Skin Anatomy and Burn Pathophysiology Practice Questions

25 multiple-choice questions on Skin anatomy and burn pathophysiology for paramedic and EMT students, from Chapter 33 (Burns). Read each question, pick your answer, then tap Show answer to check it and read the explanation.

25 practice questions

1. A man has a deep partial-thickness burn on his forearm from a workshop fire. Which history question is especially important to include in your report?

   1. A. How many burns he has had before
   2. B. His blood type in case of transfusion
   3. C. What color his clothing was
   4. D. When he last had a tetanus shot
   Show answer

   Answer: D. When he last had a tetanus shot

   Burns break the skin barrier and leave dead tissue, so partial- and full-thickness burns are tetanus-prone wounds and immunization status guides hospital care. Past burns, blood type (which the hospital determines if needed), and clothing color do not change early management.

2. A superficial partial-thickness burn can usually heal without a skin graft mainly because:

   1. A. Surviving follicles and glands regrow skin
   2. B. The whole dermis is destroyed and replaced
   3. C. Scar tissue fills the wound within one day
   4. D. The fat layer below grows a new epidermis
   Show answer

   Answer: A. Surviving follicles and glands regrow skin

   In partial-thickness burns, epithelial cells lining the surviving hair follicles and sweat glands in the dermis migrate out and resurface the wound. In full-thickness burns these dermal structures are destroyed, so grafting is usually needed. The dermis is not entirely destroyed in partial-thickness burns, scar does not form in a day, and fat cannot form epidermis.

3. Which function of intact skin is most directly lost when a large area is burned, leading to hypothermia?

   1. A. Vitamin D synthesis
   2. B. Sensation of touch
   3. C. Heat regulation
   4. D. Protein storage
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   Answer: C. Heat regulation

   Burned skin cannot limit evaporative and radiant heat loss. Sensation is also lost in deep burns, but it is the loss of thermoregulation that causes hypothermia.

4. The skin is thinnest over the:

   1. A. Palms
   2. B. Eyelids
   3. C. Upper back
   4. D. Soles of the feet
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   Answer: B. Eyelids

   Thin skin burns deeply at lower temperatures or shorter exposures. The palms and soles have thick skin and tolerate brief heat better.

5. In the first hours after a 50% TBSA burn, a patient's cardiac output falls. The main reason is:

   1. A. Blood loss from the burned skin surface
   2. B. A slow heart rate caused by burn pain
   3. C. Increased venous return from the edema
   4. D. Plasma loss plus circulating mediators
   Show answer

   Answer: D. Plasma loss plus circulating mediators

   Massive capillary leak removes plasma from the circulation, lowering preload, and inflammatory mediators also depress the heart and raise vascular resistance, so cardiac output falls early. Burns themselves bleed little, pain causes tachycardia rather than bradycardia, and edema reduces rather than increases venous return.

6. In an adult, a body-wide capillary leak and burn shock requiring formal fluid resuscitation are generally expected once partial- and full-thickness burns exceed about:

   1. A. 20% TBSA
   2. B. 5% TBSA
   3. C. 50% TBSA
   4. D. 1% TBSA
   Show answer

   Answer: A. 20% TBSA

   Below roughly 15 to 20% TBSA, the inflammatory response is mostly local. Above about 20% in adults (10 to 15% in children), mediators cause a systemic capillary leak, and ABLS recommends formal fluid resuscitation. 1% and 5% burns rarely cause shock, and waiting for 50% would greatly undertreat patients.

7. The outer zone of a burn wound, which has increased blood flow and usually recovers within about a week, is the zone of:

   1. A. Stasis
   2. B. Hyperemia
   3. C. Coagulation
   4. D. Eschar
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   Answer: B. Hyperemia

   Inflammatory vasodilation makes this outer zone red. Stasis is the middle zone at risk of progression, not the outer zone that heals.

8. Burn shock develops mainly because:

   1. A. Blood is lost from the surface of the burned skin
   2. B. The heart muscle is directly damaged by heat
   3. C. Capillaries leak fluid and protein into tissues
   4. D. Spinal cord injury causes widespread vasodilation
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   Answer: C. Capillaries leak fluid and protein into tissues

   Inflammatory mediators make capillaries leaky throughout the body, so plasma shifts into the interstitium. Burns rarely bleed, so blood loss is not the mechanism.

