CH 1: Intro to Human Physiology Flashcards
Oxygen
65%
- element most abundant by MASS w/in human body
Hydrogen
63%
- element most abundant by NUMBER w/in human body
Teology
In philosophy, the science/doctrine that attempts to explain the universe in terms of ends or final courses
Mechanistic
Explains the phenomena of nature on the principles of physical processes
*often seq. of events
Physiology
Study of mechanisms by which living organisms function
“Knowledge of nature”
Organization of the body
cells–>tissues–> organs–>systems–>whole body
Organ
two or more types of tissues
Fluid compartments
ICF & ECF
Intracellular fluid (ICF)
- inside cells
Extracellular fluid (ECF)
- is located outside cells but still inside body
- internal environment of the body
- interstitial fluid
- blood plasma
Material moving b/t cells & ECF must cross what?
The cell membrane
Cells gets their oxygen & nutrients from what?
The ECF
Homeostasis
Maintenance of a relatively stable internal environment
*Body temp increases/decreases, not fixed
Homeostasis maintains?
(Good)
1. Concentration of nutrients
2. Con. of gases
(Bad)
3. Con. of wastes
4. Con. of water & salt
5. pH
6. Temp.
Metabolism (breaking down molecules)
Is an input of heat
Mass balance
input = output
Control pathways strive to maintain near constant set point…
- normal deviation occurs around the set loop
- body sets up mechanism in attempt to stay w/in range
Heat stroke
Water is protected by body (hierarchy), so body temp increases and body “cooks”
- brain cooks
- proteins denature
Stability
Balance b/t inputs & outputs
Complete constancy is not maintained…
Only a narrow range of physiological values
- don’t mind variables changing, but can’t be too far
In negative-feedback system, changes move the variable back toward what?
Initial set point
Set points can be physiologically reset by being what?
Raised or lowered
Why are variables ranked in a hierarchy?
Because not everything can be homeostatically maintained
Inability to maintain homeostasis leads to what?
A pathological condition
- pathophysiology
*Departure from nature
Pathophysiology
Study of disease condition
Homeostasis: 2 types of responses
- Local control
- Feedback (response) loops
Local control
- isolated changes occur w/in a tissue
- stimulus & control occur w/in same area
- a response loop is not utilized
ex: crush finger w/ door
Feedback (response) loops
*2 types: neg. & pos. feedback loop
- long-distance communication & coordination
- stimulus & response are not necessarily together (may not be in same tissue)
- includes nervous/endocrine system
Negative feedback loop
Regulatory mechanism in which a change in a controlled variable triggers a response that tries to oppose the change
- a stimulus is detected by sensors in the body…an effector (organ of response) carries out a response that reverses the trend of the stimulus, so it can try to maintain the characteristics of the ECF
Positive feedback loop
Regulatory mechanism in which a change in a controlled variable will trigger a response that drives us further & further from the setpoint
- creates more stimulus
- doesn’t maintain homeostasis
- body will not generally use it…
Physiological control systems keep regulated variables w/in a what?
A desired range (set-point) during homeostasis
