Temperature Regulation

2.

The heat transfer mechanism that occurs between arteries and veins in a countercurrent exchange is called what?

Conduction
Convection
Radiation
Evaporation

Correct Answer

A. Convection

Explanation

Convection is the heat transfer mechanism that occurs between arteries and veins in a countercurrent exchange. In this process, heat is transferred through the movement of a fluid, such as blood, which carries the heat from the arteries to the veins. This allows for efficient heat exchange and helps to maintain body temperature. Conduction, radiation, and evaporation are not the correct answers because they do not involve the movement of a fluid.

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3.

What is the major heat source to retain body temperature for a nude 65-kg adult person in a 29^oC/84.2^oF environment?

Brain
Brown adipose tissue
Liver
Skeletal muscle
White adipose tissue

Correct Answer

A. Skeletal muscle

Explanation

Skeletal muscle is the major heat source to retain body temperature for a nude 65-kg adult person in a 29oC/84.2oF environment. Skeletal muscle generates heat through contractions and is responsible for shivering, which helps to generate heat and maintain body temperature. Unlike other tissues listed, skeletal muscle has a high metabolic rate and can produce significant amounts of heat, making it the primary heat source in this scenario.

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4.

Which of the following is a human thermoregulatory response controlled by cholinergic sympathetics?

Brown adipose tissue thermogenesis
Hand vasomotion
Shivering thermogenesis
Sweat secretion
Thermoregulatory behavior

Correct Answer

A. Sweat secretion

Explanation

Sweat secretion is a human thermoregulatory response controlled by cholinergic sympathetics. When the body temperature rises, the cholinergic sympathetic nerves stimulate the sweat glands to produce sweat. This helps to cool down the body as the sweat evaporates from the skin surface, leading to heat loss.

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5.

Which of the following will most faithfully reflect changes in human core temperature that could be caused by immersion in a warm body bath?

Oral temperature
Rectal temperature
Axillary temperature
Tympanic temperature
Esophageal temperature at the cardia

Correct Answer

A. Esophageal temperature at the cardia

Explanation

The esophageal temperature at the cardia is the most accurate reflection of changes in human core temperature caused by immersion in a warm body bath. This is because the esophagus is located in close proximity to the core of the body, allowing for more accurate measurement of core temperature. Oral, axillary, and tympanic temperatures may be influenced by external factors and may not accurately reflect core temperature. Rectal temperature is also closer to core temperature, but it may not be as accurate as esophageal temperature measurement.

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6.

In a man passively warmed such that his mean skin temperature reaches 40.5^oC/104.9^oF, which of the following circulatory responses will occur?

Increased cardiac output, decreased splanchnic blood flow
Increased cardiac output, increased muscle blood flow
Unchanged cardiac output, decreased right atrial pressure
Unchanged cardiac output, decreased renal blood flow

Correct Answer

A. Increased cardiac output, decreased splanchnic blood flow

Explanation

When a person is passively warmed and their mean skin temperature reaches 40.5oC/104.9oF, the body's circulatory responses will include an increased cardiac output and decreased splanchnic blood flow. The increased cardiac output is a result of the body's attempt to dissipate the excess heat by increasing blood flow to the skin, which helps in cooling down the body. At the same time, the splanchnic blood flow, which refers to the blood flow to the abdominal organs, is decreased as a way to redirect blood flow to the skin for cooling purposes. Therefore, the correct answer is increased cardiac output, decreased splanchnic blood flow.

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7.

Which of the following is true at the beginning of the rising phase of fever?

Sweat secretion is stimulated
Mean skin temperature is below normal
Muscle blood flow is decreased
Behavioral thermoregulatory responses are inhibited
Warm-sensitive neurons in the integration center are excited

Correct Answer

A. Mean skin temperature is below normal

Explanation

At the beginning of the rising phase of fever, the mean skin temperature is below normal. This is because during fever, the body's thermoregulatory set point is elevated, causing the body to conserve heat and reduce heat loss. As a result, blood vessels near the skin constrict, reducing blood flow to the skin and lowering the mean skin temperature.

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8.

The principal physical mechanism that accounts for the transfer of heat within the body is what?

