Cellular Adaptation Flashcards
What is Cellular Adaptation?
The cell’s ability to maintain their structure/function when exposed to stressful situations and return to normal after the stimulus ceases.
When does Cell Injury or Death occur?
When the stress is too overwhelming
What do the molecular mechanisms that mediate cellular adaptations do?
Alter gene function (change depends on chemical messengers)
The genes that are altered are:
- Housekeeping (necessary for normal function)
2. Differentiating (differentiate characteristics of particular cell type)
In many cases _________ gene is altered. Why?
Differentiating
Cell can change size/form without compromising normal function
Implies that an organism remains within a certain range of physiological parameters to maintain stable function
Homeostasis
Implies that an organ constantly varies and adjusts physiological parameters to maintain stable function
Allostasis
Difference between homeostasis vs. allostasis
Homeostasis: Organism stays within a certain range
Allostasis: Constantly varies and adjusts
Decrease in cell size
Atrophy
Why Atrophy Responds
- Decrease in work demands
- Adverse environmental conditions
What happens in Atrophy?
Cells revert to smaller size and lower/more efficient level of functioning (compatible with survival)
Causes of Atrophy (5)
- Disuse
- Denervation
- Loss of Endocrine Stimulation
- Inadequate Nutrition
- Ischemia (decrease blood flow)
Increase in cell size with increase in functioning tissue mass
Hypertrophy
Reason for Hypertrophy
Increased workload imposed on an organ or body part
Where is Hypotrophy commonly seen?
Skeletal/Cardiac muscle-where muscle tissue cant form more cells by mitosis
Causes of Hypertrophy (2)
- Normal Physiological Conditions
- Abnormal Pathological Conditions
- Adaptive Hypertrophy
- Compensatory Hypertrophy
Normal Physiological Conditions
Increase mm mass associated with exercise
Adaptive Hypertrophy Examples
- Thickening of urinary bladder from long continued obstruction of urinary outflow
- Myocardial hypertrophy that results from heart disease or hypertention
Explain Compensatory Hypertrophy
Enlargement of a remaining organ or tissue after a portion has been removed or rendered inactive (Kidney removal)
Increase in the number of cells in an organ or tissue
Hyperplasia
Where does Hyperplasia occur?
In tissue with cells that can undergo mitosis
Epidermis, Intestinal Epithelium, Glandular Tissue
Causes of Hyperplasia
- Physiological Hyperplasia
a. Hormonal
b. Compensatory - Non-Physical Hyperplasia
a. Hormonal
b. Effects of Growth Factors on Target Tissue
(Is Reversible)
Breast/Uterine enlargement during pregnancy as a result of estrogen stimulation
Hormonal Physiological Hyperplasia
Regeneration of the Liver after partial hepatectomy or wound healing
Compensatory Physiological Hyperplasia
Abnormal menstrual bleeding as a result of too much estrogen
Hormonal Non-physiological Hyperplasia
Skin warts caused by growth factors produced by a certain virus
Effects of Growth Factors on Target Tissue (Non-Physiological Hyperplasia)
Reversible change in which one adult cell type is replaced by another
Metaplasia
Metaplasia occurs as a result of:
Chronic Irritation and Inflammation
Example of Metaplasia
Habitual Smoker: Stratified squamous epithelial cells into columnar epithelial cells
Deranged cell growth of a specific tissue. Results in cells varying in size, shape, and organization
Dysplasia