PSL300H1 Chapter Notes - Chapter 1: Feedback, Fluid Compartments, Extracellular Fluid
Document Summary
Ho(cid:373)eostasis is the stability of the body"s i(cid:374)te(cid:396)(cid:374)al e(cid:374)vi(cid:396)o(cid:374)(cid:373)e(cid:374)t. (we usually look at extracellular fluid since its easier to analyze than intracellular fluid and cellular homeostasis ) Equilibrium implies that composition of body compartments is identical. Ecf a(cid:374)d icf a(cid:396)e i(cid:374) a state of dise(cid:395)uilib(cid:396)iu(cid:373). This is the (cid:862)steady(cid:863) (cid:894)but (cid:374)ot e(cid:395)ual(cid:895) state. Regulated variables are kept in their acceptable range by physiological control mechanisms that kick in if it goes too far from the optimum set point. Input signal: controller (or integrating centre) that integrates info and initiates response, output signal (that creates a response) Local control is restricted to tissue- a response is sensed by nearby cells in the tissues which in turn release a chemical response signal. Long distance reflex control is similar but more complicated. Usually for changes that are widespread through the body (systematic). A physiological reflex has 2 parts: a response loop and feedback loop.
