Wednesday 1 14 15 Homeostatic Control System HCS Biorhythms Figure 1 10 Biorhythms o Body temp drops at night o Plasma growth hormone spikes at night o Ex circadian daily sleep o annual yearly fat deposition for insulation in the winter o lunar month we are more active when there is a full moon relative to when there is no moon out We can anticipate the next full moon since the cycle is regular so we become more active Our bodies have a proactive response instead of reactive so we have feedforward activity o We have internal trigger components that tell us what time of day it is and o This clock is not determined by the environment whether we are active or inactive internal clock If you were locked in a windowless room you would still be going to bed at night and being active during the day We can make minor adjustments to our internal clock though Set up for survival adaptation genetic o An adaptation is a genetic change a mutation We don t adapt to waking up at a different time because our genes have not changed Instead we acclimate o We can survive better because we save energy by being proactive instead of reactive Adjustable within limits acclimatization o We can adjust when we go to different time zones It is not instantaneous though jet lag o Clock reset changing our set point environmental Ex changing our wake up time and acclimating to waking up at 8am cold This reset happens as a result of the environment o Use based not a genetic change it is an individual change During the winter 55 F feels warm but during the summer it feels o This is a change that happens to the individual not the species adaptation is a change that happens at the species level o Usually reversible Exception developmental acclimatization Wednesday 1 14 15 Ex if a pregnant woman drink alcohol she changes the physiology of the fetus HCS Reflex Arc Figure 1 7 o Stimulus receptor integrating center effector response negative feedback loops back to stimulus to form a cycle Receptor o Receives a stimulus o External or internal Afferent Pathway receptor integrating center Integrating Center o Lets us know if we are in steady state or not o Compares to our Set Point If same ish done If off negative feedback We have to use our efferent pathway to do negative feedback in attempt to return to our Set Point Efferent Pathway integrating center effector Effector o Get response physiological change How Control for HCS via Signals how cells communicate to each other to induce physiological change Chemical messenger o Most travel through extracellular EC fluid o Messenger Released by Pathway Endocrine aka hormone Gland or neuron Paracrine Most cells neurotransmitters Neurons Communicates with Distant effectors Neighbor effectors Next neighbor neuron or effector Plasma the water portion of your blood Interstitial fluid IF IF of the synapse Q of the week How can we collapse these 3 messengers into only 2 groups Think about what they have in common
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