Lecture 12 - Cellular Adaptations Flashcards
What determines the size of a cell population in an a adult?
Rate of cell:
-Proliferation
-Differentiation
-Death by apoptosis
When do cell numbers in a population increase?
Increased cell proliferation
Decreased cell death
Where can receptors be that regulate gene expression stimulating or inhibiting cellular proliferation?
Inside cell
On cell membrane
What genes regulate normal cell proliferation?
Proto-oncogenes
Tumour suppressor genes
What happens to a cell once it has completed a full cell cycle?
Renters G1
Leaves at G0
What is the type of differentiation which makes a cell permanently leave the cell cycle?
Terminal differentiation
What are the 3 parts to Interphase?
G1
S (DNA Synthesis)
G2
What is the protein which suppresses the cell cycle?
P53 protein
What is the point of checkpoints in the cell cycle?
Sense damage to DNA
What are the checkpoints in the interphase stage of the cell cycle?
G1 Checkpoint
G2 Checkpoint
What is the function of the G1 checkpoint?
Checks for DNA damage before replication
What is the function of the G2 checkpoint?
Checks DNA after replication
Checks cell size
What is the name of the proteins which drive cell cycle by phosphorylation of proteins?
Cyclin Dependant Kinases (CDK)
What is the Cyclin Dependant Kinase which allows for DNA replication to take place?
CDK4
How does CDK4 allow for DNA replication to take place?
CDK4 inactivates Rb
Rb inactivates/prevents DNA replication
What is the effect of CDK inhibitors on the cell cycle?
CDK always activated, meaning Rb always inactivated so cell cycle is driven .
Rb not able to inhibit cycle
What is cell adaptation?
The state between a normal unstressed cell and an overstressed injured cell
What are the 4 important types of cell adaptation?
- Hyperplasia
-Hypertrophy
-Atrophy
-Metaplasia
What is Hyperplasia?
Increase in number of cells
What is Hypertrophy?
Increase in cell size WITHOUT increase in cell number
What is Atrophy?
Decrease in cell size and or cell number
What is metaplasia?
Cells are replaced by cells of a different cell type
In hyperplasia, what are the reasons that hyperplasia may take place?
Increased functional demand
External stimuli
What type of tissues can hyperplasia take place?
Labile tissues
Stable tissues
What is neoplasia?
Irreversible hyperplasia that is irreversible
What triggers hyperplasia to take place?
Hormones (hormones that inc functional capacity)
Compensatory (inc in tissue mass after tissue damage)
What 2 hormones lead to the physiological hyperplasia of breast tissue?
Prolcatin
Oxytocin