Chapter 4: Cell Injury, Aging, and Death

ANS: D Free radicals are formed when high-energy electrons partially reduce oxygen in reperfusion injury. Reperfusion injury usually causes more cell damage than the original hypoxia. It results from calcium overload in the cells. Reperfusion injury results from hypoxic injury, rather than from nutritional injury.

10. Reperfusion injury to cells a. results in very little cellular damage. b. results from calcium deficiency in cells. c. occurs following nutritional injury. d. involves formation of free radicals.

ANS: C Hypothermia causes increased blood viscosity, which can result in ischemic injury. Initial vasoconstriction causes ischemic injury. Rebound vasodilation leads to intense swelling which damages peripheral nerves. Crystallization of cellular components leads to rupture of these components.

11. Extreme cold injures cells by all the following except a. ischemic injury from vasoconstriction. b. peripheral nerve damage from rebound vasodilation. c. decreased blood viscosity. d. crystallization of cellular components.

ANS: B Cellular DNA is particularly susceptible to damage from radiation via breakage of the bonds holding the linear DNA together. Cell membranes, RNA, and ribosomes are not the most susceptible to radiation injury.

12. The cellular component that is most susceptible to radiation injury is the a. membrane. b. DNA. c. RNA. d. ribosomes

ANS: B Carbon monoxide binds tightly to hemoglobin preventing the red blood cell from carrying adequate oxygen, leading to hypoxic injury. Other chemicals such as carbon tetrachloride promote free radicals, which injure cells and destroy cellular membranes. Crystallization of cellular organelles is caused by hypothermia.

14. Carbon monoxide injures cells by a. destruction of cellular membranes. b. reducing oxygen level on hemoglobin. c. promotion of free radicals. d. crystallization of cellular organelles.

ANS: C Deficient cellular uptake by one cell type may contribute to excess nutrient delivery to other cell types such as in diabetes mellitus. Most of these essential nutrients must be obtained from external sources, because the cell is unable to manufacture them. Obesity involves an excess of caloric intake. The BMI is a measure for obesity, but does not indicate if a nutritional imbalance is prese

15. Of the statements below, the accurate statement regarding nutrition and cellular health is a. the body can generally produce elements essential for nutritional balance. b. obese individuals are generally nutritionally healthy. c. deficient cellular uptake by one cell type may contribute to excess nutrient delivery to other cell types. d. a normal BMI indicates nutritional health.

ANS: A, B, C, E Bacteria function in multiple ways to cause cell injury, including producing exotoxins that interfere with cellular function, producing endotoxins that cause fever and circulatory shock when the bacteria are lysed, producing enzymes that digest cellular membranes, or evoking an immune response with release of chemicals (e.g., histamines, kinins, lymphokines) that can injure cells. Bacteria do not reproduce inside host cells.

16. Bacteria cause injury to cells by (Select all that apply.) a. producing exotoxins. b. producing endotoxins. c. producing destructive enzymes. d. reproducing inside of host cells altering cellular function. e. evoking an immune reaction.

ANS: A, C, E Viruses are able to enter the host cell and use host metabolic processes to survive and replicate. Viruses do not produce toxins. Viruses do not directly produce free radicals, although these can be produced indirectly by the immune response that folows viral infection. Both viruses and bacteria produce an immune response. REF: Pgs. 67-68

17. Viruses differ from most bacteria in that they (Select all that apply.) a. enter the host cell. b. directly produce free radicals. c. use the host's metabolic processes to survive and replicate. d. do not induce an immune response. e. do not produce toxins.

ANS: A, B, C, E Exotoxins produced by bacteria interfere with cellular functions. Endotoxins are a component of some bacteria; when the bacteria are lyses, endotoxins are released, causing fever and even circulatory shock. Virally infected cells may trigger their own destruction. Enzymes from white blood cells can harm cells in the area of inflammation. Infectious injury promotes inflammation; inflammation can cause more damage than the infecting agent.

18. Infectious injury often results from (Select all that apply.) a. exotoxins. b. endotoxins. c. self-destruction of cells. d. anti-inflammatory reactions. e. enzymes from white blood cells.

