8: Necrosis and Apoptosis 1

Question 1

normal cell is in what state? injury is what?

Answer 1

steady state aka homeostasis. injury: any stimulus bringing changes in cell physiology or anatomy

Question 2

injury: reversibility? adaptation?

Answer 2

injury can be reversible or irreversible. irreversible injury results in cell death. adaptation results from changes in a cell due to reversible injury

Question 3

the pathway from steady state to cell death?

Answer 3

injury agent: then get adaptation, then reversible injurious phase, then irreversible injurious phase, then cell death

Question 4

two main events that trigger cells to die?

Answer 4

killed by injurious agents to triggered to commit suicide

Question 5

injurious forces: examples of external and internal factors?

Answer 5

external: physical agents, lack of oxygen, chemical and infections agents. internal: immunologic, genetic, metabolic factors

Question 6

2 types of programmed cell death

Answer 6

apoptosis. non apoptotic PCD.

Question 7

cells that die due to external forces primarily undergo what three types of death?

Answer 7

necrosis. parthanatos (PARP1). autophagy.

Question 8

when does PCD occur?

Answer 8

normally in developing and mature tissue: can be physiologic or pathologic

Question 9

most modes of cell death occur ___, ___, ___

Answer 9

independently, sequentially, and/or simultaneously

Question 10

necrosis is?

Answer 10

dramatic and very rapid form of cell death in which every compartment of the cell disintegrates

Question 11

necrosis: characterized by? which causes 4 things?

Answer 11

dysregulation of ion homeostasis = cell swelling, dilation of mitochondria and ER, formation of vacuoles in cytoplasma, activation of proteases

Question 12

necrosis: activates what proteases

Answer 12

calpains and cathepsins B + D (lyosomal proteases) which will cause cell degradation

Question 13

mitochondrial damage can do what? necrosis?

Answer 13

activate proteases like caspases, and cytochrome c release. not necessary for necrotic cell death

Question 14

during necrosis: what happens in the nucleus? what happens to energy?

Answer 14

chromatin clumps. nuclear membrane disrupted. gene transcription and protein synthesis stops. ATP rapidly depleted (and no energy = ion gradients disrupted)

Question 15

necrosis: what finally happens to the cells? then cells around it?

Answer 15

cells lyse, spill contents into extracellular fluid. contents can damage neighbouring cells, causes inflammatory response

Question 16

can cell undergo only necrosis or apoptosis?

Answer 16

there are very few cell death triggers that are capable of inducing only N or A

Question 17

what determines whether a cell undergoes A or N

Answer 17

the intensity and duration of death-inducing stimulus. severe/sustained = N. less severe/transient = apoptosis.

Question 18

4 types of necrosis

Answer 18

coagulative. liquefactive. caseous. fat.

Question 19

most common form of necrosis = ? occurs where? results from?

Answer 19

coagulative necrosis. occurs in solid internal organs like heart, kidney, adrenal tissue. results from sudden and severe ischemia

Question 20

coagulative necrosis: what happens (2)? what does it look like (2)? finally what happens?

Answer 20

inactivation of hydrolytic enzymes. proteins are denatured. only outline of cells can be seen. boiled meat appearance. eventually, macrophages phagocytose dead tissue, area is replaced with collagenous tissue.

Question 21

liquefactive necrosis: characterized by? what does it look like?

Answer 21

dissolution of tissue: necrotic area is soft and fluid filled, no cell architecture remains

Question 22

liquefactive necrosis: what happens (cellularly)? results from? occurs during?

Answer 22

infiltration of neutrofils. results from enzymatic degradation of tissue. brain ischemia

Question 23

caseous necrosis: what? appearance? when does it occur?

Answer 23

a form of coagulative necrosis, with limited liquefaction. necrotic tissue has appearance of cheese. tuberculosis.

Question 24

fat necrosis: due to? is a type of?

Answer 24

action of enzymes, followed by formation of complexes with calcium. is a type of liquefactive necrosis, specialized to fat.

Question 25

fat necrosis: what do you see? when does it happen (ex)?

Answer 25

focal outlines of necrotic fat cells, surrounded by inflammation. ex: pancreatitis.