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

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

A
Adaptation 
Cell injury (if injurious stimulant or unable to adapt)
2
Q

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

A

Necrosis and apoptosis

3
Q

How might a cell adapt?

A

Increased cellular activity (hyperplasia, hypertrophy)

Decreased cellular activity (atrophy)

Metaplasia

4
Q

What are the causes of cell injury? (5)

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

Also developmental/genetic disorders, nutritional, ageing

5
Q

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

A

Ischaemia

6
Q

What is a secondary harmful effect of lack of oxygen?

A

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

7
Q

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

A

Body can respond with reactive oxygen species

8
Q

5 things that cause microbial damage

A
Viral
Bacterial exotoxins 
Yeast
Fungi
Intercellular parasites
9
Q

2 ways immunological damage can happen

A

Antigen-antibody complex deposition

Cells are not recognised as self and are attacked

10
Q

How could physiologically present ‘chemicals’ cause damage?

A

If present in wrong concentration

11
Q

6 mechanisms of cell injury

A
Lack of ATP
Mitochondrial damage
Altered intracelluar Ca2+ levels 
ROS
Membrane damage
Protein denaturation
12
Q

What is a sublethal cell injury?

A

Cell swelling and fatty changes

13
Q

How does lack of ATP injure the cell?

A

Ion gradients can’t be maintained

14
Q

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

A

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
Q

How does altered intracellular calcium levels damage the cell?

A
  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
Q

What are reactive O2 species?

A

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

17
Q

Which species detoxify free radicals?

A

Superoxide dismutase

Antioxidants

18
Q

Is necrosis active or passive?

A

Passive

19
Q

Why does necrosis occur?

A

Lethal cell injury

20
Q

What process does necrosis incite?

A

Inflammation

21
Q

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

A
Coagulative (most common)
Caseous
Colliquative
Gangrenous (wet and dry)
Fat
Fibrinoid
22
Q

Describe coagulative necrosis

A

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
Q

Describe caseous necrosis

A

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

24
Q

Describe colliquative necrosis

A

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

25
Q

Describe dry gangrenous necrosis

A

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

26
Q

Describe wet gangrenous necrosis

A

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

27
Q

Is apoptosis passive or active?

A

Active, requires ATP

28
Q

Give an example of physiological apoptosis

A

Embryology, elimination of self-reacting lymphocytes

29
Q

How is apoptosis initiated?

A

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

30
Q

Difference between necrosis and apoptosis: number of cells

A

Necrosis many, apop 1

31
Q

Difference between necrosis and apoptosis: cells enlarge or shrink?

A

Necrosis enlarge, apoptosis shrink

32
Q

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

A

N: fragmentation
A: pyknosis, karyorrhexis, karyolysis

33
Q

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

A

N: disrupted
A: intact

34
Q

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

A

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

35
Q

Difference between necrosis and apoptosis: inflammation?

A

N: yes
A: no

36
Q

Difference between necrosis and apoptosis: pathological or physiological?

A

N: always path
A: often phys