Response to injury

Question 1

Difference between physiological and pathological stress?

Answer 1

Physiological is cellular response to normal stimulation so hormones and endogenuos chemical

Patholigical adaptation , response to stress to avoid injury

Question 2

What are the 4 types of adaptation

Answer 2

hypertrophy
hyperplasia
atrophy
metaplasia

Question 3

Describe what happens in cell size/number and organ size for the 4 types of adaptation

Answer 3

Hypertrophy, increase in cell size and increase in organ size
Hyperplasia, increase in cell number and increase in organ size
Atrophy due to decrease in cell size/number and decrease in organ size
Metaplasia is change in cell type

Question 4

Define hypertrophy and hyperplasia

Answer 4

Hyperplasia is caused by an increased reproduction rate of cells

Hypertrophy is caused by an increase in volume

Question 5

Are the 4 types of adaptation reversible and if so then how?

Answer 5

Yes reversible if stimulus removed

Question 6

What are the factors of hypertrophy

1) stimuli?
2) cells

Answer 6

The physiological and pathological stimuli is due to increased work load
Increased size of cells resulting in increased size of organ
No new cells, just larger cells
Non-dividing cells increase in size (myocytes, skeletal muscle)
Increased amount of structural organelles and proteins

Question 7

factors of hyperplasia

Answer 7

Growth factor driven proliferation of mature cells and stem cells
Increase in number of cells in organ or tissue
only in cell populations capable of dividing
physiological and pathological stimuli

Question 8

Explain briefly the following physiological stimulis

1) puberty
2) liver resection
3) Low O2

Answer 8

1) Hormonal
2) Compensatory
3) Increased demand due to low atmospheric o2 leads to increased erythrocytes

Question 9

Explain briefly the following pathological stimulis

1) Hormonal
2) Skin warts
3) Callous

Answer 9

1) Endometriosis
2) Viral infection (skin warts)
3) Chronic stress (Callous)

Question 10

Atrophy factors

Answer 10

Decreased amount of structural proteins and organelles due to decreased protein synthesis and increased protein degradation.
Reduced size of organ resulting from decrease in cell size and number

Question 11

When is physiological and pathological atrophy used?

Answer 11

Physiological atrophy is common during normal development (embryonic structures, uterus following pregnancy)

Pathologic atrophy depends of the underlying cause

Question 12

Effects of atrophy

Answer 12

Decreased work load - immobilisation
Loss of innervation
Loss of blood supply
Inadequate nutrition
Loss of endocrine stimulation
Pressue
Aging

Question 13

Metaplasia factors

Answer 13

Replacement of one differentiated cell type with another
Cells sensitive to stress replaced by a cell type better able to withstand stress
Stem cell reprogramming

Question 14

Explain metaplasia using

1) cigarette smoking
2) Chronic gastric reflux

Answer 14

1) Ciliated columnar turns to stratified squamous

2) Stratified squamous turns to gastric columnar epithelial

Question 15

Define the following

1) Adaptation to an injury
2) Reversible/Sublethal injury
3) Irreversible injury

Answer 15

1) A response to stress or increased demand that maintains the
steady state of the cell without compromising cellular function.
2) A response to stress/ stimuli that compromises cellular
function.
3) A response to stress/ stimuli that compromises cellular
function to the point that it cannot recover

Question 16

Reversible injury

1) what happens to cell function
2) is recovery possible and how?
3) organ function
4) example

Answer 16

1) cell function compromised
2) recovery if injury is removed
3) may compromise organ function
4) reversibly injured myocytes (transient ischemia) may be transiently non-contractile which will affect function of the heart

Question 17

Irreversible injury

1) what happens to cell function
2) is recovery possible and how?
3) 2 types of 1)
4) any extra factors?

Answer 17

1) Cell cannot recover so cell death
2) No
3) 2 types of cell death which differ in morphology, cause and roles. Necrosis and apoptosis
4) cell death may have occured before morphological changes become apparent

Question 18

Morphology

Answer 18

Gross or microscopic appearance of cells or tissues

Question 19

Most cells are transparent so what can be one to make them visible?

Answer 19

Stain them

Question 20

Triphenyltetrazolium chloride colours

viable myocardium what colour?

Answer 20

Magenta

Question 21

Haematoxylin and Eosin stains the cytoplasm and nucleus what

Answer 21

Cytoplasm pink

Nucleus purple

Question 22

Haemotoxylin can be considered what type of dye?

1) used to stain what to what colour

Answer 22

A basic due
Stains acidic/basophilic structures a purplish blue.
Stains nucleic acids

Question 23

Eosin

1) what type of dye
2) to what colour
3) can also dye what

Answer 23

1) Stains basic structures, sometimes called eosinophilic
2) To red or pink
3) most proteins

Question 24

Cells may undergo what changes before they are actually visible?

Answer 24

Undergo biomchemical changes and be non viable, so dead before appearance shows

Question 25

Name 3 features of an injured cell that is still reversible

Answer 25

Swelling of ER and Mitochondria
Membrane blebs
Clumping of chromatin

Question 26

Name 5 features of an irreversible injured cell

Answer 26

Swelling of ER and loss of ribosomes
Lysosome rupture
Myelin figures
Nuclear condensation
Swollen mitochondria with amorphous densities

Question 27

What are the light microscope and ultrastructural features of reversible injury

Answer 27

Light microscope

• cellular swelling
• fatty change (lipid vacuoles in cytoplasm)

Ultrastructural

• plasma membrane blebbing
• ER and mitochondrial changes
• Nuclear alterations

Question 28

What is necrosis?

Answer 28

Disturbance of membrane function

Inability to reverse mitochondrial dysfunction

Question 29

When does irreversible injury take place?

Answer 29

When mitochondrial dysfunction cant be reversed and when membranes losetheir structural integrity

Question 30

Explain what happens when membranes lose their structural integrity

Answer 30

Lysosomal membranes

• contents leak into cell
• nuclear and cytoplasmic components degraded

Plasma membrane

• loss of osmotic balance
• cellular contents leak into extracellular space, inflammation

Mitochondrial membrane

Question 31

what are the 4 types of abnormalities of essential cellular components and describe them

Answer 31

1) Mitochondrial damage
- decrease in ATP which will affect many other things
- increse in ROS which leads to damage of lipids, proteins, DNA

2) Entry of Ca2+ so affect on calcium homeostasis
- increse in mitochondrial permeability
- activation of multiple cellular enzymes

3) Membrane damage
- plasma
- lysosomal

4) Protein misfolding, dna damage
- activation of pro-apoptic proteins