Exam One - 1.1 Intro to Physiology Flashcards
teleological approach
evolutionary/adaptive significance - the WHY
mechanistic approach
physiological process - the HOW
List the 4 themes of physiology
structure and function are closely related
living organisms need energy
information flow coordinated body functions
homeostasis maintains internal stability
Homeostasis
the tendency toward a relatively stable equilibrium between interdependent elements especially as maintained by physiological processes
law of mass balance
mass balance = existing body load + intake/metabolic production - excretion/metabolic removal
does homeostasis = equilibrium?
No
- steady state disequilibrium
- simple diffusion to equilibrium
- membrane potential = stead-state
Hormesis
a theoretical phenomenon of dose-response relationships in which something that produces harmful biological effects at moderate to high doses may produce beneficial effects at low doses
example - wine
What do control systems do?
Keep regulated variables near setpoint
What are the two types of control systems?
local and reflex
most local: molecular
then cellular
then tissue
most reflex: systemic
What are the components of control systems in order?
input signal
integrating center
output signal
response
Are negative or positive feedback loops homeostatic?
Negative
What is the most common example of a positive feedback loop?
Childbirth - increased stretch increases oxytocin release until an outside stimulus (birth) stops the lease of oxytocin
Control system steps for reflex
stimulus
sensor
input signal
integrating center
output signal
target
response
explain setpoint oscillations
go back and forth turning negative response loop on/off to keep variable between acceptable range
