2: Tissue and cell injury Flashcards
What is homeostasis?
Physiological process in which variables within the body are kept within a narrow range
What two processes do cells undergo when they are under increased demand?
Hyperplasia
Hypertrophy
What process do cells undergo when they are under decreased demand?
Atrophy
What process do cells undergo when they are exposed to altered stimuli?
Metaplasia
What is hypertrophy?
Increase in the size of cells
What is hyperplasia?
Increase in the number of cells
Which signals cause a cell to undergo cell division?
Growth factors
Which enzyme is bound to some growth receptors?
Tyrosine kinase
Which protein, other than tyrosine kinase, is bound to some growth receptors?
G-protein
Which pathway involves tyrosine kinase, RAS and RAF?
MAPK/ERK pathway
What are the four stages of the cell cycle, and what happens in each stage?
G1 - protein synthesis
S - DNA replication
G2 - more protein synthesis
M - mitosis
Which enzymes control the progression of the cell cycle?
Cyclin dependent kinases (CDKs)
___ activate CDKs during the cell cycle.
Cyclins
Which protein is activated by CDK4 during G1?
Retinoblastoma (Rb)
What is the protein which controls the main checkpoint in G2?
p53
p53 checks the cell for DNA ___.
errors
If p53 finds a DNA error in a cell, ___ is attempted.
repair
Normally, if DNA repair is unsuccessful, the cell is instructed to undergo ___.
apoptosis
Which tissue undergoes hyperplasia during pregnancy?
Endometrial lining of the uterus
What process occurs as a compensatory mechanism after tissue loss?
Hyperplasia
Which organ can regenerate through hyperplasia?
Liver
Which organ undergoes pathological hyperplasia as men age?
Prostate
Which structures undergo hyperplasia as a response to infection?
Lymph nodes
Hyperplasia is (reversible / irreversible).
reversible
What is worrying about hyperplastic tissue?
It’s at high risk of developing cancer
Hypertrophy is usually a response to which type of distress?
Mechanical
Hypertrophy (increases / reduces) the blood demand of cardiac tissue.
It also makes cardiac muscle (more / less) functional.
increases blood demand
renders tissue less functional
What is the end result of cardiac hypertrophy?
Heart failure
What is atrophy?
Reduction in cell size
What causes pathological atrophy?
Decreased workload
