13 and 14. Exogenous injury

Question 1

most common cause of cellular injury

Answer 1

hypoxia

Question 2

what is hypoxaemia?

Answer 2

reduced availability of atmospheric oxygwn

Question 3

what is anaemia?

Answer 3

reduced oxygen capacity of blood

Question 4

what is ischaemia?

Answer 4

stagnant/reduced circulation of blood

Question 5

what is ischaemia caused by

Answer 5

blockage of BV

Question 6

what is histoxia?

Answer 6

tissues unable to use available oxygen

Question 7

what is reperfusion injury?

Answer 7

burst of ROS after reoxgenation

Question 8

5 types of exogenous injury

Answer 8

1. physical
2. chemical
3. heat/cold
4. microbial
5. radiation

Question 9

what is contusion?

Answer 9

bruise caused by broken BV

Question 10

describe steps in physical injury

Answer 10

1. trauma causes damage to cells
2. BV ruptures
3. blood leaks into connective tissue
4. RBC phagocytosed by macrophages
5. iron converted to haemosiderin

Question 11

what type of hypoxia does physial injurt cause?

Answer 11

ishaemia

Question 12

what are partial thickness burns

Answer 12

1st and 2nd degree

Question 13

which are well healing;

partial or full thickness burns

Answer 13

partial

Question 14

what are full thickness burns

Answer 14

3rd and 4th degree

Question 15

which skin layers are damaged in 2nd deg burns

Answer 15

epidermis and dermis

Question 16

which skin layers are damaged in 3rd deg burns

Answer 16

all skin layers

Question 17

which skin layers are damaged in 4th deg burns

Answer 17

all skin layers + fascia, bone

Question 18

in which burn degree do axons become damaged

Answer 18

2nd

Question 19

what is a blister mediated by?

Answer 19

histamine

Question 20

what systemic changes occur as a result of heat damage

Answer 20

dramatic release of K+ - causing hypervolaemic shock - irregular heart beating

Question 21

2 ways cold produces damage

Answer 21

indirect (ischaemia ) and direct (freezing of tissues)

Question 22

describe indirect damage of cold

Answer 22

1. cool environment = vasoconstriction
2. reduced blood supply to peripheral tissues
3. when blood supply returns - inflammation + oedema = ischaemia
4. prolonged ischaemia+ oedemia = necorsis

Question 23

what causes the direct freezing of tissues?

Answer 23

ischaemia + direct freezing

Question 24

why does the tissue blacken in direct cold damage

Answer 24

erythrocyte leakage

Question 25

4 harmful effects of chemicals

Answer 25

1. direct action on cell architecure 2. interference with enzyme action 3. toxigenesis 4. carcinogenesis

Question 26

chemical which causes disruption

Answer 26

lead

Question 27

how does Pb lead to change in protein conformation

Answer 27

attaches to sulphydryl and carboxyl groups on the protein

Question 28

how does Pb cause anaemia?

Answer 28

interferes with Hb synthesis - ferochelatase

Question 29

how does Pb cause MS?

Answer 29

Pb interferes with adenylcyclase

Question 30

how does Pb cause kidney problems?

Answer 30

interferes with AA urea

Question 31

effect of damage of Pb on kidney

Answer 31

glycosuria

Question 32

how does formaldehyde and mercury work to interfere with enzyme function?

Answer 32

covalently bind to enzymes - inactivating them

Question 33

how does cyanide cause problems with respiration?

Answer 33

cyanide binds to cytochrome oxidase

Question 34

what are microsomal oxygenases?

Answer 34

enzymes which convert aromatic HCs, CCl4 and aromatic amines into ROS

Question 35

how is CCl4 converted into CCl3?

Answer 35

microsomal oxygenases = cytochrome P450 enzyme

Question 36

mode of action of carcinogens

Answer 36

DNA damage

Question 37

3 ways carcinogens cause DNA damage (genotoxic)

Answer 37

1. base alkylation 2. strand breaks 3. cross linkages of DNA strands

Question 38

3 ways carcinogens cause DNA damage (non -genotoxic)

Answer 38

1. change growth regulatory proteins 2. synergy with viruses 3. promote other toxins

Question 39

what is primary deficiency

Answer 39

inadequate food intake

Question 40

what is secondary deficiency

Answer 40

malnutrition

Question 41

4 mechanisms of microbial damage

Answer 41

1. nutrient deprivation 2. production of toxins 3. antigenicity 4. intracellular growth

Question 42

how does clostridum botulinum work?

Answer 42

produces toxin which prevents release of ACh - leading to paralysis

Question 43

how does mycobacterium tuberculosis work?

Answer 43

produce toxins which have damaging antigenic response = attacking phospholipids and cytoplasmic proteins

Question 44

how does meningitidis work

Answer 44

exist in neutrophil, cause neutrophil death by necoriss and pyrogenic inflammation

Question 45

3 radiating waves

Answer 45

1. cosmic 2. UV 3. ionising - beta, alpha, gamma

Question 46

direct action of radiation

Answer 46

directly alters DNA, RNA

Question 47

indirect action of radiation

Answer 47

ionisation of intra-cellular water causing free radicals