Lecture 1 Flashcards
physiology
study of normal functioning of living organism including all its chemical and physical processes
physiology is an….. science
integrative
emergent properties
properties of a system that can’t be explained by knowledge of individual components but the complex, nonlinear interactions
physiology is closely tied to…
anatomy
levels of organization
molecules, cells, tissue, organ, organ system
functional
“why” - considered a teleological approach
mechanism
“how” - considered a mechanistic approach
Physiology often focuses on which approach?
mechanistic
homestasis
ability to maintain a stable internal environment
What are key principles in physiology?
homeostasis and regulation of the internal environment
Who coined the term homeostasis?
Walter Cannon, 1929
What is considered the internal environment?
Extracellular Fluid (ECF)
extra cellular fluid
surrounds cells and is a buffer between cells and external environment
dynamic steady state
materials constantly moving back and forth; stable disequilibrium
homeostasis depends on…
mass balance
law of mass balance
amount of a substance in body is to remain constant - any gain must be offset by an equal loss
Maintaining ECF will result in maintenance on…
ICF
Regulated variables kept within a normal range by…
control mechanisms
local control systems
restricted to tissues or cells involved
reflex control systems
changes widespread throughout body and refers to any long distance pathway that uses the nervous, and/or endocrine system
reflex control is broken down into what two parts?
response loop and feedback loop
response loop
stimulus, sensor, input signal, integrating centre, output signal, target, response
feedback loop
modulates response loop
-influence the input
anatgonistic
mechanisms that increase when too low and decrease when too high
negative feedback loops
response opposes or removes signal; stabilizes; homeostatic; insulin secreted when blood glucose is high
positive feedback loops
response reinforces stimulus, sending variable farther from set point; require intervention; not homeostatic; labor
feedforward control
allow body to predict a change is about to occur; hungry (see food)
biorhythms
variables that change predictably and create repeating patterns of cycles of changes
biorhythms
variables that change predictably and create repeating patterns of cycles of changes
