2. Cell Injury

Question 1

what is involved in the maintenance of a steady state?

Answer 1

1. preservation of genetic integrity
2. normal enzyme content
3. intact membranes and transmembrane proteins
4. adequate supply of substrates and oxygen

Question 2

what is the reaction of cell to stress?

Answer 2

initially tries to adapt. if it cannot, or if it exposed to an injurious stimulus, it gets injured

Question 3

what are the 2 types of cell injury?

Answer 3

reversible (normal homeostasis)

irreversible

Question 4

what are the 2 types of irreversible cell injury?

Answer 4

necrosis

apoptosis

Question 5

what are the ways in which cells adapt to stress?

Answer 5

1. change in cellular activity

2. change in cell morphology

Question 6

in what ways can the cell alter its activity?

Answer 6

1. increased activity
   - physiological hypertrophy
   - pathological hypertrophy
   - physiological hyperplasia
   - pathological hyperplasia
2. decreased activity
   - physiological atrophy
   - pathological atrophy

Question 7

in what ways can the cell alter its morphology?

Answer 7

metaplasia

dysplasia

Question 8

what is the possible aetiology of cell injury?

Answer 8

1. irradiation, genetic disorders
2. infectious organisms, chemical agents, lack of essential nutrients
3. physical trauma
4. oxygen availability
5. immunological, ageing

Question 9

in what ways can oxygen availability be a problem to cells?

Answer 9

hypoxia - less oxygen
anoxia - absence of oxygen
ischaemia - lack of blood flow, leading to hypoxia
hyperaemia, cyanide poisoning

Question 10

how can the lack of oxygen availability be corrected?

Answer 10

re-oxygenation as a result of re-perfusion of the cell

Question 11

how does physical trauma affect the cells?

Answer 11

causes disruption of cell structure and thrombosis, leads to ischaemia
the vacuum created sucks in dirt, leading to infection and sepsis
extremes of temperature can lead to the denaturation of proteins, formation of ice crystals, and fever

Question 12

how can chemical agents harm cells?

Answer 12

different chemical agents have different modes of action and can harm the cell in different ways

Question 13

give examples of harmful chemical agents to cells

Answer 13

alcohol
tobacco
drugs
poisons
environmental and occupational agents eg. asbestos

Question 14

what is cyanide poisoning?

Answer 14

cyanide binds to cytochrome C oxidase on the ETC and inactivates it. therefore, it prevents the electron from binding to oxygen and the formation of ATP as well

Question 15

how do bacteria harm cells?

Answer 15

releasing different types of toxins, classed into endotoxins and exotoxins

Question 16

how do viruses harm cells?

Answer 16

hijack protein synthesis mechanism of cells, leading to cell lysis

Question 17

how are cells affected by infectious organisms

Answer 17

their individual methods of harming cells, and collateral damage via inflammation

Question 18

how does irradiation harm cells?

Answer 18

generates free radicals and therefore causes direct damage to macromolecules

Question 19

which areas are more sensitive to irradiation?

Answer 19

bone marrow
gonads
intestines

Question 20

which areas are less sensitive to irradiation?

Answer 20

uterus
adrenal glands
pancreas

Question 21

when is an inflammatory response stimulated after being exposed to radiation?

Answer 21

several hours after

Question 22

examples of radiation

Answer 22

x rays
UV light
radioactive particles