9. The capillary leak after a major burn is greatest during the first:

   1. A. 24 hours
   2. B. 2 hours
   3. C. 72 hours
   4. D. 7 days
   Show answer

   Answer: A. 24 hours

   Fluid shift is most intense in the first 8 to 24 hours, which is why resuscitation front-loads fluid. It does not peak within 2 hours, so early shock suggests another cause.

10. A 40-year-old man with 35% TBSA flame burns is pale, with a pulse of 136 and a BP of 78/50 mmHg, 15 minutes after the fire. The most likely explanation is:

    1. A. Burn shock from capillary leak
    2. B. Another injury causing bleeding
    3. C. Carbon monoxide causing vasodilation
    4. D. Pain-induced neurogenic shock
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    Answer: B. Another injury causing bleeding

    Burn shock takes hours to develop. Early hypotension in a burned patient should prompt a search for trauma such as a fall, blast, or crash, rather than being blamed on the burn.

11. A man with 40% TBSA burns of the trunk and arms develops swelling of his unburned face and legs several hours later. This occurs because:

    1. A. Lymph vessels are destroyed by heat
    2. B. Kidneys stop filtering sodium
    3. C. IV fluids are given too quickly
    4. D. Mediators cause leak body-wide
    Show answer

    Answer: D. Mediators cause leak body-wide

    Large burns release inflammatory mediators into the circulation, so capillaries leak everywhere and even unburned areas swell. Heat does not destroy lymph vessels in unburned tissue. The kidneys keep filtering sodium; renal failure is not the cause of early edema. Over-resuscitation worsens edema but does not explain it on its own.

12. A 30-year-old woman with 40% TBSA burns has a hematocrit of 55% six hours after injury. The most likely cause is:

    1. A. Bleeding from the burn wound
    2. B. Red cell production by the marrow
    3. C. Plasma loss into the tissues
    4. D. Heat-induced hemolysis
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    Answer: C. Plasma loss into the tissues

    Plasma leaves the vessels while red cells stay behind, so hematocrit rises. Heat does destroy some red cells, but that would lower, not raise, the hematocrit.

13. A 45-year-old man with deep flame burns and crushed muscle develops peaked T waves on the monitor. The most likely cause is:

    1. A. Loss of potassium through the urine
    2. B. Excess sodium in the IV fluids
    3. C. Potassium from damaged cells
    4. D. Alkalosis from fast breathing
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    Answer: C. Potassium from damaged cells

    Destroyed cells and muscle spill potassium into the blood. Renal potassium loss would cause hypokalemia, the opposite problem.

14. A steam burn of the skin tends to be deeper than a hot-water scald of the same temperature mainly because steam:

    1. A. Releases extra heat as it condenses
    2. B. Conducts heat better than liquid water
    3. C. Sticks to the skin like hot grease
    4. D. Is under pressure that drives heat in
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    Answer: A. Releases extra heat as it condenses

    When steam condenses on the skin, it gives up its latent heat of vaporization in addition to its temperature, delivering much more energy than water at the same temperature. A gas actually conducts heat less well than liquid water, steam does not stick like grease, and it is not pressure that drives the heat into the skin.

15. Hard, leathery, dead tissue that forms over a full-thickness burn is called:

    1. A. Granulation
    2. B. Eschar
    3. C. Keloid
    4. D. Bulla
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    Answer: B. Eschar

    Eschar is inelastic, so a circumferential band can constrict breathing or blood flow. A bulla is a blister, seen in partial-thickness burns.

16. A 40-year-old man has survived the first week after 50% TBSA burns. The greatest threat to his life now is:

    1. A. Burn shock from capillary leak
    2. B. Upper airway swelling
    3. C. Acute hyperkalemia
    4. D. Infection and sepsis
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    Answer: D. Infection and sepsis

    Loss of the skin barrier and immune suppression allow infection. Burn shock and airway swelling kill early, not after the first few days.

17. Adult skin exposed to water at 60°C (140°F) can develop a full-thickness burn in about:

    1. A. 5 seconds
    2. B. 5 minutes
    3. C. 30 minutes
    4. D. 1 hour
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    Answer: A. 5 seconds

    Damage rises steeply with temperature. Water near 49°C (120°F) takes minutes to cause a deep burn, but at 60°C it takes only seconds.

