How is cell cycle controlled? (3)
Cyclin protein & CDK enzymes!> form complex
Activated CDK’s Phophorylate protiens
ex: Retinoblastoma (Rb), that is critical fro the preogression of the cell cycle to the next stage!
This complex is controlled by GF or CDK inhibitors.

What can the chemical signals make the cell do?
Survive the 2 D’s

How can a cell population increase it’s numbers?
v
Can cells with damaged DNA replicate?
if there is damage to the DNA, or the DNA hasnt replicated, then the cell will try and fix it, if it cant fix it, it’ll push itself into aopotosis.
but in general NO. it cant replicate!
what is the most important check point in the cell cycle? where is it in the cell cycle
The restriction (R) point, near the end of G1!
after it passed the R point, the cell doesn’t need further signals to carry on, it can now complete the cell cycle on its OWN!
(cell isnt restricted anymore)

what is a telemere? telemorase
Telemorase is an enzyme that grows back the “telomeres” (plastic bit at the end of a shoe lace ;P)
they sit in the end of ur chromosome, and everytime a cell divides, they get shorter and shorter.

Are cellular adaptations reversible?
v
What is hyperplasia? In which types of tissues does it occur?
Increase in tissue or organ size due to increased cell #’s.
What examples are there of physiological hyperplasia?
What examples are there of pathological hyperplasia?

What is hypertrophy? In which types of tissue does hypertrophy occur?
Increase in tissue or organ size due to increased cell SIZE and NOT #’s
What examples are there of physiological hypertrophy?

What examples are there of pathological hypertrophy? (3)

But don’t athletes get cardiac muscle hypertrophy?
But that not a problem, bc after he’s done running, hes gunna lay down, and his heart can rest!

What is atrophy?
Shrinkage of a tissue or organ due to an acquired decrease in size and/or number of cells
What is happening in the cell in atrophy?
A-trophia >> means lack of food.
shrinkage of a tissue or organ due to lack of nutrients and or GF
What examples are there of physiological atrophy?
Give example of atrophy that may occur in the pancreas
ex: ur pancreas is obstructed by a stone, it will cause the pancreas tissue to atrophy. the islets of langerhans get left behind. and fibrotic tissue is present.
Cerebral atrophy ex?
– Alzheimer’s disease
What examples are there of pathological atrophy?
-If u stopped using a muscle>> u get atrophy of a mUscle! It is reversible with imcreased activity! Reduced functional demand/workload = atrophy of disuse: muscle atrophy after disuse, reversible with activity
***But some organs r protected ( ex brain. It is that last to get into malnutritiion!)
What is aplasia? give examples
Complete failure of a specific tissue or organ to develop
it is an embryonic developmental disorder
Eg:
(Also used to describe an organ whose cells have ceased to proliferate, e.g. aplasia of bone marrow in aplastic anaemia)
What is hypoplasia? examples
Congenital Underdevelopment or incomplete development of tissue or organ at embryonic stage, inadequate number of cells.
In a spectrum with aplasia NOT opposite of hyperplasia as it is a congenital condition.
Cf atrophy which occurs when existing part wastes away.
Eg: Rena,l Breast , Testicular in Klinefelter’s syndrome. Chambers of the heart
What is metaplasia? examples ? Does metaplasia predispose to cancer?
Reversible replacement of one cell by another.
(the stem cells that r producing a specific type of cells SWITCH paths! and start producing a different line of cells)
-Metaplastic cells are fully differentiated and the process is reversible
**with smoking, u get change of the pseudostratified columnar cells into stratified squamous cells YES