflammation, and can be a precursor to cancer. It features cellular pleomorphism, loss of polarity, and nuclear hyperchromasia.
What is the fundamental cellular change associated with atrophy?
The fundamental change is a decrease in cell size and organelles, which reduces the metabolic needs of the cell, permitting its survival.
What are the causes of pathologic atrophy?
Pathologic atrophy can be caused by:
1. Inadequate nutrition
What is the fundamental cellular change associated with atrophy?
The fundamental change is a decrease in cell size and organelles, which reduces the metabolic needs of the cell, permitting its survival.
Example sentence: Atrophy can be seen in muscle cells during prolonged bed rest.
What are the causes of pathologic atrophy?
Pathologic atrophy can be caused by:
1. Inadequate nutrition
2. Decreased workload (disuse atrophy)
3. Loss of innervation (denervation atrophy)
4. Diminished blood supply
5. Loss of endocrine stimulation
6. Pressure
Example sentence: Denervation atrophy occurs in skeletal muscles due to loss of nerve supply, leading to decreased muscle mass.
Give an example of denervation atrophy.
Denervation atrophy occurs in skeletal muscles due to loss of nerve supply, leading to decreased muscle mass.
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What is metaplasia, and what is its primary mechanism?
Metaplasia is the reversible replacement of one differentiated cell type by another. It occurs through reprogramming of stem cells or undifferentiated mesenchymal cells by signals from the environment, such as cytokines or growth factors.
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What is an example of epithelial metaplasia?
An example is the replacement of normal columnar epithelium with squamous epithelium in the bronchi of smokers, where the squamous epithelium is more resistant to smoke.
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What characterizes dysplasia at the cellular level?
Dysplasia is characterized by:
- Hyperplasia of epithelial cells
- Loss of cell polarity (disorganized arrangement)
- Cellular pleomorphism (variability in cell size and shape)
- Nuclear hyperchromasia (dark-staining nuclei)
- Increased mitotic activity
Example sentence: Dysplasia can be observed in cervical cells with changes indicating possible progression to cancer.
How does dysplasia differ from cancer?
Dysplasia refers to abnormal cell growth but is not cancerous by itself. However, it can be a precursor to cancer if left unchecked.
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What are some examples of physiologic atrophy?
Examples include the involution of the thymus in adulthood and the reduction in uterus size after childbirth.
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How does metaplasia act as a double-edged sword?
Metaplasia is protective, as it replaces vulnerable cells with more resistant ones, but it also increases the risk of malignant transformation.
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What is physiologic hyperplasia, and give an example?
Physiologic hyperplasia is a normal increase in cell numbers, such as the enlargement of the liver after partial hepatectomy or the breast tissue during pregnancy.
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