Week 1: Cell Injury

Question 1

A cell’s response to stress depends on the ________________________ and the _______________.

Answer 1

dose intensity of stressor ; cell’s vulnerability

Question 2

3 basic cellular responses to stress

Answer 2

1) Injury: reduced function / may not be reversible
2) Adaption: Cell takes different forms
3) Death: cessation of cellular activity

Question 3

What are the criteria for irreversible cell injury?

Answer 3

When ATP drops below certain level or when membranes are damaged beyond repair

Question 4

Energy-dependent functions of a cell fail due to what?

Answer 4

ATP depletion which results from hypoxia or anoxia

Question 5

What does mitochondrial damage usually result from?

Answer 5

Genetic disorders
Toxins
Medications

Question 6

If a cell is subject to lots of ROS, toxins or trauma, what might that cause?

Answer 6

An increase in permeability of the cell membrane

Question 7

What does an accumulation of DNA or misfolded proteins result from?

Answer 7

Ionizing radiation

Reactive oxidative stress (ROS)

Question 8

7 common causes of cell injury

Answer 8

Toxins
Infections
Genetic and metabolic diseases
Trauma
Reactive oxidative stress (ROS) 
Inflammatory responses
Hypoxia and Anoxia

Question 9

What is the initial response of a cell when they are low on oxygen? What happens to the cell? Why is this a problem?

Answer 9

Initial response is to switch to anaerobic respiration but this produces less ATP for the cell which can cause problems over long periods of time.

The cell begins to swell since the sodium potassium pumps are not able to use ATP. More sodium goes into cell which is followed by water. This causes swelling.
Also, failure of sodium calcium exchange.

Question 10

Most common cell injury

Answer 10

Hypoxic injury

Question 11

Reduction in oxygen

Answer 11

Hypoxia

Question 12

Absence of oxygen

Answer 12

Anoxia

Question 13

Loss of oxygen due to insufficient blood flow

Answer 13

Ischemic hypoxia/ anoxia

Question 14

Most common form of hypoxia

Answer 14

Ischemic hypoxia

Question 15

Iron-deficiency anemia, carbon monoxide poisoning

Answer 15

Anemic hypoxia

Question 16

What do radical forms of ROS have?

Answer 16

They have an unpaired electron which makes them very reactive. They are partially REDUCED forms of oxygen and are energetically unstable.

Question 17

Describe Reactive Oxidative Species (ROS). Give 4 examples. Their forms. What neutralizes them?

Answer 17

Produced in mitochondria during ATP production, produced by immune cells. Examples include hydrogen peroxide, superoxide, nitric oxide, ozone. Can be in radical or non-radical forms. They break covalent bonds between molecules and can cause damage. Neutralized by anti-inflammatories.

Question 18

3 associated injuries due to reactive oxygen species (ROS)

Answer 18

Lipid per oxidation
Protein Degradation
DNA damage

Question 19

3 oxygen-derived free radicals

Answer 19

1) O2 - superoxide
2) H202 - hydrogen peroxide
3) OH - Hydroxyl

Question 20

Anti-oxidants that neutralize ROS

Answer 20

Superoxide dismutase
Peroxidases
Catalase
Antioxidants

Question 21

2 Occular effects of unchecked ROS

Answer 21

Cataracts

ARMD

Question 22

3 examples and effects of direct toxicity

Answer 22

Lead - CNS toxicity
Mercury - CNS toxicity
Carbon Monoxide - Anemic hypoxia

Question 23

3 examples and effects of indirect toxicity

Answer 23

Ethanol - CNS and liver toxicity
Ethanbutol - Toxic Optic Neuropathy
Cyclosporine - Retinal toxicity. Immunosupressant and Restasis

Question 24

What type of injury is an infection?

Answer 24

Direct or indirect damage

Question 25

What is Ethambutol used for? What are its effects on the eyes?

Answer 25

- Used to treat TB and MAC - Causes vision loss as side effect - painless progressive LOV, decreased VA - central/centrocecal scotoma - optic nerve becomes pale over time - no safe dosage, greater than 15 mg is toxic - can start to lose vision as soon as 2 weeks

Question 26

True or false: | Normal immune responses can someetimes cause damage to the surrounding healthy tissues.

Answer 26

True

Question 27

Things produced in immune response and inflammatory response that can be damaging

Answer 27

``` Phagocytic cells Antibodies Complement Enzymes Free Radicals ```

Question 28

Describe genetic and metabolic injury

Answer 28

Flawed genetic codes cause disruptions in normal cellular behavior which typically lead to cell injury and death

Question 29

4 examples of metabolic and genetic injuries

Answer 29

Sickle Cell anemia Fatty liver disease Hepatolenticular Disease Type 2 diabetes

Question 30

Explain Hepatolenticular Disease. What kind of injury is it? What is its relevance to the eyes?

Answer 30

- Genetic/metabolic injury - Body can't remove excess iron. - Defect in ATP7B protein. Creates free radicals which create holes in membrane. Iron goes through membrane and transported to other tissues. - Iron can be transported to the Descemet's membrane of the cornea and can be seen as rings near the limbus called Kayser Fleisher rings.

Question 31

4 types of traumatic injuries

Answer 31

Blunt force trauma Sharp force trauma Penetrating trauma Ionizing radiation

Question 32

Cells shrink and reduce their differentiated functions

Answer 32

Atrophy

Question 33

Increased cell size

Answer 33

Hypertrophy

Question 34

Increased cell number

Answer 34

Hyperplasia

Question 35

Potentially transform into cancerous tissue

Answer 35

dysplasia

Question 36

Conversion of one cell type to another

Answer 36

Metaplasia

Question 37

Two primary theories of aging

Answer 37

1) Accumulation of injurious events | 2) Genetically controlled programs

Question 38

Initiated by cell injury, leads to inflammation

Answer 38

Necrosis

Question 39

The more specialized a cell, the more ____________ it is to injury

Answer 39

vulnerable

Question 40

Clumping of chromatin in nucleus

Answer 40

Pyknosis

Question 41

Fragmentation of the nucleus

Answer 41

Karyorrhexis

Question 42

Nuclear dissolution of chromatin lysis

Answer 42

Karyolysis

Question 43

Pyknosis, karyolysis, and karyorrhexis in order

Answer 43

Pyknosis, karyorrhexis, then karyolysis

Question 44

loss of electron

Answer 44

oxidation

Question 45

gain electron

Answer 45

reduction

Question 46

Describe reperfusion. Give examples

Answer 46

When there is schema hypoxia, reactive species are created without oxygen. Then, blood flow gets reintroduced and interacts with those molecules and can worsen injury. Examples: Transplant myocardial infarction (heart attack) stroke

Question 47

What does carbon monoxide do?

Answer 47

Direct toxin. | Binds to hemoglobin and displaces oxygen

Question 48

Immune cells produce ____ that attack ______________

Answer 48

ROS ; cellular membranes

Question 49

cooling of the body during death

Answer 49

algor mortis

Question 50

pooling of blood during death

Answer 50

livor mortis

Question 51

muscle contraction during death

Answer 51

rigor mortis