Chapter 33 - Environmental Emergencies

Question 1

Identify the four factors that affect how a person deals with exposure to a cold or hot environment.

Answer 1

1) Physical condition
2) Age
3) Nutrition and hydration
4) Environmental conditions

Question 2

homeostatis

Answer 2

when all systems in the human body operates in balance

Question 3

How does the body normally balance heat production and elimination?

Question 4

What factors can decrease the body’s ability to eliminate excess heat?

Question 5

thermoregulation

Answer 5

the body’s ability to maintain normal temperature

Question 6

How does an infant’s body differs from others in regards to thermoregulation?

Answer 6

Infants have poor thermoregulation at birth and do not have the ability to shiver and generate heat when needed until about 12 to 18 months. An infant’s surface area-to-mass ratio is larger than and adult’s, so infants heat up and cool down faster.

Question 7

How does and older person’s body differs from younger adults’ and why?

Answer 7

Older adults have a loss of subcutaneous tissues as they age, reducing the amount of insulation they have. Poor circulation also contributes to the increased heat loss. Medications can also affect an older person’s body thermostat. Older patients are also at a high risk for falls, and lying immobile on a hot or cold surface can rapidly lead to overexposure.

Question 8

Normal body temperature is

Answer 8

98°F (36.7°C)

Question 9

ambient temperature

Answer 9

the temperature of the surrounding environment

Question 10

Heat loss can occur in the following ways:

Answer 10

Conduction
Convection
Evaporation
Radiation
Respiration

Question 11

Conduction is

Answer 11

the transfer of heat from a part of the body to a colder object or substances by direct contact, such as when a warm hand touches cold metal or ice, or is immersed in water with a temperature of less than 98°F (36.7°C). Heat can also be gained if the object or substance being touched is warm.

Question 12

Convection occurs when

Answer 12

heat is transferred to circulating air, such as when cool air moves across the body surface.

Question 13

Evaporation is the

Answer 13

conversion of any liquid to a gas, a process that requires energy, or heat. Evaporation is the natural mechanism by which sweating cools the body.

Question 14

Radiation is the

Answer 14

transfer of heat by radiant energy. Radiant energy is a type of invisible light that transfers heat. Radiation causes heat loss, such as when a person stands in a cold room. Heat can also be gained by radiation - for example, when a person stands by a fire.

Question 15

Respiration causes

Answer 15

body heat loss as warm air in the lungs is exhaled into the atmosphere and cooler air is inhaled. In warm climates, the air temperature can be well above the body temperature, causing an individual to gain heat with each breath.

Question 16

What are the three ways the rate and amount of heat loss or gain by the body can be modified?

Answer 16

1) Increase or decrease heat production
2) Move to an area where heat loss is decreased or increased
3) Wear the appropriate clothing for the environment

Question 17

Shivering

Answer 17

One way for the body to increase its heat production is to increase the rate of metabolism of its cells’; the body can accomplish this through shivering (active movement of many muscles to generate heat).

Question 18

hypothermia

Answer 18

When the entire body temperature falls, the condition is called hypothermia (low temperature). It is diagnosed when the core temperature of the body - temperature of the heart, lungs, and vital organs- falls below 95°F (35°C). The body can usually tolerate a drop in core temperature of a few degrees. However, below this critical point, the body cannot regulate its temperature and generate body heat. Progressive loss of body heat then begins.
To protect itself against heat loss, the body normally constricts blood vessels in the skin; this results in the characteristic appearance of blue lips and/or fingertips. As a secondary precaution against heat loss, the body tends to create additional heat by shivering. As cold exposure worsens and these mechanisms are overwhelmed, many body functions begin to slow down and mental status deteriorates. Eventually, the functioning of key organs such as the heart begins to slow. Untreated, this can lead to death.