Injuries to cells

Question 1

What can stress of the cell lead to?

Answer 1

-cell adaptation and if cell cant adapt cell injury

Question 2

Cell injury is reversible, what happens if it is irreversible?

Answer 2

cell death, by either :

• necrosis
• apoptosis

Question 3

Cell adaptation has four main types what are these?

Answer 3

• Hyperplasia
• Hypertrophy
• metaplasia
• atrophy

Question 4

What happens with hyperplasia?

Answer 4

increase in number of cell

normally results in large organ

Question 5

Give a pathological and physiological example of hyperplasia.

Answer 5

• Pathological = endometrial hyperplasia if hormone stimulus continues (gets to much cells than normal, can progress on to cancer)
• Physiological = menstrual cycle

Question 6

What is hypertrophy?

Answer 6

increase in cell size

Question 7

What is a physiological example of hypertrophy?

Answer 7

• body builders when their muscles get bigger

Question 8

What is a pathological example of hypertrophy?

Answer 8

• heart in hypertension (when high blood pressure causes heart to work harder, thickening of left ventricular wall)

Question 9

What is atrophy?

Answer 9

shrinkage of the cell due to loss of cell substance

Question 10

Why may cause atrophy ?

Answer 10

• decreased workload
• general ageing process
• reduced blood supply
• inadequate nutrition
• loss of hormonal stimulation

Question 11

What happens in metaplasia?

Answer 11

• when one adult cell type is replaced by another adult cell type

Question 12

What is an example of metaplasia ?

Answer 12

chronic gastro-oesophageal reflux or Barretts oesophagus

Question 13

In barrett’s oesophagus what happens?

Answer 13

squamous epithelium changes to columnar epithelium due to acid reflux leaking in to lower end of the oesophagus ad causing damage

Question 14

Is metaplasia reversible?

Answer 14

yes

Question 15

What are the 3 most common causes of cell injury?

Answer 15

• Hypoxia ( low oxygen supply)
• Ischaemia (loss of blood supply leading to low oxygen and nutrients)
• Chemical exposure ( eg. smoking, alcohol, paracetamol)

Question 16

What are the other causes of cell injury?

Answer 16

• infection
• radiation
• immunologic reactions
• ageing

Question 17

What are the findings of reversible cell injury (when looking under a microscope)?

Answer 17

• cellular swelling

- fatty change

Question 18

Cell death occurs via two main pathways, what are these?

Answer 18

necrosis and apoptosis

Question 19

Which cell death pathway causes local inflammation?

Answer 19

necrosis

Question 20

How does apoptosis and necrosis cause cell death?

Answer 20

necrosis - damage to cell membrane allows enzymes to digest the cell
Apoptosis - programmed cell death. irreparable damage to cells DNA or deprived of growth factors

Question 21

Is necrosis pathological or physiological?

Answer 21

it is always pathological

Question 22

Is apoptosis pathological or physiological?

Answer 22

both

Question 23

In apoptosis how are dead cells rapidly removed?

Answer 23

phagocytosis

Question 24

When is physiological apoptosis needed?

Answer 24

• to get rid of cells which have served their purpose

- to get rid of potentially harmful self-reactive lymphocytes

Question 25

Give an example of physiological apoptosis when it is supposed to occur.

Answer 25

- embryogenesis | - Involution of hormone dependent tissues upon hormone deprivation ( uterus in postmenopausal women )

Question 26

When might pathological apoptosis occur?

Answer 26

- DNA damage ( radiation) - certain infections ( hepatitis ) - cell death induced by cytotoxic T cells

Question 27

What does apoptosis result from ?

Answer 27

enzymes called caspases

Question 28

What are the types of necrosis?

Answer 28

- coagulative - liquefactive - caseous - fat These describe what the necrosis looks like after it has died

Question 29

What is an example of where coagulative necrosis may occur?

Answer 29

Heart attack

Question 30

What does caseous necrosis look like ?

Answer 30

cheese

Question 31

What is the most common type of necrosis?

Answer 31

coagulative

Question 32

Coagulative necrosis most commonly occurs after...

Answer 32

- infection | - loss of blood supply

Question 33

What is caseous necrosis normally?

Answer 33

TB | -Can be fungus but normally air on the side of caution and presume its TB

Question 34

What is liquefactive necrosis common with ?

Answer 34

common with brain injuries or brain infarctions or strokes

Question 35

What is fat necrosis ?

Answer 35

is death of fat tissue

Question 36

Which necrosis do you often get a hole in the brain ?

Answer 36

liquefactive necrosis

Question 37

Why does fat necrosis occurs

Answer 37

occurs due to activation of lipases

Question 38

What is a common example of fat necrosis ?

Answer 38

breast damage can be secondary to trauma normally relatively benign process

Question 39

What are the mechanisms of cell injury?

Answer 39

- depletion of ATP - mitochondrial damage - influx of calcium - oxidative stress - damage to the cell membrane - DNA damage

Question 40

What are the effects of depletion of ATP?

Answer 40

- ATP dependent sodium pumps ( electrolyte imbalance) - Increase intracellular lactic acid - failure of calcium pump (electrolyte imbalance) - damage to protein structures

Question 41

What are the effects of mitochondrial damage?

Answer 41

- failure of production of energy | - failure of free radical production

Question 42

What are the effects of influx of calcium?

Answer 42

- increased intracellular calcium - this leads to activation of enzymes - may trigger apoptosis

Question 43

Influx of calcium most commonly happens after what?

Answer 43

``` ischaemic injury (lack of blood supply after poisons ```

Question 44

Oxidative stress may happen after?

Answer 44

paracetamol overdose

Question 45

What happens after defects in membrane permeability?

Answer 45

- results in necrosis | - various sites of damage this results in proteins and electrolytes being in the wrong place

Question 46

When may damage to DNA and proteins happen?

Answer 46

- After radiation injury or oxidative stress

Question 47

What can damage to DNA lead to ?

Answer 47

can result in apoptosis

Question 48

what happens in intracellular accumulation normally due to alcohol misuse?

Answer 48

fat in hepatocytes (fatty liver)

Question 49

If you get intracellular accumulation of cholesterol in smooth muscle cells what does this lead to ?

Answer 49

atherosclerosis

Question 50

What is neoplasia ?

Answer 50

means new growth ( a tumour of some sort)