Causes Of Cell Injury

Question 0

Define pathogenesis.

Answer 0

The study of the sequence of events from initiation (cause) to conclusion of a disease process.
It is the developmental process of a disease (“who, why, how,and when”).
To understand pathogenesis it is essential to identify the CAUSE and the HOST RESPONSE/TISSUE REACTION and determine the significance.

Question 1

Define etiology

Answer 1

The study of the cause of disease

Question 2

What is the mnemonic for Differential Diagnosis?

Answer 2

VINDICATE

Question 3

What does VINDICATE stand for?

Answer 3

Vascular. 
Infection, inflammatory, immune-mediated. 
Neoplasm. 
Drugs. 
Iatrogenic. 
Congenital/developmental/inherited. 
Anatomic. 
Trauma. 
Environmental exposure/endocrine.

Question 4

What is another mnemonic for Differential Diagnosis?

Answer 4

DAMMIT

Question 5

What does DAMMIT stand for?

Answer 5

Degenerative. 
Autoimmune. 
Metabolic. 
Nutritional/neoplastic. 
Inflammatory/idiopathic/iatrogenic. 
Trauma.

Question 6

What does cell injury refer to?

Answer 6

Refers to damage or pathologic alterations on molecules and structure that can occur in cells and extra cellular components.

Question 7

What are some causes of cell injury? List 5.

Answer 7

O2 deprivation. 
Physical injury. 
Chemical injury. 
Infectious agents. 
Nutritional imbalances. 
Genetic.

Question 8

List and define 6 causes/conditions of O2 deprivation.

Answer 8

1) Hypoxia: inadequate oxygenation of tissues.
2) Ischemia: decrease of blood supply in tissues.
3) Anoxia: absence of O2 in tissues.
4) Anemia: decrease in the # of RBC in blood, or decrease in blood volume, or RBC are deficient in hemoglobin.
5) CO2 toxicity.
6) Cyanide toxicosis: due to blockage of cell respiratory enzymes.

Question 9

What are 5 external agents of physical injury?

Answer 9

Direct mechanical trauma. 
Temp extremes. 
Electrical trauma. 
Radiation. 
Sudden changes in pressure.

Question 10

What effect can trauma have on cells?

Answer 10

Direct rupture or death of large #s of cells

Damage to blood supply to cells.

Question 11

What effect can extreme heat have on cells?

Answer 11

Denatures essential cells enzymes and other proteins.

Question 12

What effect can excessive heat have on cells?

Answer 12

Can increase the rate of metabolic rxns so that substrates, H2O, and pH changes reach lethal levels.

Question 13

What effect can electricity have on cells?

Answer 13

Generates great heat as it passes thru tissue.
Alters conduction to nerves and muscles.
Ex.: lightening and high frequency currents.

Question 14

What effect can ionization radiation have on cells?

Answer 14

Causes ionization of cellular water with production of highly reactive “free radicals”.

Question 15

What effect can radiation have on cells?

Answer 15

Many forms may damage genetic material producing reproductive cell death of cells, genetic defects, neoplasia.

Question 16

What effects can extreme cold have?

Answer 16

Impairs blood flow.

Intracellular ice crystals rupture cell membranes.

Question 17

What are 2 types of radiation and give 3 examples

Answer 17

Radioactive isotope emissions or electromagnetic radiation.

Ex.: UV light, X-ray radiation,cosmic radiation.

Question 18

What are some class types of chemical, drug, and toxin agents (7) and give some examples of each (# varies).

Answer 18

1) Inorganic poisons: Pb, Cu, arsenic, selenium, Hg, etc.
2) Chemicals: drugs (overdose/idiosyncratic), pesticides, herbicides, rodenticides, etc.
3) Physiologic compounds: Na, Glu, O2, etc.
4) Organic poisons: nitrate/nitrite, oxalate, hydrocyanic acid, etc.
5) Plant toxins: ragwort, sweet clover, braken fern, etc.
6) Animal toxins: snake venom, tick toxin, etc.
7) Mycotoxins: aflatoxin, ergot, fusarium, etc.

Question 19

What are the 4 biologic/infectious agents discussed (4) and gave some examples.

Answer 19

1) Acellular agents: viruses, prions
2) Prokaryotes: bacteria, chlamydia, rickettsia, mycoplasma
3) Eukaryotes: fungi, protozoa
4) Metazoan parasites: Cestodes, Nematodes, Trematoda, insects

Question 20

What are some of the effects that viral agents have on cells?

Answer 20

Viruses may cause cell damage by shutting down protein synthesis in host cells and/or by inducing increased membrane permeability and Ca2+ entry.
Viruses can stimulate cytotoxic T-cells that kill infected cells.
Viruses can induce apoptosis.

Question 21

What effect can bacterial agents have on cells?

Answer 21

Causes variable degree of cell damage depending on type of bacteria.
Bacteria produce toxins: exotoxins, cytotoxins, endotoxins.
Damage could be caused by cytotoxins or inflammatory response.

Question 22

Give an example as to who can produce an exotoxins and what effect on the cell does it have?

Answer 22

Clostridium spp.

The release of phospholipases can cause membrane damage.

Question 23

Name 3 spp capable of producing cytotoxins.

Answer 23

Shigella spp.
E. coli
Salmonella spp.

Question 24

What is produced by Gram- bacteria upon their death that has direct toxic effect on cell membranes?

Answer 24

Lipopolysaccharide (LPS)

Question 25

The deletion of MURR-1 gene causes what type of disease?

Which dog breed is this derangement seen?

Answer 25

Cu-storage disease that can induce hepatocyte necrosis.

Bedlington terriers.

Question 26

Cell response to injury depends on 3 criteria:

Answer 26

Type of injury
Duration
Severity

Question 27

Consequences depend on blank, blank, blank, and blank do the injured cell.

Answer 27

Type
Status
Adaptability
Genetic makeup

Question 28

For cell injury, the cells are either: 
1) 
2)
3)
4) 
That affect essential cellular constituents.

Answer 28

1) Exposed to persistent stress beyond the limits of adaptive responses.
2) Exposed to injurious stimuli.
3) Deprived of essential nutrients.
4) Compromised by mutations.

Question 29

What are the 4 interrelated cell systems that are particularly vulnerable to injury?

Answer 29

1) Membranes (cellular and organellular).
2) Aerobic respiration.
3) Protein synthesis (enzymes, structural proteins, etc.).
4) Genetic apparatus (eg DNA, RNA)