MODULE 1 Flashcards
Physiology
the study of the normal functioning of a living organism and its component parts, including all its chemical and physical processes
physiology is an integrative science
Emergent Properties:
properties of a complex system that cannot be explained by a knowledge of a systems individual components
-result from a complex, nonlinear interactions of the systems different components
physiology is an integrative science
closely tied to anatomy:
the structure of a cell, tissue or organ must provide a physical base for its function
Levels of organization
Smallest to largest
atoms - molecules - cells - tissues -organs - organ systems - organism - populations of species - ecosystem of different species - biosphere
cells
smallest unit of structure capable of carrying out life process
4 types of major cells
epithelial, connective, neuron and muscle
tissue
collection of cells carrying out related functions
organ
formation of tissues into a structural and functional unit
organ system
integrated groups of organs
physiologists often focus on a __________ approach
mechanistic
homeostasis
The ability to maintain a relatively stable internal environment in spite of exposure to external variability
Homeostasis and regulation of internal environment are key principles in physiology
ex. blood pressure body temp, ion/molecuel concentration, gas partial pressures ect.
Homeostasis and Disease
If for some reason you cannot maintain homeostasis you will likely be in a disease state
Homeostasis and Disease
external changes:
toxic chemicals
physical trauma
forge in invaders (bacteria or viruses)
Homeostasis and Disease
Internal changes:
normal cell growth
autoimmune disorders
genetic disorders
Homeostasis and Disease
what happens with internal and external change
organisms attempt to compensate
if compensation fails = illness or disease
if compensation succeeds = wellness
internal environment of the body
extra cellular fluid: surrounding cells is a buffer between cells and the external environment
dynamic steady state
We want to keep extracellular fluid constant, because it affect the intracellular fluid
they are in a dynamic steady state
homeostasis depends on mass balance
Law of Mass Balance:
the amount of a substance in the body is to remain constant, any gain must be offset by an equal loss
mass balance = existing body load + intake or metabolic production - excretion or metabolic removal
homeostasis does not mean equilibrium
No net movement
The body compartments are in a manic steady state but are not in equilibrium but rather stable disequilibrium
-goal is to maintain the dynamic states of body compartments
Control systems and homeostasis
To maintain homeostasis the body monitors certain key functions/variables
Control systems can be ______ or _______
local or reflex
all control systems have 3 basic components
- input signal (change is sensed creating an input signal)
- integrating centre (takes in the change)
- output signal (creates an output to return to normal)
response
local control
restricted to tissues or cells involved (smaller area of the body)
ex.
active cells - reduced O2 levels
oxygen levels drop in extracellular tissue
active cells send local signal
O2 levels in tissue restored
Reflex control uses long-distance signalling
Changes widespread throughout the body (systemic) use more complex control systems to maintain homeostasis (blood pressure)
Reflex control refers to any long distance pathway that uses the nervous, endocrine system or both
Reflex control: broken into two parts
- Response Loop (nervous and/or endocrine system
- Feedback loop
-modulates the response loop
-feeds back to ultimately influence the input
stimulus, sensor, input signal, integrating center, output signal, target, response
Reflex control can be ______
antagonistic
heater and air conditioner (in the body dual control of heart rate)
negative feedback loops
A pathway in which response opposes or removes the signal (stimulus) is known as negative feedback
-stabilizes a system
-homeostatic
-can restore the initial state but cannot prevent the initial disturbance
Positive feedback loops
-Are not homeostatic
-reinforce a stimulus to drive the system away from a normal value rather than decreasing or removing it
-requires intervention or event outside the loop to cease the response
no used to maintain homeostasis
Feedforward control
Anticipatory reflex
-a few reflex have evolved that allow the body to predict a change is about to occur
ex. salivating when thinking about food, the body has learned this adaptation
biological rhythms and changes in set point
variables are regulated within a normal range around a set point but set points vary form person to person or may vary within an individual over time
-can be due to genetics, or constant exposure to a new condition
biorhythms
variables that change predicability and create repeating patterns or cycles of changes
Example of Biorhytms
circadian rhythm (24hr)
Set point changes throughout the day ex. Temperature - lowest point in the morning 6am rises in the evening
Morning people lowest temp is earlier in the morning temp goes up earlier in the morning
Night people their temp is still dropping
