Apoptosis And Necrosis

Question 1

Apoptosis

Answer 1

Programmed cell death

Question 2

Necrosis

Answer 2

A series of morphological changes during cell death after lethal damage
-staged cell death due to unintended damage

Question 3

Physiological apoptosis

Answer 3

1. During embryonic development

2. During immune system development

Question 4

Pathological apoptosis

Answer 4

1. Triggered by immune system cells in response to cell infection
2. Self induced due to defective function, developing cytotoxicity

Question 5

Can necrosis be physiological and pathological?

Answer 5

No, it’s always pathological

Question 6

Necrosis involves

Answer 6

• disruption of the metabolic process
• cellular component desaturation
• loss of membrane integrity and release of cellular components to surroundings

Question 7

Apoptosis during embryonic development

Answer 7

Phylogenic organism development programs use programmed cell death as a means of removing unwanted cells: tissue between fingers and toes

Question 8

Apoptosis during immune system development

Answer 8

• T cells are tested against ‘self antigens’ and if they recognize and bind self antigens, they undergo apoptosis to remove their own lineage
• if they did not ‘self-destruct’ they would kill normal cells upon activation leading to autoimmune disorders

Question 9

Apoptosis triggered by immune system cells

Answer 9

When a harmful/compromised cell is identified, innate immune cells trigger that cell’s apoptosis program

Question 10

After the cells innate immune cells trigger apoptosis what happens

Answer 10

• infected cells display ‘non-self antigens’
• transformed ‘cancer’ cells display unusual attributes
• damaged cells or cells developing characteristics of damage

Question 11

Self induced apoptosis

Answer 11

-cells that surpass specific thresholds acceptable for survival can self induce apoptotic programming. This may include slight metabolic defects or the accumulation of toxic substances such as aggregating proteins

Question 12

Intrinsic apoptotic pathways

Answer 12

Initiated by interior signaling die to irreparable, irreversible DNA damage

Question 13

What can cause a cell to undergo intrinsic apoptotic pathway?

Answer 13

• severe stress
• pro-apoptotic proteins from the nucleolus and mitochondria activate the CASPASE CASCADE
• caspases destroy proteins and other molecules with in the cell
• cell begins to bleb into vesicles
• phagocytes cells engulf and digest the ‘blebbed’ vesicles

Question 14

Extrinsic apoptotic pathway

Answer 14

Initiated by exterior signals due to indications of damage or infection

Question 15

What could cause extrinsic apoptotic pathway?

Answer 15

• T cell or TNFa induced activation of death domain proteins
• activation of capsase cascade
• capsases destroy proteins and other molecules with in the cell
• cell begins to bleb into vesicles
• phagocytes cells engulf and digest the ‘blebbed’ vesicle

Question 16

AIF-apoptosis inducing factor

Answer 16

A capsase independent form of apoptosis

Question 17

What is AIF initiated by?

Answer 17

Damage to the mitochondrion and release of material from the mitochondrial inner membrane space to the cytosol

Question 18

AIF leaving the mitochondrial

Answer 18

Passes through the cytosol to the nucleus where it causes chromosome condensation

Question 19

What happens once the chromosomes are condensed in AIF?

Answer 19

The DNA is chopped up

Question 20

The over all effect of AIF

Answer 20

Results in the compete depletion of energy stores in the cell, no production of new proteins or metabolites, cell ‘blebbing’, and a quiescent cell death similar to apoptosis utilizing caspases

Question 21

What is the difference between intrinsic/extrinsic and AIF

Answer 21

Extrinsic and intrinsic involve capsases

Question 22

Which forms of apoptosis is considered quiescent?

Answer 22

All of them

Question 23

What could be some unintended damage that would cause staged cell death (necrosis)?

Answer 23

• trauma
• infection
• radiation
• toxins
• ischemia
• heat/cold

Usually environmental in nature

Question 24

What does necrosis involve?

Answer 24

• disruption of the metabolic process
• cellular component denaturation
• loss of membrane integrity and release of cellular components

Question 25

Disruption of the metabolic process in necrosis

Answer 25

• Loss of TCA and ETS
• glycolysis drives formation of lactic acid.
• rely totally on glycolysis, build up of lactic acid

Question 26

Cellular component denaturation in necrosis

Answer 26

Increasing lactic acid drives pH down denaturing proteins

Question 27

Loss of membrane integrity and release of cellular components In necrosis

Answer 27

-complete loss of all cellular function results in the release of many cellular components that will cause problems in cells/tissues surrounding it

Question 28

Overview of apoptosis

Answer 28

Form of cell death that is regulated and results in the formation of ‘blebbed’ vesicles containing the partially digested contents of the cell. This is considered a quiescent death and does not negatively impact the surrounding cells

Question 29

Necrosis overview

Answer 29

Results in the complete breakdown of cellular organization. Lysosomal enzymes are released to conduct autolysis and heterolysis when the cell ruptures. Enzymes and materials released cause damage to surrounding interstitial and cells, perpetuating the damage. Opportunistic microbes may benefit. Inflammatory response occurs
-after extensive clean up, tissue repair and scar tissue forming fibroblasts must be activated