Apoptosis, Cell Adaptation Flashcards
What are three main reasons for apoptosis?
- Cell turnover: mucosa, skin, etc. or due to loss of growth factor
- Embryogenesis: development
- Immune function
What are some diseases that cause excessive apoptosis?
- AIDS
- Ischemia
- Neurodegenerative diseases
- Myelodysplasia
- Toxin induced liver injury
What are some diseases that inhibit apoptosis?
- Cancer: breast, prostate, and ovary cancer
- Autoimmune disease
- Viral diseases: HSV, poxvirus, and adenovirus
What is the general overview of apoptosis?
Chromatin condensation -> cell shrinkage -> membrane blebs and sheds apoptotic bodies to be phagocytosed
What are the two methods of inducing apoptosis?
Receptor mediated (extrinsic)
Mitochondrial pathway (intrinsic)
What could cause the mitochondrial pathway for apoptosis to start?
- Growth factor withdrawal
- DNA damage
- Protein misfolding
What intracellular molecules do both the intrinsic and extrinsic pathways need to activate for apoptosis to occur?
Initiator caspases
Apoptosis or necrosis causes the cell to shrink?
Apoptosis
Apoptosis or necrosis causes the cell to spill all of its contents?
Necrosis
Apoptosis or necrosis normally effects multiple cells.
Necrosis
Apoptosis or necrosis normally involves chromatin condensation?
Apoptosis
Apoptosis or necrosis causes inflammation?
Necrosis
What are some various cell adaptations that can take place in response to chronic stress?
- Size change
- Cell number change
- Change in cell differentiation
- Abnormal intracellular contents
What is hypertrophy vs hyperplasia?
Hypertrophy: grow in size
Hyperplasia: grow in number
What are some etiologies of atrophy?
- Decreased workload
- Loss of innervation
- Decreased blood supply
- Poor nutrition
- Decreased hormone stimulation
- Aging
- Local pressure
What would happen to the muscles of the face if innervation was lost?
Atrophy
What would happen to the kidney cells if blood supply was lost?
Atrophy
What happens to breast tissue after estrogen stimulation is lost?
Atrophy
What happens to the muscle cells as someone consistently works out over a long period of time?
Hypertrophy
T/F: Hypertrophy can be done via increased functional load and hormonal stimulation.
TRUE
How does the uterus prepare to push out a baby?
Hypertrophy of smooth muscle during pregnancy
How can hyperplasia be stimulated in the body?
- Hormonal
2. Chronic irritation (calice)
Smoking can cause ____________ of the normal columnar epithelia into squamous epithelia in the bronchus.
Metaplasia
What can happen in the esophagus as a response to chronic GERD?
Metaplasia from stratified squamous -> mucous epithelium.
Can be a set up for cancer
What are some mechanisms for intracellular accumulations?
- Abnormal metabolism (fatty liver)
- Defect in protein folding/transport (Alzheimer’s)
- Lack of enzyme (glycogen storage disease)
- Ingestion of indigestible materials (pigments)
What is an example of a signal activating the extrinsic apoptotic pathway?
Fas ligand binding to TNF receptor
What is the role of the Bcl-2 family in the apoptotic pathway?
Controls mitochondria permeability for the intrinsic pathway.
Bcl-2, bcl-x inhibit apoptosis
Bax, bak stimulate apoptosis
What cellular molecules promote apoptosis?
- Bax, Bak (pre-mitochondria)
- Cytochrome c (post-mitochondria)
- Caspases - breaks down cell
