33. Thermoregulation: responses and adaptations to heat

Question 1

how does the hypothalamus respond when theres a rise in core temperature? 3 steps

Answer 1

1. vasodilation
2. sweat glands activated
3. fall in core temperature

Question 2

how does the hypothalmus respond to a fall in core temperature? 3 steps

Answer 2

1. vasoconstriction
2. skeletal muscles activated
3. rise in core temperature

Question 3

what are the four ways an mammal gains and looses heat with the thermal environment?

Answer 3

• conduction
• convention
• radiation
• evaportion

Question 4

what is radiation?

Answer 4

the transfer of heat by electromagnetic radiation - without direct conatct with objects

Question 5

what is conduction?

Answer 5

the transfer of heat between objects with direct contact with each other

Question 6

what is convection?

Answer 6

a specialised for of conduction - the transfer of heat contined in gas or liquid

Question 7

what is evaportation?

Answer 7

the energy required to change a liquid to a gas

Question 8

what are the three ways of rate of heat transfer as mechanims for temperature control?

Answer 8

1. surface area - the size of the animal of how much heat they transfer
2. temperature differences - altering the temperature gradient
3. specific heat conductance - eg fur trapping air and conducts heat, blubber is low at conducting heat

Question 9

what is perpheral heterthermy?

Answer 9

localised changes in heat.

the core is more closely controlled nad variation in the ‘shell’ is peripheral heterthermy

Question 10

what is the thermonetural zone?

Answer 10

where body temperature is mainated without changing the BMR, so no energy expenditure

Question 11

what are four features that alter body temperature?

Answer 11

1. smooth muscle around artioles
2. sweat gland
3. skeletal muscle
4. endocrine glands

Question 12

what are four temperature decreasing mechanisms?

Answer 12

1. vasodilation
2. sweating
3. decrease in heat production
4. behavioural thermoregulation

Question 13

what is vasodilation and how does it decrease temperature?

Answer 13

letting muscles relax and widening of arteries = higher blood flow. lots of blood to periphery which menas heat can be lost

Question 14

what is a sweat gland and how does it reduce tempertaure?

Answer 14

an exocrine gland that produces sweat. eccrine gland produces the sweat. evaportation of sweat allows cooling

Question 15

what are three examples of behaviroual mechanisms to decrease body temperature? not in the thermoneutral zone

Answer 15

1. panting
2. taking off clothes
3. seeking shade
4. going near water

Question 16

how does the hypothalamus act as a mammals thermostat?

Answer 16

neuron sin the preoptic area generate a nerve impule at a high frequency which temp increases

low frequency when body temp decreases

Question 17

how have different species of animals evolved to deal with heat?

Answer 17

to deal with the limiting water availability

evaporation to remove excess heat

Question 18

why is opening and closing of blood vessels important for thermoregulation?

Answer 18

the concentration gradient helps be more effiecent

Question 19

what is the lower and upper critical temperature?

Answer 19

lower - body is colder than the external environemnt

upper - body is hotter than the external envionrment (evaportaion)

both use energy to thermoregulate

Question 20

which zone does panting come into place and why?

Answer 20

in the upper crtiical zone because it is using evaporation to reduce heat and is above the BMR due to moving the diaphram