Homeostasis

what is homeostasis

Regulation of the body's internal environment

interaction between the extracellular and intracellular fluid

depends on mass balance

what is mass balance in the body

law of mass balance: what goes in, must come out

open system that requires input equal to output

what does local refer to in control systems?

Restricted to a tissue

what does reflex refer to in control systems?

A long-distance pathway that uses nervous and/or endocrine systems

what is the sequence of a control system?

Input signal → integration center → output signal → response

what is homeostasis disruption?

when the body is in a dynamic steady state (no equilibrium)

what is compensation and what happens when it fails?

a) when homeostasis is established

b) failure leads to disease

what is pathophysiology?

study of the failure to compensate

what is the sequence of a response loop?

stimulus → sensor → input signal → integration center → output signal → response

what is a (+) feedback loop?

response reinforces the stimulus and sends the variable farther from the setpoint

requires an outside factor to shut off the feedback cycle

what is a (-) feedback loop?

response counteracts the stimulus, shutting off the response loop

stabilizes the variable

what is feedforward control?

control that takes place before a work activity is done

anticipates change

what is hydrostatic pressure and why is it a physiological problem

a) pressure exerted by a fluid at equilibrium at a given point within the fluid due to the force of gravity

b) the heart must pump blood up against fluid in the upper body

what is the arterial baroreceptor reflex?

(-) feedback loop

what are G-forces?

force of gravity on a particular extraterrestrial body

under high G-upward acceleration, hydrostatic forces increase the pressure of the fluid at the bottom of the tubes