BIOL 1412 Lecture Notes - Acetyl Group, Desmosome, Facilitated Diffusion

• School: University of Manitoba
• Department: Biological Sciences
• Course: BIOL 1412
• Professor: Paul Messing

Document Summary

Result of output - variable moves back toward the set point ie. in opposite (neg. ) direction to the change that triggered the response (input) Eg. body temp. ( = variable) set point 36 to 37. 8 c. Brain hypothalamus thermostat cells (r) detect high temp. (stimulus) dilation) + sweat glands. E=smooth muscle of blood vessels in skin relax (causing secrete sweat. Result = core blood to skin surface and sweat evaporates = heat loss and temp. (opposite direction of input) temp. eg. 2. Set point can change eg. fever = cause by bacterium: positive feedback. Output intensifies the input (enhances it) eg. childbirth - labour. +ve feedback = contractions posterior pituitary gland releases oxytocin (hormone) *con"ts until endpoint ( = baby born) Barrier to h2o soluble substances - not to small mol. s (o2 & co2) & lipid soluble mol. s: membrane proteins a) transport proteins, channels (fig 3. 3) & (fig. Selectively permit channel-mediated simple diffusion of h2o & specific ions.