Class #3 Cellular Adaptation, Injury and Death Flashcards
Necessary genes for normal function of the cell
Housekeeping genes
Genes that determine the differentiating characteristics of a particular cell type.
Differentiating genes
The physiologic changes in the neuroendocrine, autonomic, and immune systems that occur in response to either real or perceived challenges to homeostasis.
Allostasis
Refers to decrease in cell size. It occurs in response to decrease in work demands or adverse environmental conditions. Cells revert to a smaller size and a lower and more efficient level of functioning that is compatible with survival.
Atrophy
Causes of atrophy are grouped into 5 categories:
- Disuse; e.g. in skeletal muscles
- Denervation; form of disuse atrophy that occur in muscles of paralyzed limb
- Loss of endocrine stimulation; loss of estrogens in menopausal women lead to atrophic changes in the uterus
- Inadequate nutrition; atrophic changes seen in malnutrition
- Ischemia or decrease blood flow; cell decreases their size and energy requirement as a means of survival.
Refers to increase in cell size with an increase in the amount in functioning tissue mass. Results from an increased workload imposed on an organ or body part.
Hypertrophy
Hypertrophy is commonly seen in __________and __________ tissue which cannot form more
cells by mitotic division.
skeletal muscle and cardiac muscle
Thickening of the urinary bladder from long-continued obstruction of urinary outflow is an example of:
Adaptive Hypertrophy
Valvular heart disease or hypertension may result in:
Myocardial hypertrophy
Enlargement of a remaining organ or tissue after a portion has been removed or rendered inactive e.g. of the only remaining kidney.
Compensatory hypertrophy
Refers to an increase in the number of cells in an organ or tissue
Hyperplasia
Two common types of Physiological hyperplasia:
- Hormonal – e.g. breast and uterine enlargement during pregnancy as a result of estrogen stimulation
- Compensatory – e.g. the regeneration of liver that occurs after a partial hepatectomy (partial removal of the liver); hyperplasia of connective tissue during wound healing
Refers to reversible changes in which one adult cell type is replaced by another adult cell type due to reprogramming of undifferentiated stem cells that are present in the tissue undergoing changes.
Metaplasia
An example of metaplasia is adaptive replacement of columnar epithelial cells by stratified squamous epithelial cells in the trachea and large airways of a habitual ______________
cigarette smoker.
Refers to deranged cell growth of a specific tissue that results in cells that vary in size, shape and organization.
Dysplasia
Refers to a change in the structure of cells and their orientation to each other that is characterized by a loss of cell differentiation, as in cancerous cell growth.
Anaplasia
Disintegration of cells into membrane-bound particles that are then phagocytised by other cells.
Programmed Cell Death
highly selective process that eliminates injured and aged cells, thereby controlling tissue regeneration.
Apoptosis
Two patterns of Reversible / Sub-lethal Cell Injury are observable:
Cellular Swelling and Intracellular accumulation
Glycogen, bilirubin, coal, dust, and silica are endogenous, exogenous sources of
Intracellular accumulation
Refers to cell death in an organ or tissue that is still part of living tissue
Necrosis
What is the difference between hypertrophy and hyperplasia?
Hypertrophy is increase in cell size.
Hyperplasia is increase in cell number.
Type of reversible/sub-lethal cell injury which usually occurs as the result of hypoxic cell injury (e.g. ischemia, virus, bacteria, chemical and biological toxins, extreme heat or cold, etc)
Cellular swelling
Disintegration of cells into membrane-bound particles that are then phagocytised by other cells is called ____________
Programmed cell death aka apoptosis
The number of cells in tissues is regulated by ____________
cell death.
Apoptosis is highly selective process that eliminates _______________, thereby controlling tissue regeneration.
injured and aged cells
__________ is responsible for many physiological processes, including:
Programmed destruction of cells during embryonic development
Hormone dependent involution of tissues
Death of immune cells
Apoptosis
Apoptosis is linked to many pathological processes and diseases such as (3 points):
Carcinogenesis
Viral infections such as hepatitis B and C that cause cell death
Neurodegenerative disorders, e.g. Alzheimer’s disease, Parkinson’s disease, and
ALS
____________ refers to cell death in an organ or tissue that is still part of living tissue
Necrosis
Necrosis differs from apoptosis in that it involves (4 points):
Unregulated enzymatic digestion of cell components
Loss of cell membrane integrity
Initiation of inflammatory response
Interference with cell replacement and tissue regeneration
___________ occurs when a considerable mass of tissue undergoes necrosis (usually due to deficient or absent blood supply)
Gangrene
Causes of aging are explained by a number of theories (4 points):
- Evolutionary theory: aging is a consequence of natural selection
- Molecular theory: aging occurs as a result of gene expression
- Cellular theory: aging occurs as a result of free radical damage or apoptosis
- System theory: cellular aging occurs due to a decline in the integrative functions of organ systems such as the neuroendocrine and immunological systems
________________ is not illness – it is a shrinkage of reserves, in real terms, but alsobecause the body is using more of its reserve capacities to function in everyday life.
Homeostenosis
The most common cause of cell injury. Caused by a lack of oxygen, respiratory disease, ischemia, anemia, physical or pathological injury to the oxygen delivery method
Hypoxia
Cell swelling, denaturation of enzymes, chromosome clumping, autolysis, and coagulative necrosis, are outcomes of
Hypoxia
Decreased O2 → impaired oxidative metabolism → decreased ATP = cell swelling. OR: anaerobic metabolism → increased lactic acid → decrease pH are the effects of
Hypoxia
Common causes of injuries due to environmental exposure, occupational and transportation accidents, and physical violence and assault.
Injury from Physical Agents
Mechanical forces, extremes in temperature and electrical injuries are examples of
Injury from Physical Agents
Type of radiation injury that removes electrons from atoms and molecules and can immediately kill cells,
interrupt cell replication, or cause a variety of genetic mutations, which may or may not be lethal.
Ionizing radiation
Which type of radiation is used in cancer treatments.
Ionizing radiation
Which cells are most vulnerable to ionizing radiation?
gastrointestinal tract, bone marrow, cells with high mitotic activity
Radiation in the ultraviolet band which at lower energies (left side of ultraviolet) is called non-ionizing radiation, while higher energies to the right side of the
ultraviolet band is called ionizing radiation.
Ultraviolet radiation
Which type of radiation causes sunburn and increases the risk of skin cancers
ultraviolet radiation
T/F: UV radiation damages DNA.
True
Type of radiation that includes infrared light, ultrasound, microwave, and laser energy
Non-ionizing radiation
Effect of this type of radiation is produced by causing vibration and rotation of atoms and molecules (causing hyperthermia)
Non-ionizing radiation
______________ can injure the cell membrane and other cell structure, block enzymatic pathways, coagulate cell proteins and disrupt the osmotic and ionic balance of the cell.
Chemical agents
Examples of __________ include:
a. Drugs
b. Lead toxicity
c. Mercury toxicity
Chemical Injury
_______ differ from other injurious agents in that they are able to replicate and can continue to produce their injurious effects.
Biological agents
