2.4 Metabolism in Conformers and Regulators Flashcards
State some external abiotic factors that can affect an organism’s ability to maintain its metabolic rate?
Salinity, Temperature and pH
What is the definition of a ‘conformer’
An organism whose internal environment is dependent upon external environment
What is a ‘regulator’?
An organism that maintains a constant internal body environment regardless of external environment.
Give an advantage and a disadvantage of a conformer
:) Low metabolic cost, energy conservation
:( Narrow range of ecological niches, less adaptable
Describe the metabolic costs and ecological niches of a regulator
:) Occupy a wide range of niches
:( Energy costs and metabolic costs are high
What is ‘Homeostasis’
A process by which a regulator maintains a constant internal body environment regardless of external environment
What control mechanism does homeostasis use?
Negative Feedback Loops
Describe the process of negative feedback control
Receptors inside a monitoring centre monitor a factor. If it fluctuates from its set point, nerves/hormone messages are sent to effector organs, which will initiate a corrective mechanism to bring factor back to setpoint.
What is Thermoregulation?
A form of homeostasis where the body temperature is maintained at optimum
What is the optimum body temperature for a human?
37 degrees celsius
What is the temperature monitoring centre in humans?
Hypothalamus
What type of message is sent to effector organs in thermoregulation
Electrical impulses travelling along nerves
What is the response of the sweat glands if there is a increase is detected in the body temperature?
Sweat glands activated, allowing for heat loss by evaportation
What type of heat loss is caused by the sweat glands?
Evaporation
What is the response of sweat glands if a decrease is detected in body temperature?
Sweat glands close and less heat is lost by evaporation
What is the response of the hair erector muscles if a decrease is detected in body temperature?
They contract, raising the hairs on skin, trapping a layer of warm air, insulating the skin
What type of heat loss is found by heat on skin? (hair raising etc)
Radiation
Vasoconstriction is a response to _______?
A decrease in body temperature
What happens in Vasodilation?
Response to increase in body temperature
- blood vessels expand
- blood vessels move closer to surface
What happens in Vasoconstriction?
Response to decrease in body temperature
- blood vessels constrict
- blood vessels move away from surface
Why is it important to maintain body temperature?
- Enzymes have an optimum, allowing them to work at best, high metabolic rate
- Temperature affects diffusion rates, faster at warmer temps, contribute to maintenance of high metabolic activity
What happens to metabolic rate when the internal temperature of a human decreases?
It decreases as well
List the ways in which effectors respond to cold temperatures?
- Skeletal muscle - Start shivering producing heat
- Body hair - hair erector muscles contract raising the hairs on skin, trapping a layer of warm air, insulating the skin
- Sweat glands – Sweating stops
- Skin arterioles – Vasoconstriction, blood is diverted away from the skin’s surface reducing heat loss by radiation.
- Metabolic rate – increased to generate more heat
List the ways in which effectors respond to hot temperatures?
- Skeletal muscle - Shivering stops reducing body heat production.
- Body hair - Erector muscles relax causing body hair to lie flat on the skin. This reduces the insulating effect of trapped air.
- Sweat glands – Sweat is released on the skin’s surface. Body heat used to evaporate water in sweat, cooling the skin.
- Skin arterioles – Vasodilation, blood is diverted towards the surface, increasing heat loss by radiation.
- Metabolic rate – Decreases to reduce heat production.
