Flashcards in Robbins Questions Deck (22):
What is Hypertrophy and what causes it?
Hypertrophy is increased cell or organ size often in response to increased workload.
*Induced by growth factors produced in response to mechanical stress or other stimuli
**Occurs in tissue incapable of cell division.
What is hyperplasia?
Increased number of cells in response to hormones and other growth factors; occurs in tissues whose cells are able to divide or contain abundant tissue stem cells
What is atrophy ?
Decreased cell or organ size as a result of decreased nutrient supply or disuse; associated with decreased synthesis of cellular building blocks and increased breakdown of cellular organelles.
What is metaplasia?
A change in phenotype of differentiated cells often in response to chronic irritarion that makes cells better able to withstand the stress
How does metaplasia occurs?
Induced by altered differentiation pathways of tissue stem cells. may result in reduced functions or increased propensity for malignant transformation.
What is a risk factor that metaplasia carries with it?
The influences that induce metaplastic change, if persistent, may predispose to malignant transformation of the epithelium
What type of cells make up the lower portion of the esophagus
Stratified Squamous Epithelium
In conditions of chronic gastric reflux what will this tissue undergo metaplastic transformation into?
Intestinal type columnar epithelium
What is associated with necrosis?
Loss of membrane integrity and leakage of cellular contents culminating in the dissolution of cells. Largely resulting from the degradative action of enzymes on lethally injured cells.
What is necrosis characterized by ( morphologically)
Changes in the cytoplasm and nucleus
What is liquifactive necrosis?
microbes stimulate the accumulation of inflammatory cels and the enzymes of leukocytes digest and liquify the tissue.
**If the process was initiated by acute inflammation the pus will be yellow.
What is fat necrosis?
refers to focal areas of fat destruction typically resulting from release of activated pancreatic lipase's into the substance of the pancreas and the peritoneal cavity.
What are the major causes of ATP depletion?
The major causes of ATP depletion are reduced supply of oxygen and nutrients, mitochondrial damage, and the actions of some toxins.
What are the three major cellular systems that will fail when ATP is depleted.
1. Teh activity of plasma membrane ATP dependent sodium pumps.
2. There is acomensatory increase in anaerobic glycolysis in an attempt to maintain the cell's energy sources.
3. Failure of ATP dependent Ca2+ pumpsleads to influx of Ca2+
What will prolonged depletion of ATP cause?
Structural disruption of of the protein synthetic apparatus manifested by detachment of ribosomes from the rough ER.
What is a respiratory burst?
A phagasome membrane enzyme catalyzes the generation of superoxide which is converted to peroxide that is then converted to hypochlorite.
What are the three ways reactive oxygen species cause damage to cells?
1. Lipid Peroxidation of membranes.
2. Cross-Linking and other changes in proteins
3. DNA damage.
What is ischemia?
reduced blood flow to tissue or an organ. Ischemia, because of reduced blood supply, also compromises the delivery of substrates for glycolysis.
What is worse, ischemia or hypoxia.
Ischemia because in cases of hypoxia anaerobic metabolism can take place. In ischemia anaerobic energy generation ceases because of reduced blood flow.
What is the most important biochemical factor in hypoxia?
The most important biochemical factor in hypoxic cells that leads to injury is reduced intracellular generation of ATP as a consequence of reduced supply of oxygen.
What is ischemic reprofusion injury?
Under certain circumstances the restoration of blood flow to ischemic but viable tissues results in the death of cells that are not otherwise irreversibly damaged.