Flashcards in Topics A50-52 Environmental Causes of Disease: Tobacco, Pollution, Alcohol, Radiation Deck (40)
How do you rank the different degrees of burns?
Partial thickness: 1 and 2
-1st degree: only epidermis
-2nd degree: epidermis + superficial dermis. May have blisters.
Full thickness: 3 and 4
-3rd degree: extends through entire dermis. Stiff, white to brown. Painless at site of burn.
-4th degree: goes even deeper, appears black (eschar).
What are 3 major risks to life from burns / fires?
1. Hypovolemic shock: fluids move to interstitial area and much fluid is lost
2. Infection due to lost protection of skin (Pseudomonas especially)
3. Inhalation injury: life-threatening pulmonary edema often develops within 24-48 hours of exposure after being in burning building
What are the 3 types of hyperthermia?
1. Heat cramps: caused by electrolyte loss from sweating, usually occurs during exercise. Muscles cramp.
2. Heat exhaustion: most common type. Person collapses from hypovolemia due to sweating. Usually after fainting and rest, they recover fine
3. Heat stroke: life-threatening, uncompensated rise in core body temperature. High temperature with high humidity means sweating is ineffective and even stops. Have generalized peripheral vasodilation, arrhythmias, maybe DIC.
At around what hypothermic body temperature does loss of consciousness occur, along with what other serious symptoms of hypothermia?
Around or below 32C / 90F.
Als see bradycardia, atrial fibrillation.
What are the 2 mechanisms of injury for electrical injury?
1. Burns: require longer exposure to electrical source
2. Normal electrical impulses are disrupted: major risk is ventricular fibrillation, but can also paralyze respiratory muscles
What are the 3 forms of ionizing radiation?
1. X and γ rays: high frequency EM radiation. These are "indirectly" ionizing because they react with H2O first to make ROS. (α/β radiation is directly ionizing)
2. α particles: 2 protons and 2 neutrons, steal electrons to stabilize themselves. Most harmful one but it's easily blocked, has short range. Dangerous to ingest.
3. β particles: either high-energy electron or positron emission. Positrons can cause γ rays to be released.
Grays: energy absorbed by target tissue. Joules/kg
Sieverts: "equivalent dose" - basically the energy absorbed multiplied by the relative biologic "effectiveness" of the radiation
Which tissues are most susceptible to mutagenic/carcinogenic effects of radiation?
Cells that divide rapidly:
Most sensitive is bone marrow. Most frequent ionizing radiation problems are acute or chronic myeloid leukemias
Next most affected are breast, lung, salivary glands
(Skin, bone, GI tract are not affected much)
What is the most important intracellular target of ionizing radiation? What are some ways that it can be damaged?
Can cause base damage, single and double-stranded breaks, and cross-links between DNA and proteins. Double-stranded break is most dangerous