KIN 103 Midterm (Lecture 6-7)

Question 1

Thermogenesis (Definition)

Answer 1

Temperature regulation is related to metabolic heat production

Question 2

Human body temperature (What is our average range?)

Answer 2

Body temperature is maintained within a
narrow range.
 Average = 37°C.
 Range = 35.5°C to 37.7°C

Question 3

Sources of heat input

Answer 3

• radiant energy
• conductive energy
• metabolism
• muscle contraction

Question 4

Sources of heat loss

Answer 4

• Radiant (most heat loss)
  ▫Given off by anything warmer than zero.
• Conductive
  ▫Heat lost when touching cooler object.
• Convection
  ▫Air currents resulting from temperature differences.
• Evaporation
  ▫Heat lost from water evaporation at the skin or lungs.

Question 5

What controls body temperature?

Answer 5

• Autonomic control of body temperature is
  controlled by the hypothalamus.
  ▫ Thermoregulatory centers.

Question 6

Thermoreceptors (Where are they found?)

Answer 6

• Thermoreceptors monitor changes in
  body temperature and send the sensory
  information to the thermoregulatory
  centers.
  ▫ Hypothalamus.
  ▫ Skin.

Question 7

Mechanisms To Regulate Body Temperature (What are the 4?)

Answer 7

Mechanisms To Regulate Body Temperature:
1. Adjusting Blood Flow Distribution.
2. Sweating.
3. Increasing metabolic activity.
4. Hormonal Regulation.

Question 8

Cutaneous blood vessels (What do they do?)

Answer 8

• Cutaneous blood vessel can either:
  ▫ Gain heat from the environment.
  ▫ Lose heat to the surrounding air.

Question 9

What happens if core temperature decreases?

Answer 9

• the hypothalamus activates sympathetic adrenergic neurons innervating the cutaneous blood vessels.
• Vasoconstriction of the cutaneous
  blood vessels.

Question 10

What happens if core temperature increases?

Answer 10

• Sympathetic cholinergic neurons are stimulated
  
  • This causes sweating or vasoconstriction
    to send blood to the skin

Question 11

Hormonal thermoregulation (What happens?)

Answer 11

Hormonal Regulation
* Increased release of epinephrine and
norepinephrine can increase heat
production during cold exposure.
* When cold exposure is prolonged the
thyroid gland releases more thyroxine
to elevate resting metabolic rate (RMR).

Question 12

Acclimatization (Definition)

Answer 12

Acclimatization: Living in the hot environment

Question 13

Acclimation (Definition)

Answer 13

Acclimation: Simulating the hot
environment

Question 14

Vasopressin does what in thermoregulation?

Answer 14

Vasopressin (a.k.a. Antidiuretic Hormone)
▫ Increases water reabsorption in the renal tubules.

Question 15

Aldosterone does what in thermoregulation?

Answer 15

Aldosterone (Sodium reobsorbtion)
▫ Increases reabsorption of sodium in the renal tubules reduces involuntary sodium loss.
▫ This also results in more dilute sweat (reduces the osmolarity of sweat) an feature of acclimatization.
▫ In cases of severe dehydration the Aldosterone response could become inhibited.

Question 16

What is the most we can sweat in an hour?

Answer 16

Sweat loss peaks at approximately
3 liters/hour during intense exercise in
the heat.

Question 17

Dehydration (Effects on the body?)

Answer 17

Dehydration
* When sweating leads to dehydration a number of consequences can result:
▫ Reduced plasma volume.
▫ Increased heart rate.
▫ Reduced rate of sweating.
▫ Impaired thermoregulation.
▫ Increased fatigue.
▫ Reduced performance.

Question 18

What happens to cardiac output in hot environments?

Answer 18

• Its max is reduced
• it must be shared with thermoregulatory responses alongside muscles

Question 19

The Fick equation (Equation)

Answer 19

VO2 = Q x (a – v)O2 difference

Question 20

10 METs is equal to?

Answer 20

10 METS = 35.0 ml/kg/min
- those who can do 10 METs are said to have low risk of death due to cardiovascular diseases