TOPIC 8 Thermoregulation Flashcards
What is homeostasis?
It is the balance between external and internal environments which can be regulated through homeostatic control
what feedback mechanism opposes the change?
negative feedback mechanism
what is a positive feedback mechanism
a mechanism that amplifies the change and does not stop until the stimulus is removed
what are the 3 components of feedback mechanisms?
sensor, integrator, and effector
what is an effector?
it is a physiological change triggered by the integrator in response to the stimuli (either decreasing or increasing the physiological variable)
what is a sensor?
a sensor is an organ that detects environmental changes
what is an integrator
an integrator is what decides whether a physiological change must be made by comparing the environmental change with the set point;
it activates the effector
what is body heat generated by?
metabolism
what is controlled in order to regulate body heat
the rate of heat exchange between internal and external (conductance)
what is a homeotherm
a homeotherm maintains constant body temperature; Tb is independent from Ta
what is a heterotherm
an organism with fluctuating internal temperature that is reliant on the evironment
what is an endotherm
an endotherm is an organism that thermoregulates and uses body heat to conserve energy
what is an ectotherm
an ectotherm is an organism that does not thermoregulate and is reliant on Ta
do either ectotherms or endotherms produce body heat?
both produce body heat but ectotherms do not use that heat
when can an ectotherm be a homeotherm?
when the organism is in an environment with constant temperature
what happens to enzymes that aid metabolism at high temperatures?
they become denatured
what happens to enzymes that catalyze metabolism at low temperatures?
they are inactive
what is the range of temperature where thermoregulation does not occur?
thermal neutral zone
what do you call an environmental change that triggers a response?
a stimulus
where can integrators be found in most animals?
in the central nervous system or the endocrine system
what is the integrator for temperature control in animals?
hypothalamus
what feedback mechanism does not result in homeostasis
positive feedback mechanism
where can positive feedback mechanisms often be seen
life-threatening conditions or in the reproductive process
what feedback mechanism results in homeostasis?
negative feedback
what feedback pathway is used for thermoregulation
negative feedback
what is the reason some organisms prefer to thermoregulate?
this keeps the temperature at optimal levels for organisms to move quickly, digest food efficiently, etc, helping organisms maintain the optimal level of organismal performance
how do ectotherms regulate body temperature?
by controlling their conductance
what is an advantage of endotherms over ectotherms?
endotherms can be more active in a broader range of temperature than ectotherms
what is an advantage of ectotherms over endotherms?
they don’t need a constant supply of energy to maintain their body temperature
which would eat more, an endotherm or an ectotherm assuming they are the same size and why?
an endotherm because they need more energy to thermoregulate
what happens to the metabolic rate of endotherms at low temperatures?
it increases to generate extra body heat