ANS: A Necrosis refers to death of cells/tissue and is not reversible. Metaplasia refers to the replacement of one differentiated cell type with another from persistent injury and is reversible when the injury stops. Atrophy occurs due to lack of use of an organ and is reversible. Hyperplasia is an increase in the number of cells from increased physiologic demands or hormonal stimulation and is reversible.

3. All these cellular responses are potentially reversible except a. necrosis. b. metaplasia. c. atrophy. d. hyperplasia.

ANS: A Metaplasia is the replacement of one differentiated cell type with another secondary to persistent damage. Dysplasia transforms cells to preneoplastic lesions, which may become malignant. Metaplasia is reversible when the damage is stopped. Disorganization of cells into various sizes, shapes, and arrangements occurs in dysplasia.

6. Metaplasia is a. the replacement of one differentiated cell type with another. b. the transformation of a cell type to malignancy. c. an irreversible cellular adaptation. d. the disorganization of cells into various sizes, shapes, and arrangements.

ANS: B Dysplastic cells have the potential to become cancerous and are therefore referred to as preneoplastic. Anaplasia, metaplasia, and hyperplasia are not considered preneoplastic.

7. The cellular change that is considered preneoplastic is a. anaplasia. b. dysplasia. c. metaplasia. d. hyperplasia.

ANS: B Somatic death refers to death of an entire organism. Somatic death is not simply death of one body organ. Somatic death involves death of all cells in the body. Brain death refers to death of the brain only, but organ systems can remain living withmechanical assistance.

8. Somatic death refers to death a. of a body organ. b. of the entire organism. c. of nerve cells. d. secondary to brain damage.

ANS: D Coagulative necrosis results from interrupted blood supply leading to ischemic cell injury. Liquefactive necrosis results from dissolving of dead cells and cyst formation. Fat necrosis is caused by trauma or pancreatitis. Caseous necrosis is caused by lung tissue damage such as that caused by tuberculosis.

9. Coagulative necrosis is caused by a. dissolving of dead cells and cyst formation. b. trauma or pancreatitis. c. lung tissue damage. d. interrupted blood supply.

ANS: B Increased function of an organ such as the heart or skeletal muscle results in organ hypertrophy due to cellular enlargement. Atrophy refers to reduction in size of an organ due to cellular shrinkage. Metaplasia refers to replacement of one differentiated cell type with another. Inflammation results from immune response rather than workload.

An increase in organ size and function due to increased workload is termed a. atrophy. b. hypertrophy. c. metaplasia d. inflammation.

ANS: B Apoptosis results in death of a cell when it is no longer needed. Atrophy refers to reduction in size of an organ due to cellular shrinkage. Proliferation refers to growth of new cells. Mutation refers to alteration in the genetic structure of cellular DNA.

Apoptosis is a process that results in cellular a. atrophy. b. death. c. proliferation. d. mutation.

ANS: C Liquefactive necrosis is produced when brain tissue dies, as it is rich in enzymes and has little connective tissue. Coagulative necrosis occurs from ischemic injury in any tissue. Caseous necrosis occurs in lung tissue damaged by tuberculosis. Fatnecrosis occurs in adipose (fat) tissue.

Necrotic death of brain tissue usually produces _____ necrosis. a. coagulative b. caseous c. liquefactive d. fat

ANS: D Intracellular accumulations result from faulty metabolism of lipids, carbohydrates, glycogen, and proteins. Hydropic swelling results from malfunction of the sodium-potassium pump. Lactate production results from anaerobic glycolytic pathway. Metaplasiaoccurs from persistent cell injury.

The cellular response indicative of injury due to faulty metabolism is a. hydropic swelling. b. lactate production. c. metaplasia. d. intracellular accumulations.

ANS: A All body systems show age-related changes that can be generally described as a decrease in functional reserve; aging leads to inability to adapt to (internal and external) environmental changes. Not all effects of aging are considered disease; some are considered a normal part of aging. Programmed senescence is currently only a theory of aging that states cells have a pre-programmed number of cell divisions before they will die. Senility is an outdated term used to describe the cognitive changes associated with dementia; dementia is a disease and is not a normal part of aging.

The primary effect of aging on all body systems is a. decreased functional reserve. b. diseased function. c. programmed senescence. d. senility.