Neoplasia Flashcards
How many cells are in the human body? How many types? How many die? How many are replaced?
30-40 trillion cells
Over 200+ different cell types
As much 100 billion cells die every day and they are replaced (same number of cells, no net effect)
What is cell division? What is this process called?
One mother cell divides into two daughters cells
Each division is called a cell-cycle
What is neoplasia (tumor)?
New, abnormal, uncontrolled growth of tissue
They do not wait for the signals form the body to for new tissue growth
Ignore the signals to stop dividing (they keep dividing)
Do not differentiate/mature normally
Do not undergo apoptosis/die off to keep the cells numbers constant
What is the difference between benign and malignant tumors?
Benign - not cancer
malignant - cancer
What is adenoma?
Benign tumor derived from glandular cells
ex. breast, lung
What is carcinoma?
Malignant tumor derived from epithelial cells
ex. skin and tissue cells
What is adenocarcinoma?
malignant tumor derived from glandular tissue
ex. prostate, pancreas, mamillary gland, colon
What is sarcoma?
malignant tumor derived from bones or soft tissues
What is lymphoma?
malignant tumor derived from lymphocytes
What is melanoma?
malignant tumor derived from melanocytes
What is leukemia?
malignant tumor of blood-forming tissues
What is blastoma?
malignant tumor derived from precursor cells such as embryonic tissue
What are the four phases of the cell cycle? What occurs at each step? How long are each in dividing cells?
G1, S, G2, M
G1 = Cell grows and prepares to divide
S = DNA replication occurs here
G2 = cell continues to grow and prepares for mitosis (synthesize the proteins needed)
M = No more cell growth and begin division
11hrs, 8hrs, 4hrs, 1hr
What is the G0 phase?
Cell has left the cell cycle and has stopped dividing
What is said about the cell cycle in relation to the number of cells?
The total number of cells in the body remain constant
Cells produced = cells that die
True of False: Cells that enter the G0 phase can re-enter the cell cycle
True, after they receive a specific cell signal
What are permanent cells? Provide an example
Cells that leave the cell cycle that cannot return to the cell cycle
This occurs before the G0/G1 phase
ex) neuron cells - nerve cell damage = no way for the body to replace neurons
What is the G0 phase?
Cell has left the cell cycle and has stopped dividing
Where are the checkpoints for cell division located? What occurs if the cell detects that something is wrong?
G1 checkpoint: DNA synth
G2 checkpoint: prep for mitosis
- Apoptosis occurs if something goes wrong
What occurs in the restriction point (R)?
Cell commits to the cycle for division
The restriction point is 2-3 hors before onset of DNA synthesis
What are the four steps of mitosis?
Prophase - condensation of chromatin and disappearance of the nucleus
Metaphase - xsomes align on the metaphase plate + formation of the mitotic spindle
Anaphase - somes split and move to opposite poles of the cell
Telophase and cytokinesis - Spindle disappears, nucleus reforms and mother cell divides in to two daughter cells
What occurs at the anaphase checkpoint?
The cell checks if the xsomes are attached on the mitotic spindle
If this is not met, then apoptosis
What are the signals that tell the cells to divide? At what point do cells not require these signals?
Growth factors; beyond the R point
What are the cell cycle checkpoints and what is checked at each?
G1/S - checks for nick in the DNA (block the replication, apoptosis)
G2/S - check the blocked replication fork, ds DNA breaks, defects in the centrosome/mitotic spindle (block replication, apoptosis)
Anaphase - any xsome that is not attached to the spindle