Chapter 1 - Introduction Flashcards
Teleology
In philosophy, the science or doctrine that attempts to explain the universe in terms of ends or final cause
Mechanistic
That which explains the phenomena of nature on the principles of physical processes (often in sequence of events)
Physiology
“Knowledge of nature” The study of the mechanisms by which living organisms function
Organization of the body
Cell to tissue to organs to systems to whole body
The types of tissues
Neural, muscle, epithelium, and connective
Organ (def)
Two of more types of tissues
System (def)
A collection of organs
Homeostasis
Maintenance of a relatively(!) stable internal environment
Homeostasis maintains
1) concentration of nutrients (glucose, AA, fats)
2) concentration of gases (oxygen, carbon dioxide)
3) concentration of wastes (urea, ammonia)
4) concentration of water and salt—osmolarity
5) pH (blood 7.4)
6) temperature (37° C)
Homeostasis characteristics
1) stability is the balance between inputs and outputs
2) complete constancy is not maintained, only a narrow range of physiological values
3) in a negative feedback system, changes move the variable back toward the initial set points
4) set points can be physiologically reset; raised or lowered
5) not everything can be homeostatically maintained so variables are ranked in a hierarchy
Inability to maintain homeostasis leads to
A pathological condition (departure from nature)
What percentage of the body is water
60
ECF (def)
Extracellular fluid is located outside of and directly around the cells (but still inside the body)
ICF (def)
Intercellular fluid is inside cells
Interstitial fluid
Directly around the cells and is composed of everything the cell needs including nutrients and waste products
ECF is the
Internal environment of the body
ECF includes
Interstitial fluid and blood plasma. Material moving between cells and ECF must cross the cell membrane
Negative feedback loop (def)
Regulatory mechanism in which a change in a controlled variable triggers a response that opposes the change (does not fix, opposes!! the change)
Positive feedback loop (def)
Regulatory mechanism in which a change in a controlled variable triggers a response that continues to drive the variable !!farther!! from the steady state; does not maintain homeostasis
Control pathways strive to maintain
A !!near constant!! setpoint; however normal deviation occurs around the setpoint
In a negative feedback loop, 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. This response tries to maintain characteristics of the ECF.