18. Water heaters are recommended to be set no higher than 49°C (120°F) because:

    1. A. Bacteria cannot grow above that point
    2. B. Pipes are damaged at higher settings
    3. C. Burns at that level are always superficial
    4. D. Scalds at that temperature take minutes
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    Answer: D. Scalds at that temperature take minutes

    At 49°C a deep scald takes several minutes, giving time to escape. Burns can still be deep with long contact, as in an immobile older adult, so they are not always superficial.

19. After a major burn, the body's metabolic rate:

    1. A. Falls to conserve energy
    2. B. Rises for weeks to months
    3. C. Stays the same as before
    4. D. Rises only for the first hour
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    Answer: B. Rises for weeks to months

    Burns cause a prolonged hypermetabolic state with high calorie needs and muscle wasting. It is not a brief or falling response.

20. A 30-year-old woman with 50% TBSA burns becomes progressively less responsive during a long transport. Her skin is cool, and her temperature is 34.8°C (94.6°F). Which mechanism best explains the temperature?

    1. A. Fever from an early wound infection
    2. B. Cyanide toxicity from the smoke
    3. C. Loss of skin barrier to heat loss
    4. D. Excess warm IV fluid during transport
    Show answer

    Answer: C. Loss of skin barrier to heat loss

    Burned skin cannot retain heat, so large burns become hypothermic quickly. Infection causes fever, not a low temperature, and appears days later.

21. The depth of a thermal burn depends mainly on:

    1. A. Fuel type, flame color, and smoke density
    2. B. Patient age, sex, and body weight
    3. C. Heat, contact time, and skin thickness
    4. D. Burn location, shape, and pain level
    Show answer

    Answer: C. Heat, contact time, and skin thickness

    Heat damage rises with temperature and duration of contact and is deeper where skin is thin. Location matters for severity and referral, but it does not by itself determine how deep the burn goes.

22. A 79-year-old woman was found on the floor next to a space heater after lying there for hours. Compared with a younger adult, her burn is likely to be:

    1. A. Shallower, due to reduced blood flow
    2. B. Deeper, because her skin is thinner
    3. C. Identical, since depth depends only on heat
    4. D. Superficial, because heaters are cool
    Show answer

    Answer: B. Deeper, because her skin is thinner

    Older adults have thinner dermis and longer contact times from immobility, so burns are deeper. Depth depends on heat, time, and skin thickness, not heat alone.

23. Two hours after a 40% TBSA burn, a patient becomes nauseated, vomits, and asks for a drink. The best approach is to:

    1. A. Keep her NPO and protect the airway
    2. B. Give large amounts of water by mouth
    3. C. Lay her flat on her back to rest
    4. D. Give an oral sports drink to replace salt
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    Answer: A. Keep her NPO and protect the airway

    Major burns reduce gut blood flow and commonly cause ileus with nausea and vomiting, so patients with large burns are kept NPO, positioned to protect the airway, and resuscitated IV. Oral fluids are not absorbed reliably and raise aspiration risk, and supine positioning without airway protection is unsafe in a vomiting patient.

24. A conscious adult with 45% TBSA burns is hypotensive 4 hours after injury with no other injuries. The treatment that best addresses the cause is:

    1. A. Packed red blood cells
    2. B. A vasopressor infusion started first
    3. C. Oral fluids as tolerated en route
    4. D. Isotonic crystalloid infusion
    Show answer

    Answer: D. Isotonic crystalloid infusion

    By 4 hours, burn shock from plasma loss is expected and is treated with crystalloid, usually lactated Ringer's. Blood is not lost, so red cells are not the primary need.

25. Which statement about the skin's role in fluid balance is correct?

    1. A. Sweat is the body's main water loss route
    2. B. Burned skin seals in water as it dries
    3. C. Burned skin loses less water than normal
    4. D. Intact skin limits water loss
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    Answer: D. Intact skin limits water loss

    Burned skin can lose many times more water by evaporation than intact skin. It does not lose less or seal in water as it dries, which is why large burns become dehydrated. Kidneys, not sweat, account for most daily water loss in a resting person.