Cell adaptation + survival

Question 1

What happens to a cell if it is injured?

Answer 1

Can be a non lethal response to injury

Regenerative capacity + intact ECM -> restore to normal function
Regenerative capacity + no ECM -> reduced/loss of function

Question 2

What can cause cell injury?

Answer 2

Lack of factors for growth 
Drugs 
Toxins - alcohol 
Trauma 
Autoimmune,genetic disorders + metabolic disorders

Question 3

Describe hepatocyte blooming as an example of sublethal cell injury

Answer 3

• Cell swelling + pale cells

- Altered beta fat oxidation + metabolic derangement so lipid accumulation

Question 4

Compare apoptosis and necrosis

Answer 4

Apoptosis : Physiological response, break down of single cells using specific enzymes
Necrosis: Not a physiological response, break down of many cells using non specific enzymes

Question 5

What are the 2 types of necrosis?

Give an example

Answer 5

Coagulative: Break down is less rapid and some normal cells will remain but with reduced/loss of function. Maintains tissue structure

Example :
Appears pale and yellow due to inflammatory cell infiltration and + leakage of cell contents

Liquifactive: Rapid degeneration of cells to a liquid mush e.g neurodegeneration + acute cerebral necrosis
Microscopic changes - 6 hours
Eye changes - 12 hours

Question 6

What is the outcome of necrosis dependent on?

Answer 6

Intact ECM -> NORMAL
Non intact ECM-> Repair + scarring
Fibroblasts do not provide the same function so there is loss of tissue function

Question 7

What is gangrenous necrosis ?

What is wet gangrene?

Answer 7

When coagulative necrosis invades several tissue layers ( intestines + limbs). Causes a huge inflammatory response even in the absence of infection
Areas of superimposed bacterial infection

Question 8

What are some examples of controlled apoptosis?

Answer 8

Embyrogenesis - remove webbing of the feet

Cyclical changes in the menstrual cycle allowing breakdown of endometrial tissue

Question 9

Describe apoptosis

Answer 9

Chromatin condenses and cell shrinks
Membrane starts to bleb
Apoptopic bodies form
Apoptopic bodies are phagocytosed by macrophages

Question 10

What can cause decreased apoptosis?

Answer 10

• Mutations in anti apoptopic or pro apoptopic proteins e.g p53
• Mutations in Fas Fas ligand

Question 11

What can cause increased apoptosis?

Answer 11

Neurodegenerative diseases

Question 12

What are some examples of cell adaptations?

Answer 12

Changes in size, cell, no or phenotype

Question 13

What is hypertrophy?

Answer 13

Cell enlargement

Due to increased structural component synthesis due to a stimulus

Question 14

What is hyperplasia and what conditions must be met for it to occur?

Answer 14

Increase in cell number
Cell responses to increased demand via growth factors/physical stretch
Cells must be capable of division e.g lable and stable tissue

Question 15

What is physiological hypertrophy/hyperplasia?

Give an example

Answer 15

Stimulus appropriate for the demand

• Increased cardiac muscle in athletes/pregnancy
• Increased size of uterus

Question 16

What is pathological hypertrophy/hyperplasia?

Answer 16

Stimulus exceeds demand

• Increased volume load on the heart decreased compliance and increases fibrous tissue
• XS steroid production leading to HPC -> cervical cancer

Question 17

What is metaplasia?

Answer 17

One mature cell type replaced by a Different cell type
Due to a chronic irritation
Acts on stem cells causing a different differentiation pathway to occur
Cells have a survival advantage but loss of normal function
Predisposes to neoplastic changes

Question 18

Describe atrophy

Answer 18

Decreased size/no of cells due to less demand ( denervation, disuse, blood supply, age, nutrients)

Cells have increased protein degradation and decreased protein synthesis