Cell Adaptations Flashcards
At what stages in the cell cycle are the checkpoints?
End of metaphase
G1
G2
What is checked at mataphase?
Choromosome spindle attachment
What is checkt at G1?
DNA damage
What is checked at G2?
DNA replication
Cell size
What happens if damage is found in the cell cycle?
P50 protein activated
Repair or apoptosis
How is the cell cycle controlled?
CDK binding with cyclin to activate and allow cell entry into the next phase.
Multiple types of cyclin
What is hyperplasia?
Increase in cell number
What are physiological causes of hyperplasia?
Hormonal- eg, breat tissue after birth to allow for lactation to occour
Compensastory- aftr tissue damage to incrase tissue mass
What are pathological causes of hyperplasia?
Psoriasis- causing thickening of the epidermis
What is hypertrophy?
Increase in tissue/ organ size due to an increase in cell size
What does hypertrophy occour?
Increased functional demand
Incraesed hormonal stimulation
Which cell populations does hypertrophy occour in?
Labile, stabile and permenant
What are physiological causes of hypertrophy?
Skeletal muscle- weight lifters
Pregnant uterus- enlarges up to 70 times
What are pathological causes of hypertrophy?
Cardiac muscle hypertrophy- response to hypertension (incraesed resistance)
Smooth muscle hypertrophy- in intestinal stenosis, muscle contract harder to move contense
What is Atrophy?
Shrinkage of tissue/ organs due to decrease in size or number of cells
What causes atrophy?
Decrease in nutrients or growth factors
What is organ atrophy?
Combination of cellular atrophy and apoptosis
Cellular atrophy- shrinkage to size where cells can still survive
What are physiological causes of atrophy?
Postpartum atrophy of uterus after giving birth
What are pathological causes of atropohy?
Many causes;
Atrophy of diseases (reduced functional demand)- eg muscles immobile
Denervation atrophy (loss of inervation)
Inadiquate blood supply
Pressure- from tumor
Toxic agents- on bone marrow and testes
Xrays- cause direct cellular damage
What is metaplasia?
Reversible replacement of one differentaited cell type with another.
Where does metaplasia occour?
Within epethelia and connetive tissues
How does metaplasia occour?
By expressing a new genetic programme to allow cells to have a new structure/ function more suited to an altered environment
Useful examples of metaplasia?
Myeloid metaplasia of spleen:
If bone marrow destroyed then the spleen can produce more.
Renal pelvis and renal stones
What is an reversible form of metaplasia?
Connective tissue being turned to bone following trauma.
Normally revesible and resolves on its own
