Cell responses to Injury I Flashcards
What can reversible cell injuries cause?
Pallor, Increased rugor, increased weight, generalised cell swelling and fatty changes
What is cell adaptation?
A reversible process that occurs to a cell when stress is applied that allows the cell to survive in changes of phsyiologic state
What is hypertrophy?
Increased cellular protein production that causes increased cell size and synthesis/ assembly of intracellular components and increased workload (due to increase in hormones)
What is hyperplasia?
Increased number of cells (driven by growth factors) and increased output of new cells and increased functional capacity of hormone sensitive organs (e.g estrogen during pregnancy)
What is atrophy?
a reduction in size and number of cells (driven by growth factors), decrease in protein synthesis and an increase in protein degredation
What are some pathologic causes of atrophy?
decreased worload, loss of blood supply, inadequate nutrition, pressure, senile atrophy, denervation atrophy
What are some physiologic causes of atrophy?
normal development
What is metaplasia?
When a mature cell is replaced by a different cell type, e.g smokers can gain squamous epithelium instead of cilliated
What is dysplasia?
an increase in the number of poorly differentiated cells (atypical) predisposes to neoplasia
How does being senile cause atrophy?
reduces the capacity to gain muscle
When does cell injury occur?
When a cell is unable to adapt
What can cause cell injury?
oxygen deprivation, physical/chemical agents
infectious agents/ immunologic reactions
What is Hypoxia?
oxygen deprivation, (reduction in aerobic respiration or reduction in blood flow ischaemia) inadequate oxygenation can be due to CO poisoning
What is reperfusion injury?
Restoration of blood flow to previously ischaemic tissues
What are the 3 different types of dysplasia?
Anisocytosis (change in nucleus), Poikilocytosis (change in cells), and Karyomegaly (nucleus becoming abnormally enlarged)
What is reperfusion injury?
Blood flow in a tissue that was previously exposed to ischaemia means you get a lot of dead inflammatory cells that create a lot of ROS
What are chemical agents?
directly toxic and can cause injury to the cell membrane, e.g a build up of mercury in tuna
What are some examples of physical agents?
mechanical, extreme temperatures (e.g enzyme damage), radiation and electric shock
What are some examples of infectious agents?
parasites, prions, viruses, bacteria and fungi
What are some genetic issues that can effect cells?
deficient protein missfolding, deficient protein function and damaged DNA
What is an example of an immunological reaction?
hayfever
What is the effect of obesity and malnutrition?
Malnutrition can lead to over/under conditioning which then leads to a cell that cannot grow/thrive
there is also a predisposition to disease
What is ROS?
an unstable molecule/ compind due to an electron in the outer shell- it is usually produced during normal respiration- if mitochondria is damaged it enters the cytosol and causes missfolding of proteins/ damages to DNA
What causes mitochondrial damage (a mechanism of cell injury)
comes from injurious (severe/persistent stimuli) like ROS or mutation of mitochondrial genes
What are the consequences of mitochondrial damage
ATP deletion, production of new channels or incomplete phosphorylation
What does disruption of biochemical pathways cause?
oxidative stress, disturbances in calcium homeostasis and endoplasmic reticulum (causes a reduction in protein production)
What does membrane damage cause?
causes ROS, decreased phospholipid synthesis and cytoskeleton abnormalities
What can cause damage to DNA?
Radiation, Drugs, ROS, Aging and Chemotherapeutics
Name 5 things that can cause free radicals to be generated
- Absorbance of radiant energy
- Activated leukocytes
- Enzymatic metabolism
- Transition metals
- Nitric oxide
Name 3 things that can cause mitochondrial damage
- Low Oxygen supply
- Toxins
- Radiation
Name three things that can disrupt biochemical pathways
- Calcium homeostasis
- Endoplasmic retciulum stress
- Oxidative stress
Name 4 things that can cause membrane damage
- ROS
- Decreased phospholipid synthesis
- Incresaed phospholipid breakdown
- Cytoskeletal abnormalities
Name 3 membranes that can be affected by membrane damage
- Mitochondrial membrane
- Plasma membrane
- injury to lysosomal membrane
Name 5 things that can damage DNA
- Radiation
- Drugs
- ROS
- Aging
- Chemotherapeutics
When is ROS created?
ROS is always created but damage to the mitochondria may mean that ROS cannot be eliminated
