7 Cell Adaptations Flashcards
After a signal, what are the 4 options a cell can take?
Resist apoptosis (survive)
Divide
Differentiate
Undergo apoptosis (die)
List 3 factors that determine the size of a cell population
Rate of cell proliferation
Cell differentiation
Cell death by apoptosis
What is:
i. ) Autocrine action
ii. ) Paracrine action
iii. ) Endocrine action
i. ) Secretion of a molecule that binds to its own receptors
ii. ) Secretion of a molecule that binds to a nearby cell
iii. ) Secretion of a molecule that travels in the circulation to a distant cell
What is a growth factor?
Local mediator involved in cell proliferation
Coded for by proto-oncogenes and are polypeptides that act on cell surface receptors.
How does increased growth occur?
The cell cycle is shortened
Quiescent cells are converted to proliferating cells
What is the most important check point in the cell cycle?
The restriction point (R)
What happens if the R checkpoint in the cell cycle is activated?
p53 triggers DNA repair mechanisms or apoposis
What is regeneration?
Replacement of cell losses by identical cells to maintain tissue and organ size.
What is reconstitution?
The replacement of a lost part of the body
Eg. a limb (only partially possible in humans)
What is hyperplasia?
Increase in tissue or organ size due to increased cell numbers
What is hypertrophy?
Increase in tissue or organ size due to increased cell size
What is atrophy?
Shrinkage of a tissue or organ due to an acquired decrease in size and/or number of cells
What is metaplasia?
Reversible change of one differentiated cell type to another
Give an example of metaplasia
Smoking causes pseudostratified ciliated epithelium in the bronchi to become stratified squamous epithelium.
What is hypoplasia?
Underdevelopment of a tissue or organ at the embryonic stage due to a lack of cells
