Flashcards in The Cell Cycle And Cellular Adaptations Deck (24):
What are the different stages of the cell cycle and their checkpoints?
G1–> synthesis phase—> G2–> mitosis—> G1
G1 checkpoint- is the cell big enough to divide? Is the environment favourable? Is DNA damaged?
G2 checkpoint?- is all DNA replicated? Is the cell big enough?
What are CDK proteins?
They allow the cell to progress from one stage to the next
They become active by binding to cyclin proteins
What is RB protein?
A tumour suppressor protein which prevents excessive mitosis
Why is hyperplasia?
Increased cell divisions to increase tissue size by an increase in cell number
Which tissues can undergo hyperplasia?
Labile or stable tissues
What is a physiological example of hyperplasia?
Proliferation of the endometrium under influence of oestrogen
What is a pathological example of hyperplasia?
What is hypertrophy?
An increase in tissue or organ size due to increased cell size
Which tissues can undergo hypertrophy
Labile, stable and especially permanent tissues
What is a physiological example of hypertrophy?
Skeletal muscle, pregnant uterus
What is a pathological example of hypertrophy?
Right ventricular hypertrophy
What is compensatory hyperplasia?
The increase in size of an organ or tissue to compensate for a lack of function in the body
What is atrophy?
Shrinkage of an organ or tissue due to an acquired decrease in size/number of cells
What is a physiological example of atrophy?
Ovarian atrophy in post menopausal women
What is a pathological example of atrophy?
Muscle atrophy with disuse/dennervation/ inadequate blood supply
What is metaplasia?
Reversible change of one differentiated cell type to another
Why does metaplasia occur?
Substitution of cells that sensitive to stress by cell types better able to withstand the adverse environment
What are some example of metaplasia?
Barretts oesophagus- stratified squamous to glandular epithelium
Bronchial pseudostratified epithelium to stratified squamous epithelium due to cigarette smoke
What is reconstitution?
Replacement of a lost part of the body eg angiogenesis
What is aplasia?
Failure of a specific tissue or organ to develop
What is involution?
Programmed shrinkage of an organ. Eg uterus after childbirth, thymus in early life, pro and mesonephros
What is hypoplasia?
Underdevelopment of a tissue. Eg renal, breast, testicles in klinefelters syndrome
What is atresia?
No orifice. Eg congenital imperforation of anus, vagina, small bowel