Pathology (Cell Injury and Death)

Question 1

What are the causes of cellular injury?

Answer 1

Oxygen deprivation: hypoxia, ischaemia

Physical agents

Chemical agents and drugs

Infectious agents

Immunological reactions

Genetic dearangements

Nutritional imbalances

Question 2

Describe the pathways in which a healthy cell can take

(Hint: Picture)

Answer 2

Question 3

List 5 Biochemical mechanisms to cell death.

Answer 3

ATP depletion

Oxygen and oxygen derived free radicals

Intracellular calcium and loss of calcium homeostasis

Defects in membrane permeability

Irreversible mitochondrial damage

Question 4

What are the 4 primary targets for cell death?

Answer 4

Mitochondria (hypoxia and hypoglycemia)

Cell membranes (oxygen free radicals)

Cytoskeleton (immune mediated)

Cellular DNA (oxygen free radicals)

Question 5

List 3 (of 7) Reversible cell injuries

Answer 5

O2 and ATP drops

Anaerobic glycolysis

Lactic acid and pH drop

The Na pump failure Na

Na and water in cytoplasm

Swelling and dlation of the ER

Disruption inhibits protein synthesis

Question 6

What are causes of Irreversible cell injury?

Answer 6

Calcium activates certain enzymes such as phospholipases, proteases, ATPases and endonucleases.

Rupture of lysosomes and autolysis

Myelin figures

Defects in cell membrane

Mitochondrial swelling

Question 7

What is Pyknosis?

Answer 7

Smaller, condensed, stained with haemotoxylin of nucleus

Question 8

What is Karyorrhexis?

Answer 8

Fragmentation of nuclei

Question 9

What is Karyolysis?

Answer 9

Complete breakdown of nucleus

Question 10

Name three Free Radical species?

Answer 10

Superoxide anion O2-

Hydroxyl radical OH

Hydrogen Peroxide H2O2

Question 11

How do free radicals damage cells?

Answer 11

Peroxidation of lipid mebranes

Attack thiol groups on proteins

Breakdown DNA

NADPH depletion of mitochondria, leads to calcium in cytosol.

Question 12

What do free radicals react with?

Answer 12

Cell membranes

Proteins

DNA

Mitochondria release Ca into cytoplasm.

Question 13

Are there protective mechanism of free radicals? If so list some.

Answer 13

Yes.

Antioxidants e.g. Vit E

Glutathione Peroxidase

Superoxide dismutase

Catalase

Question 14

What is the morphology of Necrosis?

Answer 14

Cellular swelling

Nuclear and cytoplasmic degradation

Coagulative

Liquidifactive

Caseous

Fatty

Question 15

What is coagulative necrosis?

Answer 15

Outline of cells and architecture of tissue still seen.

Question 16

What is liquefactive necrosis?

Answer 16

Semi-liquid as the result of action of hydrolytic enzymes.

Question 17

What is caseous necrosis?

Answer 17

Dead tissue that resembles cream cheese: characteristic of tuberculosis.

Question 18

What is fat necrosis?

Answer 18

Can occur after liberation of pancreatic enzymes and after trauma to fat tissue.

Question 19

When is apoptosis applicable?

Answer 19

During development

Maintaining cell populations

Defence against invading pathogens and tumour cells

Removal of damaged cells

Natural aging

Question 20

How is apoptosis important in development?

Answer 20

Without apoptosis we wouldn’t have the distinctive fingers and toes that we have. We would instead have webbing between them.

Question 21

How is apoptosis important in homeostasis?

Answer 21

Regulation of cells - e.g. in the intestine

Tumour killing

Removal of viral infected cells

Removal of injured cells - e.g. viral hepatitis

Atopy of organs - obstruction of pancreas, kidney

Question 22

Define hypertrophy

Answer 22

Increase in cell size

Increased synthesis of structural components

No cell division

e.g. Arnold Schwarzenegger and muscle

Question 23

Define hyperplasia

Answer 23

Increase in cell numbers

Distinct from hyperstrophy but they may occur together

e.g. calluses

Question 24

Define metaplasia

Answer 24

Change in cell phenotype

Certain long standing environmental changes have adverse effects on specialised cell types

e.g. barretts oesophagus

Smoking and bronchial epithelium

Question 25

Define dysplasia

Answer 25

Change to abnormal cell phenotype

Question 26

Define neoplasia

Answer 26

Uncontrolled growth of abnormal cell phenotype.

Question 27

Some adaptive responses in cellular adaption are?

Answer 27

Changes in cell size and growth

Changes in cellular differentiation

Intracellular accumulation

Question 28

What are labile or stable cells?

Answer 28

Can divide easily and undergo hyperplasia

Question 29

What are permanent cells?

Answer 29

Cannot divide after birth

Cannot undergo hyperplasia

Can undergo hypertrophy

Question 30

What is atrophy?

Answer 30

Decrease in size and activity of cell

Diminished function

Are not dead and removal of stimulus often causes the cell to revert to normal

Question 31

What are 4 (of 7) pathological causes of atrophy?

Answer 31

Disuse

Denervation

Inadequate nutrition

Loss of endrocrine stimulation

Diminished blood supply

Senile atrophy

Pressure atrophy

Question 32

How does metaplasia occur?

Answer 32

Stem cells are present in most epitheli

These reverse cells are undifferentiated

These undifferentiated mesenchymall cells respond to signals

Question 33

Intracellular Accumulations: Name what it is, an example of where it occurs, and the causes behind this site.

Answer 33

One of the manifestations of metabolic disturbance is the accumulation of material within cells.

A normal cellular constituent

An abnormal substance

or pigment

Liver cells collecting fat due to alcohol consumption

Toxins

Protein malnutrition

Diabetes

Obesity

Anoxia

Alcohol