Cell injury, degeneration and death

Question 1

What would be the outcome of damage to the mitochondria?

Answer 1

disrupted aerobic respiration/ATP synthesis

Question 2

What would be the outcome of damage to the cell membrane?

Answer 2

disrupted ion concentrations especially increased calcium ions

Question 3

What would be the outcome of damage to the cytoplasm (inc. ribosomes, etc.)

Answer 3

disrupted enzyme and structural protein synthesis and architecture

Question 4

What would be the outcome of damage to the nucleus?

Answer 4

disrupted DNA maintenance and DNA damage

Question 5

What causes oxidative stress?

Answer 5

• reactive oxygen species (free radicals)

Question 6

How are ROS normally made?

Answer 6

in small amounts as by-product of respiration

Question 7

How are ROS pathologically made?

Answer 7

absorption of radiation, toxic chemicals, hypoxia, etc.

Question 8

Name common signs of reversible change in a cell

Answer 8

• cloudy swelling (osmotic disturbance)
• disrupted microvilli, swollen mitochondria, cytoplasmic blebs
• fatty change (accumulation)

Question 9

Describe necrosis

Answer 9

cell death following injury which is usually uncontrolled and due to external stimuli

N.B. Always pathological

Question 10

Describe apoptosis

Answer 10

Controlled cell death - ‘programmed’

• usually physiological
• can be pathological, e.g. viral infection

Question 11

What is the main difference between apoptosis and necrosis

Answer 11

necrosis = cells burst and contents leak
apoptosis = controlled, no disruption of membrane, requires energy

Question 12

Karyolysis

Answer 12

nucleus fading

Question 13

pyknosis

Answer 13

nuclear shrinkage

Question 14

karyorrhexis

Answer 14

nuclear fragmentation

Question 15

coagulative necrosis

Answer 15

firm, tissue outline retained

• haemorrhagic: due to bloackage of venous drainage
• gangrenous: larger area, especially lower leg

Question 16

colliquitive necrosis

Answer 16

tissue becomes liquid and its structure is lost
(e.g. infective abcess, cerebral infarct)

N.B. occurs particularly in tissues with little fibrous tissue

Question 17

Caseous necrosis

Answer 17

combination of coagulative and colliquitive, appearing cheese like
- classical for granulomatous inflammation, especially TB

Question 18

Fat necrosis

Answer 18

due to action of lipases on fatty tissue

Question 19

What are the effects of necrosis

Answer 19

• functional effects depend on the tissue/organ
• inflammation occurs due to release of cell contents
  > either acute or chronic

Question 20

Name pathological causes of apoptosis

Answer 20

• viral infection
• dna damage
• hypoxia/ischaemia

Question 21

Describe the cell morphology of apoptosis

Answer 21

• cell shrinkage
• chromatin condensation (packaging up of nucleus)
• membranes of cell, etc. remain intact
• cytopplasmic blebs form and break off to form apoptotic bodies, which are phagocytosed by macrophages

Question 22

depositions

Answer 22

abnormal accumulation of substances

Question 23

endogenous depostions

Answer 23

• normal products of metabolism, incl. protein, lipid and carbohydrate
• pigments

Question 24

exogenous depositions

Answer 24

foreign material

• pigments
• industrial material

Question 25

amyloid depositions

Answer 25

abnormal folding of soluble protein fibrils into specific abnormal insoluble aggregates

Question 26

Describe the morphology of amyloid aggregates

Answer 26

resembles fibrosis but without prior inflammation

Question 27

How does amyloid occur?

Answer 27

- excessive production/accumulation of a normal protein; OR - production/accumulation of an abnormal protein; AND - tendency of protein to misfold

Question 28

Name two types of systemic deposition as an example of accumulation of excessive amount of normal protein

Answer 28

AL amyloid - immunoglobulin light chain, produced in B-cell neoplasms AA amyloid - serum amyloid associated protein produced in the liver - produced in prolinged chronic inflammation, e.g. RA

Question 29

Name two types of localised deposition as an example of accumulation of abnormal protein

Answer 29

e.g. alzheimer's, genetic variants

Question 30

Give examples of the outcomes of amyloid in organs

Answer 30

- Kidney: renal impairment or failure - Heart: heart failure - Brain: dementia

Question 31

What is pathological calcification?

Answer 31

deposition of calcium salts

Question 32

What are the types of pathological calcification?

Answer 32

- dystrophic | - metastatic

Question 33

Describe dystrophic pathological calcification

Answer 33

deposition in abnormal tissue with normal serum calcium

Question 34

Describe metastatic pathological calcification

Answer 34

- deposition in normal, living tissue, with raised serum calcium - often in connective tissue of blood vessels - can compromise tissue function

Question 35

What are the causes of raised serum calcium?

Answer 35

increased levels of parathyroid hormone - primary: parathyroid gland tumour - secondary: kidney disease may be systemic effect with cancer