P: week 1

Question 0

what are the 2 types of cell death?

Answer 0

necrosis

apoptosis

Question 1

how do cells respond to stress?

Answer 1

they adapt, if they cannot adapt they become injured

injury = reversible or irreversible

Question 2

describe reversible cell injury?

Answer 2

application of stimulus or stress, that once removed can return to normal state

Question 3

what actually happens in reversible cell injury?

Answer 3

cellular swelling due to 
-> reduced oxidative phosphorylation
-> leading to ATP depletion
-> ATP pump stops working, causing Na to flow in, osmosis, water follows salt => Cell Swells!
also the accumulation of fat

Question 4

what happens to cell after reversible injury? **

Answer 4

• > swelling of endoplasmic reticulum and mitochondria
• > membrane “blebs”, picture bubbling on memebrane
• > clumping of chromatin

Question 5

example of liver cell injury?

Answer 5

hepatocytes - fat accumulation
eg.
stress/applied stimulus = alcohol
if the alcohol were to stop, the cells could recover

Question 6

what happens in irreversible cell death? **

Answer 6

• severe mitochondrial damage
• irreversible membrane defects
• lysosomal digestion

Question 7

what happens to the cell AFTER irreversible injury?

Answer 7

first 3 things that happen are the same as reversible injury..THEN
- lysosomal rupture
- myolin figures breakdown products of organelles
=> leading to fragmentation of cell membrane and nucleus

Question 8

is the accumulation of fat reversible or irreversible injury?

Answer 8

reversible!

think fatty liver disease due to alcoholism

Question 9

is the severe damage to mitochondrion reversible or irreversible injury?

Answer 9

irreversible

Question 10

is cell swelling reversible or irreversible injury?

Answer 10

reversible

Question 11

is chromatin clumping reversible or irreversible injury?

Answer 11

reversible

Question 12

define necrosis?

Answer 12

unregulated enzymatic digestion of cell components, loss of cell membrane integrity with uncontrolled release of the products of cell death into the intracellular space, and initiation of the inflammatory response

Question 13

define apoptosis:

Answer 13

controlled autodigestion of cell components due to activation of endogenous enzymes

Question 14

how does ATP depletion cause swelling?

Answer 14

sodium and water move into cell and potassium moves out of cell

• osmotic pressure increases
• more water moves in(follows salt Na)

Question 15

what are the principle mechanisms of cell injury?

Answer 15

1. decrease ATP, mitochondrial damage
2. entry of Ca2+
3. increased oxidative stress(free radicals)
4. membrane damage - defects in membrane permeability
5. protein misfolding DNA damage

Question 16

what are free radicals?

Answer 16

have an unpaired electron in outer orbit

- molecules that react with free radicals themselves turn into free radicals = chain reaction

Question 17

what does injury mechanism influx of calcium cause?

Answer 17

activation of ATPases, Endonucleases and Proteases

Question 18

what does injury mechanism damage to mitochondria cause?

Answer 18

release of cytochrome C into the cytoplasm

Question 19

what does injury mechanism oxidative stress cause?

Answer 19

lipid peroxidation

Question 20

what does injury mechanism damage to DNA and proteins cause?

Answer 20

activation of apoptosis after failure of DNA repair

Question 21

what does injury mechanism ATP depletion cause?

Answer 21

failure of Sodium potassium pump and cell swelling

Question 22

what does injury mechanism defects in membrane permeability cause?

Answer 22

leakage of lysosomal enzymes into cytoplasm

Question 23

major causes of ATP depletion as a principle mechanism of cell injury

Answer 23

• reduced supply of oxygen and nutrients
• mitochondrial damage
• toxins

Question 24

major causes of damage to mitochondia as a principle mechanism of cell injury

Answer 24

• increased cytosolic calcium
• reactive oxygen species
• oxygen deprivation

Question 25

major causes of influx of calcium as a principle mechanism of cell injury

Answer 25

• increased influx across plasma membrane
• ischaemia and certain toxins
• release of calcium from the intracellular stores

Question 26

define hypertrophy:

Answer 26

existing muscles cells get bigger

=> increase in functional capacity

Question 27

define hyperplasia:

Answer 27

increase in number of cells

eg. calluses, unusual hardening of skinn

Question 28

why does the difference of hyperplasia and hypertrophy exist?

Answer 28

cell characteristics…not all cells can divide

• Labile cells can divide easily
• Stable cells can undergo hyperplasia and regenerate
• Permanent cells cannot undergo hyperplasia but can undergo hypertrophy

Question 29

what can cause atrophy?

Answer 29

• reduced functional demand
• inadequate O2
• insufficient nutrients
• persistent cell injury
• endocrine insufficiency

Question 30

define metaplasia:

Answer 30

when one fully differentiated cell type is replaced by another fully differentiated cell type
..why? replacement of stressed cells with cells better equipped to suit the adverse environment
does not result in a change in phenotype of a cell, but is the result of reprogramming of stem cells that exists in normal tissues

Question 31

example of metaplasia?

Answer 31

ciliated columnar epithelial in trachea/bronchi
=> to stratified squamous epithelial

“smokers lungs”

Question 32

metaplasia is not always a harmless adaptive process:

Answer 32

normal > metaplasia > dysplasia > neoplasia

potentially reversible up to dysplasia