ADAPTATION AND CELL INJURY

Question 1

Defined as an alteration in cell structure or functioning resulting from some stress that exceeds the ability of the cell to compensate through normal physiologic adaptive mechanisms.

Answer 1

Injury

Question 2

If injured cells recover their normal functions when the stress is removed, the injury is said to be ______.

Answer 2

reversible

Question 3

If the injury is severe enough, however, a “point of no return” is reached and the cell suffers ______ injury and dies. Two patterns of cell death are observed: necrosis and apoptosis

Answer 3

irreversible

Question 4

How a cell responds to stress depends on ?

Answer 4

Severity and duration of exposure to stressor (dose intensity)

Question 5

Cell injury is associated with damage to the structural and functional molecules of the cell. Although any biologically important molecule in a cell can be the target of injury producing stress, four biochemical systems are particularly vulnerable: (Name these)

Answer 5

1.The cell membrane
2. Energy metabolism
3. Protein synthesis
4. Genes

Question 6

Name this pathological stimuli:

• Depriving tissues of oxygen is one of the more common mechanisms for cellular injury
• Can result from interrupted blood supply (ischemia), inadequate oxygenation of blood due to pulmonary disease or hypoventilation, inability of the heart to adequately pump blood (heart failure), or impaired oxygen carrying capacity of the blood (anemia, carbon monoxide poisoning, etc.).

Answer 6

Hypoxia

Question 7

Name this pathological stimuli:

• A very large number of drugs and environmental _____ _____ are capable of causing cell injury.
• The list includes inorganic compounds, ions, and organic molecules - including byproducts of normal metabolism and toxins synthesized by microorganisms.

Answer 7

Chemical agents

Question 8

Name this pathological stimuli:

• Many forms of physical injury can be harmful to cells and tissues. Common examples include: (1) Mechanical injury (crush injury, fractures, lacerations, hemorrhage). (2) Extremes of heat or cold (burns, heat stroke, heat exhaustion, frostbite, hypothermia). (3) Ionizing or non-ionizing radiation - (x-rays, radioactive elements, ultraviolet radiation). (4) Electric shock. (5) Sudden changes in atmospheric pressure (blast injury, decompression injury in divers). (6) Noise trauma.

Answer 8

Physical agents

Question 9

Name this pathological stimuli:

• This very common category of cell injury results from the parasitization of the body by pathogenic viruses, bacteria, fungi, protozoa, or helminths.
• Pathogenic organisms produce disease by either: (1) replicating inside host cells and disrupting the structural integrity of the cell (direct cytopathic effect - e.g., herpes virus), (2) producing a toxin that is harmful to host cells (e.g., clostridia and diphtheria), or by (3) triggering an inflammatory or immune response that inadvertently injures host cells caught in the “cross fire” between the immune system and invading microorganism (e.g., rheumatic fever, tuberculosis).

Answer 9

Infection

Question 10

Name this pathological stimuli:

• Exaggerated _____ _____ (anaphylaxis, allergy), or the inappropriate targeting of the body’s own cells by the immune system (autoimmunity) can result in acute or chronic inflammation and cell injury. Abnormal suppression of the immune system can increase vulnerability to microbial invasion.

Answer 10

Immune reactions

Question 11

Name this pathological stimuli:

• Deficiencies or excesses in normal cellular substrates (e.g., calories, proteins, carbohydrates, minerals, vitamins) can produce problems such as obesity, malnutrition, scurvy, iron deficiency anemia, etc.

Answer 11

Nutritional imbalance

Question 12

Name this pathologic stimuli:

• Inherited or acquired mutations in important genes can alter the synthesis of crucial cellular proteins leading to developmental defects, or abnormal metabolic functioning.
• Acquired mutations to somatic cells during life can affect cell differentiation and replication leading to diseases such as cancer.

Answer 12

Genetic derangements

Question 13

Name this adaptive structural changes:

A decrease in individual cell size due to lower rates of metabolism and decreased protein synthesis.

Answer 13

Atrophy

*** Atrophic cells have less structural proteins, fewer mitochondria, and less endoplasmic reticulum. Although atrophic cells have reduced functions, they are not dead. The reduced metabolic activity of atrophic cells makes them less vulnerable to injury. When a sufficient number of cells become atrophic, the whole tissue or organ diminishes in size. Occasionally the numbers of cells in atrophic tissues may also decrease. This is sometimes referred to as involution.

Question 14

Name this adaptive structural changes:

Increase in tissue mass due to an increased rate of cell division and cellular proliferation. A _______ organ is increased in size because it has more cells.

Answer 14

Hyperplasia

Question 15

Name this adaptive structural changes:

A reversible change in cell structure from one fully differentiated form to another in response to a noxious stimulus. ________ represents an attempt by tissue to replace a susceptible cell type with a more resistant one.

Answer 15

Metaplasia

Question 16

Name this adaptive structural changes:

Disordered cellular morphology, organization, and function. Unlike atrophy, hypertrophy, and hyperplasia which may be physiologic adaptations as well as manifestations of disease, _______ (and probably metaplasia) is always associated with a pathologic process.

Answer 16

Dysplasia

Question 17

A common feature of almost all cell injuries. A form of reversible injury associated with the abnormal influx of sodium and water into the cell.

Answer 17

Cell swelling

Question 18

Another way cells can adapt to injury that disrupts metabolic pathways is to accumulate and store various substances in the cytoplasm. _______ _______ may be substrates of biosynthetic processes or normal cellular constituents such as lipids, proteins, or carbohydrates - or pigments such as melanin and bilirubin.

