Nervous system subdivisionsNervous system divided into PNS and CNSCNS: brain and spinal cordPNS: cranial and spinal nervesAfferent nerves carry sensory info to CNSEfferent nerves carry motor commands away from CNSTypical motor neuronElectrical signal comes in through dendrites and goes out through the axonNeural TransmissionAll living cells polarizedMaintain small difference in electrical potential across cell membraneUnlike other living cells, neuron can alter polarization for brief period of timeions move through cell wall that changes electrical chargeSynapsetermination of axon of one neuron “connected” to dendrite of anotherjunction referred to as synapserelease of a NTMs, triggers continuation of impulse in the dendrite in the next oneAction Potential Generationdepolarization within dendritic zone referred to as Excitatory Post-Synaptic Potential (EPSP)EPSP travels through dendritereaches axon hillock (spike generator)if EPSP exceeds generator threshold, action potential generated that travels along axonNerve Impulse Transmissionmyelinated fibers (M) (fatty insulation)faster transmissiondiameter of transmission depends on diameter: faster with larger diameterUnmyelinated fibers (U)Myelin Sheathmyelinated nerve fibers covered by noncontinuous myelin sheathdiscontinuities called nodes of RanvierMyelinated Fiber Transductioneddy currentdepolarization travels inside cell underneath the fatMotor Systemsbody movements carried out by coordinated contractions of musclesall muscle tissue shares common property of contractibilitythat is, when muscle fiber properly stimulated, it shortensTermsInnervation Ratio: number of muscle fibers innervated by single motor neuronmotor unit:array of one motor neuron and its muscle fibersmotor endplate: junction of final motor neuron and muscle fiberMuscle Action Potential (MAP): action potential spreads along muscle fiberSingle Motor Unitstring cheese examplemuscle fibers like string cheeseMuscle Architecturesarcomere: contractile unit of musclethick filaments: myosinthin filaments: actindifference between thick and thin filaments: more overlapCSD 3112 1st Edition Lecture 4Outline of Last Lecture I. Tissuesa. Connective (continued)b. Nervousc. Musclei. Variationsii. Muscle Actioniii. Leversd. VascularOutline of Current Lecture I. Nervous system subdivisionsII. Motor Neurona. Neural transmissionb. Synapsec. Action Potentiald. Myelin SheathIII. Motor systemsa. Termsb. Muscle architectureCurrent Lecture- Nervous system subdivisionso Nervous system divided into PNS and CNS CNS: brain and spinal cordThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute. PNS: cranial and spinal nerveso Afferent nerves carry sensory info to CNSo Efferent nerves carry motor commands away from CNS- Typical motor neurono Electrical signal comes in through dendrites and goes out through the axon- Neural Transmissiono All living cells polarizedo Maintain small difference in electrical potential across cell membraneo Unlike other living cells, neuron can alter polarization for brief period of time ions move through cell wall that changes electrical charge- Synapseo termination of axon of one neuron “connected” to dendrite of anothero junction referred to as synapseo release of a NTMs, triggers continuation of impulse in the dendrite in the next one- Action Potential Generationo depolarization within dendritic zone referred to as Excitatory Post-Synaptic Potential (EPSP)o EPSP travels through dendriteo reaches axon hillock (spike generator)o if EPSP exceeds generator threshold, action potential generated that travels along axon- Nerve Impulse Transmission o myelinated fibers (M) (fatty insulation) faster transmission diameter of transmission depends on diameter: faster with larger diametero Unmyelinated fibers (U)- Myelin Sheatho myelinated nerve fibers covered by noncontinuous myelin sheatho discontinuities called nodes of Ranvier- Myelinated Fiber Transductiono eddy current depolarization travels inside cell underneath the fat-- Motor Systemso body movements carried out by coordinated contractions of muscleso all muscle tissue shares common property of contractibilityo that is, when muscle fiber properly stimulated, it shortens- Termso Innervation Ratio: number of muscle fibers innervated by single motor neurono motor unit:array of one motor neuron and its muscle fiberso motor endplate: junction of final motor neuron and muscle fibero Muscle Action Potential (MAP): action potential spreads along muscle fiber- Single Motor Unito string cheese example muscle fibers like string cheese - Muscle Architectureo sarcomere: contractile unit of muscle o thick filaments: myosin o thin filaments: actin difference between thick and thin filaments: more