Conduction
Convection
Radiation
Evaporation

Correct Answer

A. Convection

Explanation

Convection is the principal physical mechanism that accounts for the transfer of heat within the body. Convection involves the transfer of heat through the movement of fluids, such as blood or air, which carry the heat from one area to another. This process is important in maintaining the body's temperature and distributing heat throughout the body. Conduction refers to the transfer of heat through direct contact, radiation involves the transfer of heat through electromagnetic waves, and evaporation is the process of heat loss through the conversion of liquid to gas. However, in the context of the body, convection is the primary mechanism for heat transfer.

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9.

When the environmental temperature increases moderately, what happens to blood flow to the skin?

It decreases to stop the transport of heat from the skin surface to deeper tissues
It decreases because the local thermoreceptors in the skin sense an increase in body temperature
It increases because the sweat glands release vasodilators
It increases as part of the body temperature regulatory mechanisms
It increases as the metabolic needs of the skin tissue increase

Correct Answer

A. It increases as part of the body temperature regulatory mechanisms

Explanation

When the environmental temperature increases moderately, blood flow to the skin increases as part of the body temperature regulatory mechanisms. This is because increased blood flow to the skin helps dissipate heat from the body's surface to the environment, helping to cool down the body and maintain a stable internal temperature.

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10.

If someone is experiencing heat exhaustion. Which of the following would definitively indicate that they are now at risk for heat stroke?

Increased sympathetic dilation of their blood vessels
Increased hypotension
Their skin becomes very dry
They suddenly faint
They have an increased volume of sweat production

Correct Answer

A. Their skin becomes very dry

Explanation

When someone is experiencing heat exhaustion, their body is unable to cool itself properly and they may have symptoms such as heavy sweating, fatigue, and dizziness. However, if their skin becomes very dry, it is a definitive indication that they are now at risk for heat stroke. Heat stroke is a more severe condition where the body's temperature regulation system fails, and dry skin is a sign that the body is no longer able to produce sweat to cool down. This can be a life-threatening situation and immediate medical attention is required.

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Temperature Regulation

The heat transfer mechanism that occurs between the sun and the outer layer of the skin is called what?

Quiz Preview

The heat transfer mechanism that occurs between arteries and veins in a countercurrent exchange is called what?

What is the major heat source to retain body temperature for a nude 65-kg adult person in a 29^oC/84.2^oF environment?

Which of the following is a human thermoregulatory response controlled by cholinergic sympathetics?

Which of the following will most faithfully reflect changes in human core temperature that could be caused by immersion in a warm body bath?

In a man passively warmed such that his mean skin temperature reaches 40.5^oC/104.9^oF, which of the following circulatory responses will occur?

Which of the following is true at the beginning of the rising phase of fever?

The principal physical mechanism that accounts for the transfer of heat within the body is what?

When the environmental temperature increases moderately, what happens to blood flow to the skin?

If someone is experiencing heat exhaustion. Which of the following would definitively indicate that they are now at risk for heat stroke?

Temperature Regulation

The heat transfer mechanism that occurs between the sun and the outer layer of the skin is called what?

Quiz Preview

The heat transfer mechanism that occurs between arteries and veins in a countercurrent exchange is called what?

What is the major heat source to retain body temperature for a nude 65-kg adult person in a 29oC/84.2oF environment?

Which of the following is a human thermoregulatory response controlled by cholinergic sympathetics?

Which of the following will most faithfully reflect changes in human core temperature that could be caused by immersion in a warm body bath?

In a man passively warmed such that his mean skin temperature reaches 40.5oC/104.9oF, which of the following circulatory responses will occur?

Which of the following is true at the beginning of the rising phase of fever?

The principal physical mechanism that accounts for the transfer of heat within the body is what?

When the environmental temperature increases moderately, what happens to blood flow to the skin?

If someone is experiencing heat exhaustion. Which of the following would definitively indicate that they are now at risk for heat stroke?

What is the major heat source to retain body temperature for a nude 65-kg adult person in a 29^oC/84.2^oF environment?

In a man passively warmed such that his mean skin temperature reaches 40.5^oC/104.9^oF, which of the following circulatory responses will occur?