Physiology 101 Flashcards
(12 cards)
What are the differences between the extracellular fluid and the intracellular fluid?
The Extracellular fluid has high concentrations of sodium, chloride, bicarbonate ions, cell waste and carbon dioxide. The Intracellular fluid, on the other hand, has high concentrations of potassium, magnesium and phosphate ions.
Homeostasis
The maintenance of almost constant conditions in the internal environment/extracellular fluid.
The motion that makes the extracellular fluid move through the capillaries’s permeable walls.
Kinetic motion that causes diffusion of the fluid through the walls.
Organs responsible for the maintenance of homeostasis of nutrients in the extracellular fluid
Lungs (O2), gastrointestinal tract (carbs) and liver.
Organs responsible for the maintenance of homeostasis of waste removal from the extracellular fluid
Lungs (CO2), kidneys, gastrointestinal tract and liver.
Systems responsible for the maintenance of protection of the body
Immune system and Integumentary system (skin)
Systems responsible for the regulation of body functions
Nervous system and Hormone Systems
Control systems
Not 100% effective (level of effectiveness determined by Gain), genetic or within organs, based usually on negative feedback (like on the O2 and CO2 regulation and the arterial blood pressure regulation).
What is the Gain in the control systems?
Gain = correction/error, for which correction is the difference between concentrations on a regular and defective control system and error is the amount of change in the regular control system that it cannot correct.
Explain how negative feedback works.
One control center executes a certain task, that instead of maintaining homeostasis it causes dysregulation of the body concentration. That dysregulation ignites a negative signal to the control center, giving it feedback to minimize said task, returning to normal.
Negative feedback is the norm in most systems, like the emission of hormones from the hypothalamus for example. It is essentially based on a “less of the same” principle.
Explain how positive feedback works.
One control center executes a certain task, that helps **maintaining homeostasis **after a dysregulation. That effect ignites a positive signal to the control center, giving it feedback to continue with said task.
Positive feedback may cause vicious cycles because it leads to instability by overcompensating or exhorting the control center, like the cascade effect of blood coagulation for example. It is essentially based on a “more of the same” principle.
Explain what feed-forward control is and how it is related to adaptive control.
It is a quick response for immediate impulses that have no time to reach the control center for further instructions. Once the impulse reaches the control center, if it was done wrong, it ignites an adaptive control to correct the immediate impulse the next time it happens, like a delayed negative feedback.
