1 Cell Injury

Question 0

How do cells react to severe changes in environmental conditions?

Answer 0

Cell adaptation
Cell injury
Cell death

Question 1

Define ‘disease’

Answer 1

A consequence of failed homeostasis with consequent morphological and functional disturbances to cells.

Question 2

What determines the degree of an injury?

Answer 2

Type of injury
Severity of injury
Type of tissue affected

Question 3

Define ‘cell injury’

Answer 3

Irreversible change within a cell

Question 4

Name 3 causes of cell injury and cell death

Answer 4

Hypoxia
Trauma
Toxins
Radiation
Dietary deficiencies
Micro-organisms
Immune mechanisms

Question 5

Define ‘ischaemia’

Answer 5

Loss of blood supply to a tissue

Question 6

Define ‘hypoxia’

Answer 6

Oxygen deprivation to tissues

Question 7

What is ‘hypoxaemic hypoxia’?

Answer 7

Arterial content of oxygen is low

Question 8

What is ‘anaemic hypoxia’?

Answer 8

Decreased ability of haemoglobin to carry blood

Question 9

What is ‘ischaemic hypoxia’?

Answer 9

An interruption of blood supply

Question 10

What is ‘histiocytic hypoxia’?

Answer 10

Disabled oxidative phosphorylation enzymes so oxygen cannot be utilised.

Question 11

Give 3 examples of toxins

Answer 11

Alcohol
Poison
Illegal Drugs
Asbestos
Pollutants
Medicines

Question 12

What is a ‘hypersensitivity reaction’?

Answer 12

The host tissue is injured after an overly vigorous immune reaction

Question 13

What is an ‘immune reaction’?

Answer 13

The immune system fails to distinguish between self and non-self

Question 14

What are the principle targets for cell damage?

Answer 14

Cell membranes
Nucleus
Proteins
Mitochondria

Question 15

List the 4 effects of a high intracellular Ca2+ concentration

Answer 15

Decreased ATP
Decreased phospholipids
Disruption of protein production
Nuclear chromatin damage

Question 16

What is a ‘free-radical’?

Answer 16

A very reactive molecule with a single unpaired electron in the outer orbit.

Question 17

How are free-radicals produced in the body? When are they excessively produced?

Answer 17

Side products of the electron transport chain.

After chemical and radiation injury

Question 18

How are free-radicals/reactive oxygen species (ROS) neutralised?

Answer 18

Antioxidants eg. H2O2

Question 19

What is ‘ischaemia-reperfusion injury’?

Answer 19

Blood flow returns to a damaged tissue and is reoxygenised causing the production of more ROSs. This makes the damage worse.

Question 20

What is the function of ‘heat-shock’ proteins?

Answer 20

Mend misfolded proteins and maintain cell viability.

Question 21

What is ‘oncosis’?

Answer 21

Cell death with swelling (including the spectrum of changes that occur in injured cells prior to death)

Question 22

Name some cellular symptoms associated with reversible injury

Answer 22

Blebs
Swelling
Clumping of chromatin
Mitochondrial swelling
ER swelling
Dispersion of ribosomes

Question 23

Name some features associated with irreversible injury.

Answer 23

Rupture of lysosomes and autolysis
Defects in the cell membrane
Lysis of ER
Nuclear damage
Myelin figures

Question 24

Describe what is seen in: i. ) Pyknosis ii. ) Karyorrhexis iii. ) Karyolysis

Answer 24

i. ) Accumulation of denatured proteins ii. ) Fragmented nucleus iii. ) No nucleus

Question 25

What is 'necrosis'?

Answer 25

The morphological changes that occur after a cell has been dead some time. The cell contents leak out and inflammation can be seen.

Question 26

Name the 4 types of necrosis

Answer 26

Coagulative Liquefactive Caseous Fat necrosis

Question 27

What happens in 'coagulative necrosis'?

Answer 27

The denaturing of proteins dominates over the release of active proteases. The cellular architecture is preserved as a 'ghost outline'

Question 28

What happens in 'liquefactive necrosis'? Where is it found?

Answer 28

Enzyme degradation is greater than denaturation so the tissues are enzymatically degraded. Found in the brain

Question 29

What can be seen in caseous necrosis? What cause is it associated with?

Answer 29

Structureless debris | Infections, especially TB

Question 30

What happens in fat necrosis? When does it occur?

Answer 30

Adipose tissue is destroyed by lipase release. It occurs after trauma.

Question 31

What is gangrene? Name and describe the two types

Answer 31

Necrosis visible by the naked eye Dry- modified by the air to become hard Wet- modified by infection

Question 32

What is an infarct? How are they caused?

Answer 32

An area of ishaemic necrosis | Clots in blood vessels, compression or twisting of the blood supply

Question 33

When does a white infarct occur?

Answer 33

When there is an arterial deficiency. It only has one blood supply so is not reperfused.

Question 34

When does a red infarct occur?

Answer 34

Venous insufficiency Tissue is reperfused Dual blood supply

Question 35

When can a large potassium leak from a cell occur?

Answer 35

After a large amount of sudden cell death (eg. MI, burns, effective cancer treatment)

Question 36

Why can enzyme leaks from cells be useful clinically? Give an example

Answer 36

Test plasma levels for released enzymes to diagnose problem | Example: troponin levels for MI, ALT/AST levels for liver damage

Question 37

What is a side effect of a large myoglobin release?

Answer 37

Myoglobin blocks renal tubes causing dark urine

Question 38

What is 'apoptosis'?

Answer 38

Programmed cell death with shrinkage

Question 39

How is apoptosis induced?

Answer 39

Enzymes are activated that degrade its own nuclear DNA and proteins

Question 40

How many cells are affected by apoptosis at a time?

Answer 40

1

Question 41

What enzyme mediated apoptosis

Answer 41

p53

Question 42

How are the fragments of the apoptitic cell removed?

Answer 42

Phagocytosis

Question 43

Why do abnormal accumulations occur within a cell?

Answer 43

The cell cannot metabolise the accumulation

Question 44

What is the effect of fluid accumulation?

Answer 44

Swelling

Question 45

What is the effect of lipid accumulation around the liver?

Answer 45

Steatosis and an increased liver size

Question 46

What accumulation does a Mallory's highline-hepatocyte have?

Answer 46

Accumulation of keratin

Question 47

What is 'dystrophic calcification'?

Answer 47

Pathological calcification of areas of localised damaged tissue

Question 48

What is 'metastatic calcification'?

Answer 48

Pathological calcification effecting the whole body and destroying bone tissue