october 2nd phys notes

october 2nd phys notes - Physiology 10/02/07 Class notes...

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Physiology 10/02/07 Class notes The nervous system is much faster than the endocrine system because it does not rely on blood. Centra Nervous system versus Peripheral nervous system. Sensory neurons vs motor neurons aka afferent neurons vs. efferent neurons. Parasympathetic controls the smooth muscle Sympathetis controls the skeletal muscle. Synaptic cleft- space between the dedrite and axon in a synapse Nerves use microtubules to quickly transport proteins from nucleus to the axon. Glial cells- support cells for the nervous system. Create barriers between compartments, assist in defense and metabolic assistence. o Found in both PNS and CNS. o In PNS satellite cells and schwann sells (wrap themselves around axon and coats itself with a fatty substance. Secrete neurotrophic factors to help axons grow. o In CNS Oligodecytes- created myelin sheath Astrocytes- help form and support CNS, help Blood brain barrier, Neurotrophic factors, K+ neurotransmtters (moving transmitters to diff nerves to activate different ones) Microglia- kill bactieria Ependymal- barriers between compartments Depolarizing causes electrical signal o Cells rest at -70 mv, K+ creates a -90mv it is the most influencial o The more permeable the ion the more influencial on the resting potential o Graded potentials- Incoming signals that can vary in strength Loose strength over distance and are slower than action potential Travel through the cell body to the trigger zone (axon hillock and initial segment) Subthreshold signals do not generate signal. Suprathereshol sends signal Graded potentials action potential Strong graded many, more than one, action potentials. Each come one after the other with same intensity Graded potentials signals can sum to trip threshold or can cancel out o Inhibitory signal- hyperpolarizes (increase) cause less likely to fire o Graded potentials can be superthreshold as they enter the body, but can be subthreshold by them time the reach the triggerzone o Once an action potential starts it can not be stopped or diminished
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This note was uploaded on 08/21/2008 for the course KINE 301 taught by Professor Gibson during the Spring '08 term at Rice.

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october 2nd phys notes - Physiology 10/02/07 Class notes...

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