Cell Injury

Question 1

common causes of cell injury

Answer 1

• hypoxia and anoxia (primary cause)
• free radicals
• toxins
• infection
• immunologic or inflammatory responses
• genetic and metabolic disturbances
• traumatic injury

Question 2

time course of cell injury:

1) homeostasis
2) cell injury
3) reversible changes:
- _____
- _____
- _____
4) cell death
5) irreversible changes:
- _____
- _____
- _____

Answer 2

ATP depletion;
biochemical dysfunction;
early ultrastructural changes: cytoplasmic swelling, vacuolation;

late ultrastructural changes;
early light microscopic changes: pyknosis;
late light microscopic changes: karyorrhexis, karyolysis

Question 3

hypoxic injury and cellular swelling

Answer 3

reduces oxygen delivery to the cell –> inhibits cell’s ability to create adequate ATP –> water moves into cell (bc pumps aren’t working w/o ATP) –> swelling and vacuolation; can be reversible if oxygen delivery is restored

Question 4

ischemic hypoxia

Answer 4

decreased blood flow therefore decreased oxygen (ex: pinched blood vessel); most common

Question 5

ischemic anoxia

Answer 5

no blood flow (ex: blocked blood vessel)

Question 6

anemic hypoxia

Answer 6

red blood cells can’t deliver sufficient oxygen to cells (ex: sickle cell anemia, carbon monoxide poisoning)

Question 7

reactive oxygen species:

____ and _____ generated

Answer 7

internally; externally

Question 8

normal metabolic processes (e.g., mitochondrial electron transport chain) and immune responses generate ___

Answer 8

free radicals

Question 9

free radicals can cause damage to molecules by ____ through oxidation (called oxidative damage)

Answer 9

stealing their electrons

Question 10

a free radical is an atom or group of atoms that have ____, making them extremely ___

Answer 10

1 or more unpaired electrons; reactive

Question 11

___ and ___ forms of reactive oxygen species

Answer 11

radical; non-radical

Question 12

ROS’s are typically neutralized by ____

Answer 12

internally produced anti-oxidants

Question 13

ROS’s are produced in larger amounts with ____

Answer 13

injury and aging (oxidative stress)

Question 14

ROS’s can break ____

Answer 14

covalent bonds in molecules

Question 15

radical forms have an ____

Answer 15

unpaired electron- donates to or acquires electron from cellular molecules

Question 16

ROS associated injury

Answer 16

• lipid peroxidation
• protein degradation
• DNA damage

Question 17

ROS sources

Answer 17

• mitochondria
• inflammation
• exercise
• cigarette smoke
• pollution
• certain drugs, pesticides
• solvents
• reperfusion

Question 18

direct toxic injury and examples

Answer 18

disrupt cellular function;
lead: CNS toxicity;
mercury: CNS toxicity;
carbon monoxide: anemic hypoxia

Question 19

indirect toxic injury and examples

Answer 19

toxic after metabolism;
ethanol: CNS and liver toxicity (can also have direct toxicity);
ethambutol (TB drug): toxic optic neuropathy;
cyclosporine: renal toxicity

Question 20

infectious injury direct cellular damage

Answer 20

ex: virus targets cell and causes cell to rupture; bacteria releases toxin that damages the cell

Question 21

infectious injury indirect cellular damage via immune response

Answer 21

collateral damage that comes along with the immune response to an infection; typically normal

Question 22

genetic and metabolic injury can be ___ or ____; they disrupt normal cell function; examples?

Answer 22

acquired; congenital;

sickle cell anemia, fatty liver disease, hepatolenticular degeneration, type 2 diabetes mellitus

Question 23

traumatic injury examples in the eye

Answer 23

• blunt force trauma
• sharp force trauma
• penetrating trauma
• ionizing radiation

Question 24

____ is a response to stress

Answer 24

adaptation

Question 25

adaptation attempts to restore ____; result of altered ____; type depends on cell and stressor

Answer 25

homeostasis; gene expression

Question 26

atrophy

Answer 26

decreased cell size; can be result of injury/decreased use

Question 27

hypertrophy

Answer 27

increased cell size; can be result of exercise, pregnancy; left ventricular hypertrophy caused by obesity/hypertension

Question 28

hyperplasia

Answer 28

increased cell number; ex: calluses form due to mechanical irritation, pregnancy

Question 29

metaplasia

Answer 29

conversion of one cell type to another; in ectropion the exposed conj. may begin to keratinize due to exposure to external environment

Question 30

dysplasia

Answer 30

disorderly growth; not an adaptation but rather damage; a precursor to cancer

Question 31

intracellular and extracellular accumulations as adaptation

Answer 31

- water - lipids - cholesterol - calcium - pigments - ex: bilirubin, lipofuscin

Question 32

primary theories of aging

Answer 32

- accumulation of injurious events - genetically controlled program - likely a combination of both

Question 33

as we age, our cells produce less ____ and more ____, which further reduces the ability to produce ____

Answer 33

ATP; free radicals; ATP

Question 34

necrosis

Answer 34

initiated by (external) cell injury, leads to inflammation; group of cells; type of necrosis that occurs depends on the type of tissue in which it occurs

Question 35

apoptosis

Answer 35

programmed cell death; initiated by suicide gene activation; single cell; orderly and non-inflammatory; body can recycle materials; developmentally necessary; ordered cell turnover; can also result from injury

Question 36

coagulative necrosis

Answer 36

- kidneys, heart, adrenal glands | - begins with ischemia, leads to protein denaturation, cellular lysis, and clotting

Question 37

liquefactive necrosis

Answer 37

- neurons and glial cells of the brain - cells release hydrolytic enzymes which digest tissues into a wet/runny wound - may form abscess or cysts

Question 38

caseous necrosis

Answer 38

- cheese-like - tuberculosis pulmonary infection - combination of coagulative and liquefactive necrosis

Question 39

gangrenous necrosis

Answer 39

clinical term; large area of affected tissue

Question 40

dry gangrene

Answer 40

large area with coagulative necrosis

Question 41

wet gangrene

Answer 41

large area with liquefactive necrosis

Question 42

gas gangrene

Answer 42

associated with anaerobic bacteria that produce gas

Question 43

fat necrosis

Answer 43

- breast, pancreas, and other abdominal organs | - action of lipases may cause saponification (changing of tissue into soapy texture)

Question 44

somatic death

Answer 44

sufficient death of cells/tissues of vital organs: heart, brain, kidneys; occurs when the death of the tissue exceeds the body's ability for normal life processes

Question 45

postmortem changes; useful for investigating unobserved deaths

Answer 45

- algor mortis: cooling of the body - livor mortis: pooling of the blood - rigor mortis: muscle contraction - postmortem autolysis (endogenous) and putrefaction (exogenous)