Apoptosis

Question 1

Necrosis

Answer 1

Cell death by acute injury

• Mechanical damage
• Exposure to toxic chemicals
• Lytic viral infection

Question 2

Apoptosis

Answer 2

Cell death by suicide (Programmed Cell Death)

	- Internal signals
	- External signals - Collapse of cell - Protein degradation  - DNA fragmentation followed by  - Rapid engulfment of cell corpses by neighboring cells and phagocytes

Apoptosis plays a major role from embryonic development to senescence

Question 3

Apoptosis-Examples

Answer 3

• The resorption of the tadpole tail during metamorphosis-Thyroid hormone induces these morphogenetic events
• The formation of the fingers and toes of the fetus
• The formation of the proper connections between neurons in the brain
• Cells with DNA damage
• Cancerous cells

Question 4

Apoptosis in organ size

Answer 4

Rate of cell division
Rate of cell growth
Rate of cell death

Question 5

Thymus

Answer 5

Thymus (where T lymhocytes develop) have the most activity during fetal development and shortly after birth and after that the thymus starts to shrink and this occurs via apoptosis. By puberty, there is almost no thymus at all.
Also in the mammary gland, it will produce milk during birth and then many cells in the gland will be removed through apoptosis when it’s not longer needed.

Question 6

Self-reactive (apoptosis) Preventing autoimmune reactions

Answer 6

Immune tolerance (good thing): initially, the B and T cells will attack all the antigens including our own body antigens but these are removed through apoptosis. 
Preventing autoimmune reactions