Cell Injury

Question 1

Define hypoxaemic hypoxia

Answer 1

Arterial content of oxygen is low

Question 2

What could cause hypoxaemic hypoxia?

Answer 2

Reduced inspired partial pressure of oxygen at high altitude

Reduced absorption secondary to lung disease

Question 3

Define anaemic hypoxia

Answer 3

Decreased ability of haemoglobin to carry oxygen

Question 4

Define ischaemic hypoxia

Answer 4

Interruption to blood supply

Question 5

Define histiocytic hypoxia

Answer 5

Inability to utilise oxygen in cells due to disabled oxidative phosphorylation enzymes

Question 6

What are the main targets in cell damage?

Answer 6

Cell membranes
Nucleus
Proteins
Mitochondria

Question 7

What is the pathogenesis of cell injury due to hypoxia?

Answer 7

Decreased oxidative phosphorylation, decreased ATP
Detachment of ribosomes
Na+-K+ pump disabled
Influx of calcium, water and Na+, efflux of K+
Leads to swelling, loss of microvilli, blebbing, ER swelling and myelin figures
Increased anaerobic respiration - decreased pH, chromatin clumping

Question 8

What kinds of enzymes are activated by increased intracellular calcium?

Answer 8

ATPases
Phospholipase S
Proteases
Endonucleases

Question 9

What are the 3 ways of generating hydroxyl ions?

Answer 9

Directly by radiation lysis of water
Fenton reaction (Fe2+)
Haber-Weiss reaction

Question 10

Oxidative phosphorylation can yield which ROS?

Answer 10

Superoxide

Hydrogen peroxide

Question 11

Which 2 enzymes act as antioxidants?

Answer 11

Superoxide dismutase

Catalase

Question 12

What are the causes of ischaemic reperfusion injury?

Answer 12

Increased production of free radicals
Increased number of neutrophils - more inflammation and injury
Delivery of complement proteins and activation of the complement pathway

Question 13

What are heat shock proteins?

Answer 13

Proteins that aim to mend misfolded proteins and maintain cell viability

Question 14

Define pyknosis

Answer 14

Irreversible condensation of chromatin

Question 15

Define karyorrhexis

Answer 15

Destructive fragmentation of the nucleus

Question 16

Define karyolysis

Answer 16

The complete dissolution of chromatin due to endonucleases

Question 17

Which cell injury changes are reversible?

Answer 17

Blebs
General swelling
Chromatin clumping
ER swelling 
Detachment of ribosomes
Mitochondrial swelling

Question 18

Which cell injury changes are irreversible?

Answer 18

Defects in cell membranes
Myelin figures
Lysis of ER
Rupture of lysosomes
Pyknosis
Karyorrhexis 
Karyolysis

Question 19

Define necrosis

Answer 19

The morphological changes in a living organism that occur after a cell has been dead sometime.

Question 20

What are the 2 main types of necrosis?

Answer 20

Coagulative

Liquefactive

Question 21

What are the 2 special types of necrosis?

Answer 21

Caseous

Fat

Question 22

Describe the features of coagulative necrosis

Answer 22

Denaturation of proteins dominates
Ghost outlines
Increased pink staining
Many nuclei disappear
Inflammation

Question 23

Describe the features of liquefactive necrosis

Answer 23

Enzyme lysis of proteins dominates
Lots of neutrophils - pus
Lack of collagenous matrix present
Lots of swelling and inflammation

Question 24

Describe the features of caseous necrosis

Answer 24

Contains structureless debris
No ghost outlines
Associated with infections (especially TB)

Question 25

Describe the features of fat necrosis

Answer 25

Usually in abdomen but also in breast Forms chalky deposits/calcium salts with tissue Can be seen on X-rays Result of pancreatitis (lipase release) or direct trauma to adipose tissue

Question 26

What are the 2 types of gangrene and what defines them?

Answer 26

Dry - exposure to air | Wet - infection forming

Question 27

What is gas gangrene?

Answer 27

A type of wet gangrene where anaerobic bacteria get under the skin and create bubbles of gas.

Question 28

What does the degree of injury depend on?

Answer 28

Type of injury Severity of injury Type of tissue

Question 29

The consequences of infarcts depends on ...

Answer 29

Alternative blood supply Speed of ischaemia Tissue involved Oxygen content of blood

Question 30

If muscle is damaged, what is release and how do we know?

Answer 30

Myoglobin | Urine will be brown

Question 31

What are the 3 phases of apoptosis?

Answer 31

Initiation, Execution and Degradation

Question 32

Describe the intrinsic pathway of apoptosis

Answer 32

DNA damage leads to p53 activation Increases mitochondrial permeability Apoptosome generated Cascade initiated

Question 33

Describe the extrinsic pathway of apoptosis

Answer 33

Ligands bind to receptors on the cell surface to activated a cascade in the cell. (Eg. TRAIL activates caspase-8)

Question 34

Which molecules make up the apoptosome?

Answer 34

Cytochrome C APAF 1 Caspase 9

Question 35

What is the function of Bcl-2?

Answer 35

Prevents cytochrome C release from mitochondria so prevents apoptosis.

Question 36

What is haemosiderin?

Answer 36

An iron storage molecule that forms when there is excess iron due to haemorrhage.

Question 37

What occurs in haemosiderosis?

Answer 37

Deposition of iron throughout many organs

Question 38

What happens in hereditary haemochromatosis?

Answer 38

Iron deposited in endocrine organs, associated with scarring and can lead to diabetes.

Question 39

Which types of hepatitis are transmitted orally?

Answer 39

A | E

Question 40

Which types of hepatitis are transmitted in blood?

Answer 40

B | C