Lecture 1 - Cell injury

Question 1

what is aetiology the study of?

Answer 1

The causative agents of a disease

Question 2

what are the two possible pathways for reversible cell injury?

Answer 2

1. cell recovers and returns to normal functioning cell
2. irreversible cell injury leading to cell death

Question 3

what is hydropic swelling?

Answer 3

poor ATP production = malfunction of Na/K pump = excessive Na+ influx into cell = water follows Na+

characterised by large, pale cytoplasm, dilated ER and swollen mitochondria

Question 4

what is megaly?

Answer 4

when an organ increases in size and weight
e.g. splenomegaly = enlarged spleen

Question 5

what are the four main terms associated with cellular adaptations?

Answer 5

Atrophy
hypertrophy
hyperplasia
metaplasia

Question 6

what is atrophy of a cell?

Answer 6

decrease in cellular size

Question 7

what is hypertrophy?

Answer 7

Increase in cellular size

Question 8

what is hyperplasia?

Answer 8

cells increase in number by increasing rate of mitosis

Question 9

what is metaplasia?

Answer 9

cells change from one type to another

Question 10

what is dysplasia?

Answer 10

A maladaptive cellular adaptation

abnormal or disorderly growth of cells within tissue that can often lead to cancer

Question 11

what causes cell injury?

Answer 11

When a stress exceeds the cells ability to adapt

Question 12

what is apoptosis and what is the process of breakdown?

Answer 12

programmed cell death that allows cell to be replaced with a better functioning one.

death signal receptors activate cascade of reactions
= cell shrinks and forms blebs, proteins break down cell components
= DNA fragmentation occurs in nucleus
= fragments are captured in apoptotic bodies (membrane bound structures)
= bodies undergo phagocytosis and lysis (rupture of cell wall/membrane)

Does not result in inflammation

Question 13

what is necrosis and what are the 6 stages?

Answer 13

unplanned cell death and autolysis (digestion by own enzymes)

1. pathological stimulation
2. cell enlargement
3. loss of membrane activity
4. leakage of content
5. Inflammation
6. nuclear degeneration

Question 14

what are the four types of necrosis?

Answer 14

Coagulative
liquefactive
caseous
fat

Question 15

what is coagulative necrosis characterised and caused by?

Answer 15

Protein denaturation causing coagulation

usually results from hypoxia casued by ischemia (restriction of blood flow)

Question 16

what is liquefactive necrosis characterised and caused by ?

Answer 16

rapid release of lysosomal enzymes which liquefies cell

follows ischemic injury to neurons and glial cells in brain

Question 17

What type of gangrene results from liquefactive necrosis?

Answer 17

bacterial infection causes necrosis and results in wet gangrene which releases toxins and can be life threatening

Question 18

what is caseous necrosis caracterised and caused by?

Answer 18

characteristic of lung tissue damaged by TB

resulting in white, soft lung tissue which is walled off from the rest of the lung by WBCs

Question 19

what is the cause of fat necrosis

Answer 19

usually caused by trauma or pancreatitis

damage causes cells to release triglycerides which are hydrolyzed by pancreatic lipase

Question 20

what is gas gangrene characterised by?

Answer 20

bubbles of gas in damaged tissue

produce toxins and degradative enzymes

Question 21

what are common causes of cell injury?

Answer 21

• lack of oxygen
• lack of nutrients = e.g. diabetes
• infection/immune response = bacteria and viral infections, endo and exotoxins
• chemicals = toxins and poisons
• physical factors = biology of aging

Question 22

what are the four mechanisms of aging?

Answer 22

1. cellular change (genetic, environmental, behavioural)
2. hormonal degradations (synthesis and secretion deduction)
3. Immune function decline
4. Degenerative extracellular change (free radical damage, telomers shorten etc)