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Flashcards in Cell Injury And Death Deck (36):
1

What are two outcomes of a stimulus being applied to a cell?

Adaptation
Cell injury (if injurious stimulant or unable to adapt)

2

If a cell injury is irreversible what are the two outcomes?

Necrosis and apoptosis

3

How might a cell adapt?

Increased cellular activity (hyperplasia, hypertrophy)

Decreased cellular activity (atrophy)

Metaplasia

4

What are the causes of cell injury? (5)

1. Oxygen availability
2. Physical trauma
3. Microbial
4. Immunological
5. Chemical

Also developmental/genetic disorders, nutritional, ageing

5

What is often a cause of cell injury caused by oxygen availability?

Ischaemia

6

What is a secondary harmful effect of lack of oxygen?

Reperfusion, phagocytes response to injured tissue, inflammatory response, reactive O2 and nitrogen species produced

7

What can be the effect of physical trauma, other than the obvious?

Body can respond with reactive oxygen species

8

5 things that cause microbial damage

Viral
Bacterial exotoxins
Yeast
Fungi
Intercellular parasites

9

2 ways immunological damage can happen

Antigen-antibody complex deposition

Cells are not recognised as self and are attacked

10

How could physiologically present 'chemicals' cause damage?

If present in wrong concentration

11

6 mechanisms of cell injury

Lack of ATP
Mitochondrial damage
Altered intracelluar Ca2+ levels
ROS
Membrane damage
Protein denaturation

12

What is a sublethal cell injury?

Cell swelling and fatty changes

13

How does lack of ATP injure the cell?

Ion gradients can't be maintained

14

Other than contributing to ATP depletion, how does mitochondrial injury cause cell injury?

Triggers caspase-mediated apoptotic cascades that = death of cell
Clumping of nuclear chromatin
Cellular swelling due to ion concentration changes
Lipid deposition due to protein synthesis reduction

15

How does altered intracellular calcium levels damage the cell?

1. Mitochondrial membranes more permeable.
2. Dysregulation of many calcium dependent processes.
3. Increased calcium activates enzymes- ATPases, phospholipases, proteases etc could all damage cells.

16

What are reactive O2 species?

Species with unpaired electrons or more stable but still reactive compounds such as hydrogen peroxide.

17

Which species detoxify free radicals?

Superoxide dismutase
Antioxidants

18

Is necrosis active or passive?

Passive

19

Why does necrosis occur?

Lethal cell injury

20

What process does necrosis incite?

Inflammation

21

What are 6 types of necrosis? Which is most common?

Coagulative (most common)
Caseous
Colliquative
Gangrenous (wet and dry)
Fat
Fibrinoid

22

Describe coagulative necrosis

Denaturation of intracytoplasmic protein. Dead tissue firm and swollen, retains microscopic architecture. Typical of ischaemic injury (except brain). Cellular proteins may leak into blood (e.g. MI diagnosis)

23

Describe caseous necrosis

Characteristic of TB. Cheese like, cellular detail destroyed and surrounded by granulomatous infection. Dead tissue lacks structure

24

Describe colliquative necrosis

Due to some infections or in the CNS LACK OF INFECTION. Liquefaction and cyst formation

25

Describe dry gangrenous necrosis

Largely sterile. Ischaemia secondary to atherosclerosis or diabetes. Tissue dry and black (Hb breakdown). Form of coagulative necrosis.

26

Describe wet gangrenous necrosis

Affects mucosae. Feature of pressure sores. Tissue oedematous and putrid. Coagulative --> liquefactive necrosis. Pressure sores. Infected dry gangrene

27

Is apoptosis passive or active?

Active, requires ATP

28

Give an example of physiological apoptosis

Embryology, elimination of self-reacting lymphocytes

29

How is apoptosis initiated?

Extrinsic signal- P53 if DNA damage. Bcl-1. Caspase enzyme cascade.

30

Difference between necrosis and apoptosis: number of cells

Necrosis many, apop 1

31

Difference between necrosis and apoptosis: cells enlarge or shrink?

Necrosis enlarge, apoptosis shrink

32

Difference between necrosis and apoptosis: what processes occur to the cells?

N: fragmentation
A: pyknosis, karyorrhexis, karyolysis

33

Difference between necrosis and apoptosis: what happens to the plasma membrane?

N: disrupted
A: intact

34

Difference between necrosis and apoptosis: what happens to cell contents?

N: enzymatic digestion of leaked contents
A: cell contents intact

35

Difference between necrosis and apoptosis: inflammation?

N: yes
A: no

36

Difference between necrosis and apoptosis: pathological or physiological?

N: always path
A: often phys