04 - Cell Injury and Repair/Cellular Death

Question 1

Describe and discuss the general causes of cellular injury. (Mnemonic)

Answer 1

Adaptation to stress is not sufficient.
“Please Give Our Cells No Irreversible Injury”
Physical: Electricity, radiation, barotrauma, mechanical stress, burns, excessive cold.
Genetic: DNA alteration that is either inherited or acquired.
Oxygenation: Hypoxia, anoxia (depletion of O2), too much O2.
Chemical: Drugs and toxins can disrupt biochemical cell function or physical cell structure.
Nutritional: Deficiency or excess in vitamins, minerals, or proteins.
Infectious: By an organism, molecular components of an organism (toxins), immune response of organism.
Immunologic: Deficient or exuberant immune response. Inability to distinguish self from non-self (autoimmune).

Question 2

Distinguish between reversible cell injury and irreversible cell injury.

Answer 2

Reversible: Leading to some level of remaining function.
Irreversible: Resulting in cell death.

Question 3

Give examples of cellular injury related to free radicals.

Answer 3

Free radicals are unstable, reactive oxygen species that have single unpaired electrons in the outer orbit. Free radicals can react with lipids (in the plasma membrane and other organelle membranes), modify proteins (reacting with amino acid side chains, promote protein-protein cross linkages, cause oxidation of protein backbones, damage active sites, disrupt conformation or structural proteins, enhance proteasomal degradation), and cause lesions in DNA (single and double strand breaks, DNA cross linking, formation of adducts, can cause cell aging and malignant transformation).

Question 4

Define hypoxia

Answer 4

Less than normal amount of oxygen reaching cells.

Question 5

Define hypoxemia

Answer 5

Less than normal amount of oxygen in blood.

Question 6

Define ischemia

Answer 6

Diminished blood supply to cell or tissue.

Question 7

Define anoxia

Answer 7

Complete deprivation of oxygen due to no blood supply to tissue; leads to infarct.

Question 8

Define induction (of cell injury)

Answer 8

Plasma membrane loses permeability. Sodium and water come into cell, potassium out of cell. Cell swells and calcium enters cell.

Question 9

Define induction (of cell death)

Answer 9

Influx of calcium causes membrane disruption leading to hydrolyzing of proteins and DNA cleavage. Feedback mechanism leads to death.

Question 10

Define effector

Answer 10

Molecules which selectively bind to cells in process of apoptosis to induce degradation by phagocytosis from macrophages.

Question 11

Define degradation

Answer 11

The breakdown of unnecessary or dysfunctional cellular components by lysozymes. In cell death it is an adaptive response to stress which promotes survival of surrounding cells.

Question 12

Define phagocytic

Answer 12

Cells that take particles and substances into self for destruction (eg macrophage, neutrophils).

Question 13

Define degeneration

Answer 13

Mild or reversible structural changes of a cell. Breakdown that leaves some loss of function.

Question 14

Define regeneration

Answer 14

Replacement of lost cells and tissue whose function is so similar to original lost cells that replacements are considered identical. Reproduction of same tissue that was lost.

Question 15

6. Describe the morphologic pattern of single cell necrosis/apoptosis

Answer 15

Nuclear chromatic changes are pyknotic (dark and condensed), the cell shrinks and organelles become compact, cell membrane remains intact for a longer duration (than necrosis) with cell fragmentation. Because preprogrammed, quickly removed by phagocytes/macrophages.

Question 16

Describe the morphological patterns of coagulative necrosis and relate the to common pathogenic mechanisms

Answer 16

Architecture of cell maintained with formation of gelatinous substance in dead tissue (eg infarct, ischemia).

Question 17

Describe the morphological patterns of liquefactive necrosis and relate the to common pathogenic mechanisms

Answer 17

Cell transformed into thick liquid without defined shape (eg bacterial/fungal infections, brain hypoxia).

Question 18

Describe the morphological patterns of caseous necrosis and relate the to common pathogenic mechanisms

Answer 18

Cell becomes amorphous and loses outline. Surrounded by granulomatous inflammatory border (eg tuberculosis, fungal infections).

Question 19

Describe the morphological patterns of fat necrosis and relate the to common pathogenic mechanisms

Answer 19

Necrosis of fat tissue where cell maintains its outline. Surrounded by white, chalky area (eg pancreas and other fatty tissue – breast, abdomen, subcutaneous tissue).

Question 20

Describe the morphological patterns of fibrinoid necrosis and relate the to common pathogenic mechanisms

Answer 20

Cell loses outline and becomes homogenous and pink; resembling fibrin (eg blood vessels of autoimmune pts).

Question 21

Describe the morphological patterns of gummatous necrosis and relate the to common pathogenic mechanisms

Answer 21

Form of granuloma (eg spirochete infections).

Question 22

Describe the morphological patterns of hemorrhagic necrosis and relate the to common pathogenic mechanisms

Answer 22

Caused by blockage of venous drainage of organ or tissue.

Question 23

Describe the signs and symptoms of dry gangrene

Answer 23

Tissue appears black, dry, shriveled with sharp demarcation from viable tissue.

Question 24

Describe the signs and symptoms of wet gangrene

Answer 24

Tissue appears swollen, dark red, liquefied, foul odor present and obscured border from viable tissue.

Question 25

Describe the signs and symptoms of fat saponification

Answer 25

White, chalky areas seen within fat indicating fat necrosis.

Question 26

Describe the signs and symptoms of loss of function (regarding cell death)

Answer 26

Cell death affecting tissue function.

Question 27

Define atrophy in regards to cellular adaptation to injury in tissues

Answer 27

Decrease in size or number of cells.

Question 28

Define hypertrophy in regards to cellular adaptation to injury in tissues

Answer 28

Enlargement due to an increase in the size of cells.

Question 29

Define hyperplasia in regards to cellular adaptation to injury in tissues

Answer 29

Enlargement due to an increased number of cells.

Question 30

Define metaplasia in regards to cellular adaptation to injury in tissues

Answer 30

Reversible change from one type of fully mature cell to a different type of mature cell not usually found in tissue involved.

Question 31

Define dysplasia in regards to cellular adaptation to injury in tissues

Answer 31

Partially reversible change from a mature cell to a cell with abnormalities in both differentiation and maturation.

Question 32

Define anaplasia in regards to cellular adaptation to injury in tissues

Answer 32

Structural differentiation loss within cell or group of cells.