Homeostasis Flashcards
Tissues
Groups of cells that share the same characteristics or specializations
organs
collections of tissues, usually of several different types, that synchronize to perform a particular function
Nutrients + oxygen =
energy (ATP) + CO2 + Wastes
Homeostasis
Maintaining an optimum internal environment within the body for all cells to function
Common changes to our internal environment
external temperature
diet
exercise
Negative Feedback Control System
- Magnitude of change is a monitored variable (such as body temperature), which feeds that information to an integrating centre.
- integrating centre compares the change to a reference level
- any difference between the actual level and the reference level generates another signal, which is fed to an effector mechanism, in such a way as to produce a response (eg shivering or sweating) which corrects the original change
Integrating centre
includes reference level
eg the hypothalamus
Feed-forward systems
additional receptors permit system to anticipate change and therefore activate response earlier
Positive feedback mechanisms
initial disturbance set off a train of events that lead to an even greater disturbance
eg nerve action potential, ovulation, sexual behavior
more associated with PATHOLOGY
water is ……% body weight
60
Total mls of water gained and lost in 24 hours
2550
water split into 3 compartments
intracellular fluid
interstitial fluid (fluid between cells)
plasma (fluid component of blood)
Extracellular fluid
interstitial fluid AND plasma
material moving between cells and the ECF must cross the
cell membrane
selectively permeable
Total body water is
42 litres
so ECF is 14
