chapter 4c,d Flashcards
What is apoptosis?
Natural and controlled/regulated death of cells within the body.
What triggers apoptosis in a cell?
Signals received when a cell malfunctions, is damaged, or becomes unnecessary.
What are the two pathways of apoptosis?
- Intrinsic pathway (mitochondrial pathway)
- Extrinsic pathway (death receptor pathway)
What initiates the intrinsic pathway of apoptosis?
Detection of internal cellular damage.
What initiates the extrinsic pathway of apoptosis?
Reception of extracellular death signalling molecules.
What is the first stage of apoptosis?
Digestion of cell contents.
What happens during the cell shrinking stage of apoptosis?
The cell and nucleus shrink as intracellular material is broken down.
What is membrane blebbing?
Weakening of the cell’s structural integrity as the cytoskeleton is digested.
What are apoptotic bodies?
Membrane-enclosed vesicles containing broken down intracellular material.
What role do phagocytes play after apoptosis?
They engulf and digest free-floating apoptotic bodies by phagocytosis.
What is necrosis?
Unregulated death of cells initiated by significant damage.
What characterizes necrosis?
Cells swell, burst, and release contents into the surrounding environment.
How can apoptosis-related malfunctions affect cell behavior?
They can lead to deviant (abnormal) cell production.
What happens when the rate of apoptosis decreases excessively?
Cell growth can increase exponentially, resulting in the formation of tumors.
Define a benign tumor.
A mass of abnormal cells that lacks the ability to spread throughout other tissues and organs.
Define a malignant tumor.
Abnormal cells with the ability to invade nearby tissue and migrate to other parts of the body.
What are the characteristics of benign tumors?
- Non-cancerous
- Slow growing
- Not typically life-threatening
- Do not invade nearby tissue
- Do not spread to other parts of the body
What are the characteristics of malignant tumors?
- Cancerous
- Fast-growing
- Can be life-threatening
- Able to invade nearby tissue
- Do spread (metastasize) to other parts of the body
What is a stem cell?
Undifferentiated cells with the capability of differentiating into specialized cells.
What is differentiation?
The process by which stem cells become specialized.
What are totipotent stem cells?
Stem cells that can differentiate into any cell type.
What are pluripotent stem cells?
Stem cells that can differentiate into multiple cell types.
What are multipotent stem cells?
Stem cells that can differentiate into a limited number of specialized cell types belonging to a specific tissue or organ.
Give an example of a totipotent stem cell.
Zygote.
