Mangiarua - Themroregulation

Question 1

Two factors that almost entirely determine the rate of heat loss:

Answer 1

How rapidly heat is conducted from where it is produced in the body core to the skin

How rapidly heat is transferred from skin to the surrounds.

Question 2

Rate of blood flow in the skin is controlled by ?

Answer 2

Degree of vasoconstriction of the arterioles and arteriovenous anastomoses —>sympathetic nervous system

Question 3

Loss of heat.
From infrared heat rays (electromagnetic waves)

All directions.

Varies directly w/ the difference between body temp and temp of surroundings

Answer 3

Radiation

Question 4

Heat transfer between surfaces in contact.

To objects is low %

To air is a sizeable portion of heat loss

Answer 4

Conduction

Question 5

Transfer of heat by the actual movement of warm air

Answer 5

Convection

Question 6

The amount of fluid lost on a daily basis from the lungs, skin, and respiratory tract, as well as water excreted in the feces

Answer 6

Insensible water loss

Question 7

When skin temp is greater than ambient temp, heat loss comes from ____

Answer 7

Radiation and conduction

Question 8

When ambient temp is greater than that of skin, heat loss is only by

Answer 8

Evaporation

Question 9

Stimulation of the anterior hypothalamus-preoptic area causes _____ for thermal regulation

Answer 9

Sweating

Question 10

Where are the deep body temperature receptors located?

Answer 10

Spinal cord

Abdominal viscera

In or around the great veins in the upper abdomen and thorax

Question 11

Temperature - decreasing mechanisms when the posterior hypothalamus is told that it is too hot

Answer 11

Skin vasodilation

Sweating

Decreased heat production

Behavioral response (find shade)

Question 12

Proteins, breakdown products of proteins, lipopolysaccharide toxins

Cause the hypothalamic set point to rise

Answer 12

Pyrogens

Question 13

Develop when body temperature rises beyond 105-108

S/s ; dizziness, abd distress, vomiting, delirium, LOC, circulatory shock 2nd to loss of fluid and electrolytes in sweat

Answer 13

Heatstroke

Question 14

Occurs after excessive loss of salt and water due to sweating, and/or when venous return is compromised by heavy exertion and maximal cutaneous vasodilation. Body temp may remain w/in normal values

Answer 14

Heat exhaustion

Question 15

Results in a generally slowing of metabolism and of cardiac and neuronal excitability

Body temp about 94 - thermoregulation impaired

Body temp below 85F - thermoregulation lost

Body temp below 77 (exposure to ice water for 20-30 minutes) death, due to heart standstill/fibrillation

Answer 15

Hypothermia

Question 16

Body surface areas freeze when exposed to extremely low temperatures

Esp. In the hands, feet and earlobes

Answer 16

Frostbite

Question 17

Acclimatization to cold :

Answer 17

Increased chemical thermogenesis by elevated catecholamine and thyroxine levels