Answers
define cell necrosis
(Ans-
- irreversible injury
- rapid plasma membrane structure loss
- organelle swelling
- mitochondrial dysfunction
what happens in cell necrosis
(Ans-
- cell membrane is ruptured
- leakage of cell contents
- ATP is lost
- organelles swell
- severe mitochondrial damage
- local inflammation
define apoptosis
(Ans- programmed cell death; not associated with inflammation
list the three mechanisms of apoptosis
(Ans-
1. apoptosis triggered by internal signals: mitochondrial pathway
2. apoptosis triggered by external signals: death receptor pathway
3. apoptosis-inducing factor (AIF)
describe the mitochondrial pathway of apoptosis
(Ans-
- outer membrane of cells have a protein called Bcl-2, which inhibits
apoptosis
,- internal cell damage results in a protein called Bax to go to the surface
and block Bcl-2
- Bax punches holes in the mitochondrial membrane
- cytochrome c leaks out and binds to Apaf-1 (apoptosomes)
- apoptosomes bind to and activate caspase 9
- initiates cascade of caspases
- destruction of structural proteins and degradation of chromosomal DNA
- phagocytosis
describe the death receptor pathway of apoptosis
(Ans-
- FAS and TNF are death receptor proteins on the cell membrane
- Fasl activates FAS and TNF by binding them to a ligand
- activation triggers caspase 8
- initiates cascade of caspases
- phagocytosis
describe apoptosis inducing factor
(Ans-
- cell receives signal that it is time to die
- AIF is released from mitochondria
- AIF migrates to the nucleus and binds to DNA
- triggers destruction of cell death
what are two viruses that "trick" apoptosis?
(Ans-
1. HPV
2. Epstein Barr Virus
list five examples of cell adaptation
(Ans-
1. atrophy
2. metaplasia
3. dysplasia
4. hypertrophy
, 5. hyperplasia
define atrophy in cell adaptation
(Ans- when there is decreased work demand, the cell decreases in size to
work at a more efficient level
define metaplasia in cell adaptation
(Ans- response to chronic irritation in which a cell that is better able to
survive replaces the original cell
define dysplasia in cell adaptation
(Ans- maladaptation; deranged cell growth and differentiation within a
specific tissue; precursor of cancer
define hypertrophy in cell adaptation
(Ans- when there are increased work demands, the cell increases in size
define hyperplasia in cell adaptation
(Ans- an increase in the number of cells in an organ or tissue that is
capable of mitotic division
aging is thought to be the result of:
(Ans-
1. faulty DNA repair mechanisms
2. reduced antioxidants
define intracellular fluid
(Ans- all the fluid within the cells (2/3 of total body water)
define extracellular fluid
(Ans- all the fluid outside of the cells (1/3 of total body water)
what makes up extracellular fluid
(Ans-
1. interstitial fluid (3/4)