lab test 1 ch 4 Flashcards
(32 cards)
Feedback loops
made up of the steps used to achieve homeostasis
homeostasis
is the maintenance of a fairly constant internal environment, even as it faces internal and external stressors.
set point
is the level of each of these variables that the body works to maintain.
internal constancy
is not static, instead it is a dynamic process
cause of diseases and disorders
failure of the body to maintain homeostasis
stimulus(signal)
is a change in a physiological variable from its setpoint
sensor(sensory receptors)
structure that detects that change or stimulus
integrating center
the structure that can analyze the information about the variable, to compare the current state to the desired set point
effector
the structure that can act to adjust the condition by bringing the variable back to its set point
response
the final step of a feedback loop is the outcome of the effector’s action
afferent pathway(sensory neurons) and efferent pathway(autonomic neurons and somatic motor neurons)(info)
are not present in all feedback loops, but they will be in most.
negative feedback loop=
reversal of the original stimulus
positive feedback loop=
amplification in same direction as stimulus
A stimulus must be a variable that can be detected by a sensor.
stove on hand, stimulus is increased temp. felt by receptors in hand
what percent of feedback is muscle and what percent is gland?
- 99% muscle
- 1% gland
the generation of heat is called?
thermogenesis
oral temperature is about ____ than rectal temperature.
0.5 degrees C lower
Body temperature increase following a meal is called:
internal heat production
Heat gain from the sun is this type?
radiant heat gain
Heat transfer from direct contact with an object, say a warm stove is this type:
conductive heat gain
the primary way a resting human loses heat to the environment is by _____ heat loss.
radiant
Setting up a fan to help move warm air off of the skin and replace it with cooler would be an example of this type of heat loss.
evaporative heat loss
These blood vessels/arterioles near the skin surface are involved in maintaining body temperature in the cold and in the heat.
cutaneous blood vessels
this number is an estimate of the number of sweat glands in the skin of the body.
2-3 million