7.1 Cellular adaptations (cell mechanisms, GF's, cell cycle, cell population characteristics) Flashcards
5 types of cell adaptation are ?
- regeneration
- hyperplasia
- hypertrophy
- atrophy
- metaplasia
pathology is ?
body’s reaction to injuries
size of cell population depends on rate of …?
- cell proliferation
- cell differentiation
- cell death by apoptosis
Increased numbers of cells are seen with …. or ….?
- increased proliferation
- decreased cell death
which conditions does proliferation occur in ?
physiological and pathological conditions
what regulates normal cell proliferation ?
proto-oncogenes
what kind of signals is cell proliferation largely controlled by ?
- soluble
- contact dependent
Cell proliferation is largely controlled by ….1….(soluble or contact dependent) from the ..2… which either ….3…. or ..4…. cell proliferation.
- signals
- microenvironment
- stimulate
- inhibit
cell to cell signalling can be via… :
- hormones
- local mediators (e.g. growth factors)
- direct cell-cell or cell-stroma contact
3 mechanisms of intercellular signalling in cell growth ?
- autocrine
- paracrine
- endocrine
Autocrine mechanism includes what cells ?
same secreting and responding cell
paracrine mechanism includes what cells?
secreting cell and responding cell are different, but co-located (same organ, eg gut)
endocrine mechanism includes what ?
1. endocrine organs synthesise…
2. conveyed through….
3. from site of synthesis the target organ is ….
- hormones
- blood stream
- distant
signalling biochemistry is ….1… but final outcomes are …2..
- complex
- limited
Cells surviving means cell resist …?
apoptosis
when cells divide they enter …?
cell cycle
when cells differentiate what do they take on ?
specialised form and function
when cells die what do they under go ?
apoptosis
Apoptosis:
1. cell death is …
2. physiological / pathological
3. cell …. and ….
4. signals ?
5. no …. reaction
- programmed
- physiological
- collapses, disappears
- internal & external
- inflammatory
Necrosis
1. cell death - gross ….
2. …. reaction
3. 5 examples of external agents involved ?
- tissue death
- inflammatory
- ischaemia, toxin, trauma, infection, heat/cold
Growth factors are local mediators involved in ?
cell proliferation
growth factors stimulate cell proliferation but may also affect cell otherwise how ?
- locomotion
- contractility
- differentiation
- angiogenesis
growth factors:
1. coded by ?
2. act on the cell surface as ?
3. local … ?
- proto-oncogenes
- polypeptides
- hormones
List some growth factors
- epidermal GF
- vascular endothelial GF
- Platelet-derived GF
- Granulocyte colony stimulating factor
Epidermal growth factor is mitogenic for what cells ?
- epithelial cells
- hepatocytes
- fibroblasts
Epidermal growth factor is produced by what ?
- keratinocytes
- macrophages
- inflammatory cells
Epidermal growth factor binds to ?
epidermal growth factor receptor
define vasculogenesis
blood vessel development
define angiogenesis
growth of new blood vessels
2 roles of vascular endothelial growth factor ?
- potent inducer vasculogenesis
- role in angiogenesis in tumours, chronic inflammation and wound healing
Where are platelet-derived growth factors stored and released on ?
- stored in platelet alpha granules
- released on platelet activation
Where are platelet-derived growth factors also produced by ?
- macrophages
- endothelial cells
- smooth muscle cells
- tumour cells
What is caused in smooth muscle cells and monocytes because of platelet-derived growth factors ?
migration and proliferation of fibroblasts
Granulocyte colony stimulating factors are a treatment to stimulate ? include 2 examples of during when
- poorly functioning bone marrow
- during chemotherapy & renal failure
Increased growth of cell occurs by what ?
- shortening of cell cycle
- conversion of quiescent cells to proliferating cells by making them enter the cell cycle
Under the light microscope, only which phase of the cell cycle is distinctive ?
M phase
What are the following phases of the cell cycle ? and what happens ?
1. G1 =
2. S =
3. G2 =
4. M =
- gap 1 , presynthetic, cell grows
- DNA synthesis
- gap 2, premitotic, cell prepares to divide
- mitosis
cell cycle progression is controlled by key … ?
check points
what is checked for G2 checkpoint before enterin M phase ?
- is all DNA replicated ?
- is cell big enough ?
what is checked at G1 phase before enter S phase ?
- is cell big enough ?
- is environment favorable ?
- is DNA damaged ?
What is the most critical checkpoint ? where is it found ?
Restriction point, towards end of G1
What happens to majority of cells that pass the Restriction point ?
they will complete the full cycle so there it’s a point of no return
In cancer cells what kind of checkpoint is the R point ?
most commonly altered checkpoint of the cell cycle
What does the restriction point checkpoint activation delay and trigger ?
- delays cell cycle
- triggers DNA repair mechanisms or apoptosis via p53
what controls the cell cycle ?
cyclins and CDKs
what tightly regulates the progression through the cell cycle and particularly the G1/S transition ?
proteins called cyclins and associated enzymes called CDKs (cyclin-dependent kinases)
When do CDKs (cyclin-dependent kinases) become active ?
binding to and complexing with cyclins
How do activated CDKs drive the cell cycle ?
by phosphorylating proteins that are critical for cell cycle transitions
Give an example of one of the critical proteins regulated by CDKs ?
retinoblastoma susceptibility protein
Many growth factors stimulate production of … ?
cyclins
Activity of cyclin-CDK complexes is tightly regulated by … ?
CDK inhibitors
Some growth factors shut off production of …… inhibitors, the same inhibitors that tightly regulate the activity of cyclin-CDK complexes
CDK inhibitors
What’s the first tumor suppressor gene to be identified ?
RB (retinoblastoma) gene
Retinoblastoma (RB) gene:
1. recessive / dominant gene ?
2. inherited ….. of one gene
- dominant
- absence
How can cell populations be classified according to ?
their ability to enter the cell cycle
In labile cell populations, stem cells divide persistently to … ?
replenish losses
