Chapter 10: Thermoregulation

Question 1

Thermoregulation

Answer 1

Maintenance of fairly constant tissue temperature

Question 2

5 types of thermoregulation

Answer 2

1. Insulation
2. Cooling by evaporation
3. Circulatory adaptation
4. Heat loss
5. Regulating Environmental ?

Question 3

Regional Heterothermia

Answer 3

Body core stays at a regulatory temp while limbs are set closer to ambient temps

Question 4

Heat

Answer 4

A form of energy that a substance possesses by virtue of the random motions of its atomic and molecular constituents

Question 5

Temperature

Answer 5

The speed (or intensity) of the random motions of atoms and molecules

Question 6

Important temperatures (*C):

• Boiling point (H2O)
• Body temp
• Room temp
• Freezing point (H2O)
• Absolute zero

Answer 6

• Boiling point (H2O) = 100 *C
  
  • Body temp = 37 *C
  • Room temp = ~20 *C
  • Freezing point (H2O) = 0 *C
  • Absolute zero = -273 *C or 0 *K

Question 7

Endothermy

Answer 7

When an animal’s tissues are warmed by its metabolic production of heat

Question 8

Ectotherms

Answer 8

Body temp is the same as the environment’s temp

Question 9

Poikilotherms

Answer 9

Variable body temp close to the environment’s temp

Question 10

Endotherms

Answer 10

Can produce metabolic heat

Question 11

Homeotherms

Answer 11

Thermoregulated by physiological heat

Question 12

Heterothermy

Answer 12

A difference in thermal relations from one time to another (temporal) or one body region to another within a single individual (regional)

Question 13

Eurythermal

Answer 13

Can exist in a high range of temps

Question 14

Stenothermal

Answer 14

Can only exist in narrow temp ranges

Question 15

3 tissue processes that are effected by temperature

Answer 15

• Metabolic rates
• Rates of biochemical reactions (enzymes)
• Rates of biophysical processes (diffusion and osmosis)

Question 16

Hypothalamus

Answer 16

The thermoregulatory control center in the brain

Question 17

Thermoneutral zone (TNZ)

Answer 17

A range of ambient temperatures which is the resting metabolic rate

Question 18

2 Modulations of insulation

Answer 18

• Pilomotor response (hair)

- Vasomotor response (blood vessels)

Question 19

2 types of heat production

Answer 19

• Shivering

- Nonshivering thermogenesis

Question 20

Shivering

Answer 20

Unsynchronized contraction and relaxation of skeletal muscle motor units in high-frequency rhythms

Question 21

Nonshivering thermogenesis

Answer 21

• Involves brown adipose tissue
• Receives a rich supply of blood vessels
• Contains great numbers of large mitochondria
• Releases Norepi in the brown adipose tissue
• Tissue increases oxidation of its stored lipids to increase heat production

Question 22

Uncoupling protein 1 (UCP 1)

Answer 22

Prevents ATP from forming causing the brown adipose tissue to release heat

Question 23

Countercurrent heat exchange

Answer 23

Arteries are set close together in the appendages so heat short-circuiting from arterial blood into venous blood and is not lost into the environment

Question 24

Sweating

Answer 24

Fluid secreted by way of sweat gland ducts in skin (activated by the sympathetic nervous system)

Question 25

Panting

Answer 25

Increase in breathing rate in response to heat stress

Question 26

Evaporative cooling

Answer 26

The ultimate line of defense for mammals faced with high environmental or metabolic heat loads