Question 1

function of necrosis

Accepted Answer

removes damaged cells from an organism failure to do so may lead to chronic inflammation - necrosis causes acute inflammation to clear cell debris via phagocytosis

Question 2

causes of necrosis

Accepted Answer

usually lack of blood supply, e.g.: ``` injury infection cancer infarction inflammation ```

Question 3

necrosis step-by-step

Accepted Answer

1. result of injurious event 2. initial events are reversible, later ones are not 3. lack of oxygen prevents ATP production 4. cells swell due to influx of water (ATP is required for ion pumps to work) 5. lysosomes rupture: enzymes degrade other organelles and nuclear material haphazardly 6. cellular debris released, triggering inflammation

Question 4

microscopic appearance of necrosis

Accepted Answer

1. nuclear changes = chromatin condenses/shrinks 2. fragmentation of nucleus 3. dissolution of chromatin by DNAse cytoplasmic changes - opacification = protein denaturation and aggregation - complete digestion of cells by enzymes causing cell to liquify biochemical changes: - release of enzymes such as creatine kinase or lactate dehydrogenase release of other proteins such as myoglobin - these biochemical changes are useful in the clinic as ways to measure extent of tissue damage

Question 5

normal vs nectrotic kidney

Accepted Answer

loss of blue stain of nuclei

Question 6

functions of apoptosis

Accepted Answer

selective process for deletion of superfluous, infected or transformed cells ``` involved in: embryogenesis metamorphosis normal tissue turnover endocrine-dependent tissue atrophy variety of pathological conditions ```

Question 7

apoptosis step-by-step

Accepted Answer

1. programmed cell death of one or few cells 2. events are irreversible and energy dependent 3. cells shrink as cytoskeleton is disassembled 4. orderly packaging of organelles and nuclear fragments into membrane bound vesicles 5. new molecules are expressed on vesicle membranes that stimulate phagocytosis without an inflammatory response

Question 8

microscopic appearance of apoptosis 1

Accepted Answer

cytoplasmic changes: 1. shrinkage of cell. organelles packaged into membrane vesicles 2. cell fragmentation. membrane bound vesicles bud off 3. phagocytosis of cell fragments by macrophages and adjacent cells 4. no leakage of cytosolic components

Question 9

morphological features of apoptosis

Accepted Answer

transmission EM = cytoplasm shrinks around nucleus slice through cell scanning EM = 3D,

Question 10

microscopic appearances of apoptosis 2

Accepted Answer

nuclear changes: - nuclear chromatin condenses onto nuclear membrane - DNA cleavage biochemical changes: - expression of charged sugar molecules on outer surface of cell membranes - protein cleavage by protease, caspases

Question 11

DNA fragmentation

Accepted Answer

normal cell = single band apoptosis = smaller band necrosis = entirely non specific, long band

Question 12

describe survival apoptosis

Accepted Answer

``` growth factors cytokines cell-cell and/or matrix contacts disruption of cell-cell and cell matrix contacts ;lack of growth factors dna Damaging ```

Question 13

two types of apoptosis

Accepted Answer

intrinsic or extrinsic

Question 14

describe intrinsic apoptosis

Accepted Answer

``` DNA damage - p53 dependent pathway interruption of cell cycle inhibition of protein synthesis viral infection change in redox state ```

Question 15

describe extrinsic apoptosis

Accepted Answer

withdrawal of survival factors extracellular signals T cell or NK

mechanism of disease 2 Flashcards