PHGY 214 Lecture 1: PHGY214 W1L1 notes
14 Feb 2017
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Icf is where life is occurring, so you need the ecf to be functional. Physiology is the chemistry and physics of life. Ecf surrounds everything, so you have to go through it to access the icf. Chemistry of life: cells need specific and static environment. Set point desired value of controlled variable (ie. temperature is 37) Sensor detects the change in the controlled variable (ie. peripheral thermal receptors for temp, chemoreceptors for blood ph) If not, need to do something about it) Effector makes the change necessary, opposes the change detected by sensor. Principally by neural output to make muscles do something, sometimes overt or conscious, but mostly unconscious events done by autonomic nervous system. Positive feedback: increases the stimulus, but there is always a shutoff mechanism. (cid:271)a(cid:271)(cid:455)"s head hits (cid:272)er(cid:448)i(cid:454), se(cid:374)ds sig(cid:374)als for (cid:272)o(cid:374)tra(cid:272)tio(cid:374)s a(cid:374)d o(cid:454)(cid:455)to(cid:272)i(cid:374), (cid:373)ore a(cid:374)d (cid:373)ore contractions until baby is birthed. Feedback loops are accurate but not always absolute.
