Homeostasis 1 Flashcards
Cells are ____ and ____ organised into tissue and organ systems.
Structurally, functionally.
Define tissue.
Groups of cells that share the same characterisations (e.g muscles).
Define organs.
Collections of tissues, usually of several different types, that synchronise to perform a particular function.
What is the equation of life?
Nutrients + Oxygen —> ATP + CO2 + Wastes
What is homeostasis?
When one thing increases, another must increase/decrease to meet the demand and prevent disturbance in the system.
Define physiology.
The study of how the body should work and what happens when things go wrong.
Define negative feedback.
When an original trigger starts a response and the aim is to turn off the original trigger. Important for homeostasis.
Name 3 challenges to our internal environment.
External temperature, diet, exercise.
How can temperature be controlled?
Vasodilation/Vasoconstriction, sweating.
At extremes, homeostasis becomes more/less effective.
Less
Where are integrating systems often found?
The brain.
Describe the process of negative feedback?
Change in controlled variable -> Stimulus -> Receptor -> Integrating Centre -> Effector -> Response
Define a feed forward system.
More sophisticated than negative feedback as it can predict and prevent changes.
Define positive feedback.
When an initial disturbance sets off events that lead to an even greater disturbance. Common in pathophysiology.
Define a nerve action potential.
Depolarisation creates an instability in the membrane, increases sodium permeability, allows more sodium cells to go into the cell. Makes membrane more unstable, increases depolarisation and continues.