Answer 18

Intracellular accumulations

Question 19

Refers to accumulation of triglycerides. Most often seen in liver, commonly caused by alcohol abuse appears as clear vacuoles within parenchymal cells

Answer 19

Fatty change

Question 20

May be found in overloaded phagocytes these cells (often smooth muscle or macrophages) are called foam cells commonly found in atherosclerosis, give the characteristic yellow color

Answer 20

Cholesterol and cholesteryl esters

Question 21

Found in hepatocytes of alcoholics.
Glycogen is found in certain abnormalities of metabolism, such as storage disease or diabetes.

Answer 21

Mallory body or alcoholic hyaline

Question 22

Injury and cell death can cause the release of intracellular phosphate ions and fatty acids into the extracellular environment. These compounds react with calcium ions forming insoluble calcium salts which are precipitated in tissues. Name this phenomenon.

Answer 22

Calcification

Question 23

-Injury to cell membranes can also be associated with the leakage of normal intracellular enzymes into extracellular fluids. Elevated plasma levels of these enzymes are often used as indirect laboratory markers for cell injury. A common example is myocardial infarction which is associated with elevations of serum creatine kinase (CK) and cardiac troponins. Hepatobiliary disease is frequently accompanied by elevations of the enzymes AST, ALT, and alkaline phosphatase. Name this phenomenon.

Answer 23

Enzyme leakage

Question 24

The structural changes that accompany necrosis result from what two processes?

Answer 24

1. Enzymatic digestion of the cell by its own hydrolytic lysosomal enzymes (sometimes called liquefaction necrosis)
2. Denaturation and precipitation of cellular proteins (coagulation necrosis)

Question 25

Refers to the deposition of lipids in the cytoplasm of adipose tissue cells found among interstitial connective tissue cells throughout the body. If the amount of stromal fat is excessive, "obesity" is used as a descriptive term. This is not considered to be cellular injury.

Answer 25

Stromal fatty infiltration

Question 26

Refers to an abnormal accumulation of fat within parenchymal cells. It occurs most frequently in those cells involved in, or dependent on, fat metabolism (cells of the liver, heart and kidneys).

Answer 26

Fatty change

Question 27

Refers to an increase in cell size due to increased intracellular accumulation of water. It is the earliest or first manifestation viewed with the light microscope in almost all sick or ill cells.

Answer 27

Cellular swelling

Question 28

What happens to plasma membrane under the influence of sick or ill cell?

Answer 28

* The plasma membrane is involved (primarily or secondarily) in virtually all forms of injury. * Very early in the cell's response to injury, no ultrastructural alterations are observed; however, biochemical studies disclose increased cell membrane permeability which is reflected by increased intracellular accumulation of sodium, water and calcium ions, as well as by a leakage of potassium, enzymes and cofactors. * Later in the cell's response to injury, distortion of microvilli, blebs, and vesicles occur in the membrane. * Still later, breaks are seen in both the plasma membrane and the membranes enclosing the organelles.

Question 29

What happens to mitochondria under the influence of sick or ill cell?

Answer 29

* The mitochondria are almost always altered when the cell is injured. * Alterations occur rapidly after hypoxic injury but are delayed in many forms of chemical injury (the following refers to hypoxic injury). * The earliest response to hypoxic injury is condensation of the mitochondrial matrical proteins (associated with a loss of ATP). * However, this is quickly followed by swelling of mitochondria (related to increased cell membrane permeability). With progressive injury, the mitochondrial matrix becomes translucent. * Flocculation of mitochondrial matrical proteins correlates with the onset of cell death; this is the earliest absolute sign of cell death.

Question 30

What happens to endoplasmic reticulum under the influence of sick or ill cell?

Answer 30

* The endoplasmic reticulum responds very early when the cell is injured; it swells due to an intake of water. * This swelling is followed by detachment of ribosomes and desegregation of polysomes resulting in decreased synthesis of protein. * Subsequently, progressive fragmentation of the endoplasmic reticulum occurs. * Swelling of the endoplasmic reticulum is usually the first manifestation of cell injury.

Question 31

Nucleus is unaffected in the sick or ill cell. True or False?

Answer 31

True

Question 32

There is a time lapse of ______ hours between the onset of cell death and the non-controversial recognition that the cell is dead by light microscopy.

Answer 32

6 to 12

Question 33

Describe the light microscopic and gross changes in dead/necrotic cells.

Answer 33

* Nuclear changes are the "hallmark" of cellular necrosis (cell death). * The nuclear changes appear in the form of one of three patterns (pyknosis, karyorrhexis and karyolysis). * The cytoplasm of a necrotic cell becomes transformed into an acidophilic, granular opaque mass. * After a cell dies and undergoes the early changes of cell death, immediate dissolution may not occur. * Instead, one of three distinctive patterns may ensue, depending on the balance between progressive proteolysis, coagulation of proteins and calcification. * Thus, the necrotic cell may undergo coagulative necrosis, liquefactive necrosis or, in special circumstances, caseous, gangrenous or fat necrosis.

Question 34

Refers to a nucleus that progressively shrinks and becomes transformed into a small, dense, wrinkled mass of tightly packed chromatin.

Answer 34

Pyknosis

Question 35

Refers to a nucleus that breaks or fragments into many clumps or pieces.

Answer 35

Karyorrhexis

Question 36

Refers to a nucleus in which there is progressive dissolution of the chromatin and eventual disappearance of the nucleus.

Answer 36

Karyolysis