thermoregulation

Question 1

why is tempreture so important to creatures?

Answer 1

creature have a narrow range of temptreture they can function at, when ouside of their range function can stop or cells can die

Question 2

What is an ectotherm

Answer 2

Maintains heat by reacting to the external sources, their bodies can tolerate a wider range of temperature and are more energetically efficient. However when they are cold they are at higher risk of predation.

Question 3

what is an endotherm

Answer 3

animals generate heat through metabolic processes, while this uses more energy this also means that they can be more adaptive to the temperature.

Question 4

list the four ways of heat exchange occurs

Answer 4

convection, conduction, radiation, evaporation

Question 5

what is convection

Answer 5

Heat moving from an object into an external fluid. Heat transfer depends on the thermal gradient.

Question 6

what is evaporation

Answer 6

heat lost on surface through moisture evaporation

Question 7

what is radiation

Answer 7

Infrared thermal radiation, this is highly dependent on the colour

Question 7

what is conduction

Answer 7

Heat transfer through direct contact, the rate depends on the thermal gradient. (lizard and rock)

Question 8

list types of adaptation animals may have to help thermoregulation

Answer 8

fur, feathers, dense, thickness and length, types of hair. some feather have waterproof qualities. skin, thick with blubber and even colour

Question 9

how have penguins adapted to the cold

Answer 9

they have long and thick feathers that are densly packed.

Question 10

describe how polar bear have adapted

Answer 10

thick, dense and long hair for insulation. thei skin is very thick with lost of blubber in the hypodermis (FAT). and their skin in black under their skin.

Question 11

how have raindeer adapted to the cold

Answer 11

they have thick fur and the ablility to grow a winter coat for when snow arrives.

Question 12

describe the countercurrent mechanism

Answer 12

fluid flow in oppsite direction causeing heat exchange.

Question 13

describe shivering

Answer 13

involantary muscle temours (10/sec) this increases oxygen use by 400%.

Question 14

describe non shivering thermogenesis

Answer 14

• increasing hirmone regulation (adrenoline, noradrenaline, thyroxine) this increases metabolism and energy useage which increases tempreture.
• brow fat (in young) is burned quickley to increases tempreture

Question 15

describe brown fat and why it is unique

Answer 15

Brown fat has a high concentration of mitochondria, presence of cytochromes (iron makes the brown colour), the fat are in small bundles. When they are burned the energy is used directly for heating.

Question 16

describe the thermoneutral zone

Answer 16

Range of which endothermic animals can maintain temperature without altering their heat production, thus the other body temperature is equal to the core body temperature.

Question 17

descirbe the critical temptretures

Answer 17

Lower critical temperature: the minimum body temperature that can be tolerated by an organism.
Upper critical temperature: the maximum body temperature that can be tolerated by an organism.

Question 18

Describe the role and location of the sensors of thermoregulation

Answer 18

Peripheral - skin, tempreture sensative neurons which react to both hot and cold
Central - Viscera in the gastrointestinal tract, drinking cold/hot fluids stimulate these receptors.
both of these connect the the hypothalamic control centre

Question 19

list some heating mechanisims

Answer 19

Behavioral (burrows ect)
Insulation (hair)
Reduced blood flow to skin
Countercurrent exchangers
Reduces heat loss via conduction, radiation/ convection/ evaporation
Increase internal heat generation-Unique to endotherms, metabolic activity

Question 20

list some cooling mechanisims

Answer 20

Decrease insulation
Vasodilation
Increase evaporation
Avoidance behaviour
Anatomical reduction in heat gain

Question 21

what is hyperthermia

Answer 21

Hyperthermia is unregulated rise of body temperature caused by environmental conditions. Input of heat from the environment needs to exceed heat output from the body.
- 44 degrees is fatal

Question 22

what is a fever and what causes it

Answer 22

Fever is elevation of body temperature as a result from infection or inflammation. The WBC releases pyrogens which increase temperature and kill foreign pathogens. Hypothalamus now maintains that new heated temperature caused by the pyrogen until the pathogen is killed. To do this the body shivers, peripheral vasoconstriction and piloerection.

Question 23

describe how metabolism is used to heat bodies

Answer 23

Increase blood flow
Increase reactions (produces heat)
Increasing fat production to boost insulation
Constriction of blood vessels to protect vitals
Shivering
Brown fat cell usage

Question 24

describe how metabolism is used to cool bodies

Answer 24

Blood vessel dilation to radiate heat
Sweating

Question 25

how is the brain protected from tempreture in mamals

Answer 25

The rete mirabile uses the cool blood from the nose to cool the arterial blood entering the brain through countercurrent exchange..

Question 26

what is the effect of the stimulation of the piloerector muscle

Answer 26

the hair stand on end, traping radiation heat from the body, also prevent convection from the surrondings