homestasis

Question 1

homeostasis

Answer 1

there is a narrow range of physical and biochemical conditions under which the body functions optimally

Question 2

name the 4 conditions

Answer 2

• chemical constitution
  such as glucose and ion levels
  -osmotic pressure
  relative amounts of water and solutes
  -CO2 levels
  -temperature

Question 3

definition of homeostasis

Answer 3

maintenance of a stable but dynamic (within set parameters) , physiological state by auto-regulatory processes of the body

Question 4

why most cells of large animals have no contact with the external environment?

Answer 4

-their needs are met by a wholly internal environment
-cells bathed in fluid; absorbs waste,

Question 5

how is homeostasis controlled

Answer 5

it is controlled by negative feedback

Question 6

name the 4 things that liver can do

Answer 6

glucose is used
1. cell respiration -> water and carbon dioxide
2. convert -> glycogen -> stored
3.convert -> fat and fat deposits
4. pass - > general circulation

each of these reactions happens depending on the level of blood glucose and is controlled by hormones

Question 7

cells needs to be kept between what temp?

Answer 7

0 to 40 degree C

Question 8

not all biochemical reactions change at the same rate with temperature.
True or false?

Answer 8

True

Question 9

animals get their heat from?

Answer 9

the sun solar energy
chemical energy from cell respiration

Question 10

describe ectothermic animals

Answer 10

gain heat from the environment
- all animals expect birds and mammals

Question 11

describe endothermic animals

Answer 11

-generate heat within the body
birds and mammals

Question 12

requirement of ectothermic animals

Answer 12

• require less food
  -have lower metabolic rate
• do not use energy to maintain body temperature
  -have no mechanism for conserving heat
  -use behavioural means to control body temperature
  -only active when the weather is warm enough

Question 13

endothermic animals

Answer 13

-require large quantity of food
-have a high metabolic rate
-use energy to maintain body temperature
-have mechanisms for conserving heat
- use behavioural and physiological meant control body temperatures
can remain active day and night, winter and summer

Question 14

describe aquatic animals (ecto)

Answer 14

-water temperature doesn’t fluctuate much
-body temperature is the same as the water temperature
-not all fish behave like ectotherms e.g. hot fish

Question 15

describe land animals

Answer 15

-air temperature quite variable
-gain heat from sunlight and the ground so can be more active than aquatic animals
-warming
change orientation to the sun , basking
-cooling
seek shade, follow in water, open mouths

Question 16

endotherms can respond to temperature change by changing their what?

Answer 16

metabolic rate

Question 17

in the therm-neutral zone the metabolic rate is ?

Answer 17

low and independent of temperature

Question 18

the basal metabolic rate BMR is the?

Answer 18

metabolic rate of a resting animal in the thermoneutral zone

Question 19

what happens below the lower critical temp?

Answer 19

the animal produces metabolic heat to compensate for increased heat loss to the environment

Question 20

what happens above the upper critical temp?

Answer 20

the animal must expend energy to lose heat by panting or sweating, which makes its metabolic rate increase

Question 21

what happens to metabolic rate at cooling

Answer 21

decreased metabolic rate
vasodilation

Question 22

what happens to metabolic rate at warming

Answer 22

increased metabolic rate
Vasoconstriction

Question 23

describe vasoconstriction

Answer 23

blood flow directed away from the skin

Question 24

describe vasodilation

Answer 24

increased blood flow to the skin surface