CELL PHYSIOLOGY (Neuron)

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CELL PHYSIOLOGY (Neuron)
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ANATOMY OF A SYNAPSE(Synaptic Knob and Motor End
Plate)
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CELL MEMBRANE
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ACTION POTENTIAL
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CENTRAL NERVOUS SYSTEM

• Sensorimotor cortex
• Basal ganglia
• Cerebellum
• Brain stem
• Spinal cord
• Pyramidal tract
• Extrapyramidal tract

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TYPES OF NEURONS
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SARCOPLASMIC RETICULUM
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EXCITATION-CONTRACTION SEQUENCE 1

• AP moves down neuron
• Release of ACH across synapse, receptor
• Motor end plate P ? muscle action P
• SR releases Ca into filaments
• Inhibits troponin
• ATP split ATPM ? ADPPiM
• A M bonding ADPPiM ? A-MADPPi

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EXCITATION-CONTRACTION SEQUENCE 2

• ATP split completely leaving bridge
• A-MADPPi ? A-M ADP Pi
• Break AM bond with fresh ATP
• A-M ATP ? A MATP
• Myosin advances to next actin, repeat
• Relaxation, Ca released from troponin
• Ca back into SR using ATP

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MOTOR UNIT RECRUITMENT
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MOTOR UNIT CHARACTERISTICS
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TWITCH AND TETANUS
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LENGTH-TENSIONRELATIONSHIP (Active)
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LENGTH-TENSIONRELATIONSHIP (Passive)
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LENGTH-TENSIONRELATIONSHIP (Combined)
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VELOCITY-TENSION RELATIONSHIP

• Concentric
• Eccentric
• Isometric
• ? bonding
• Damping
• Peak power ? vmax

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TYPES OF CONTRACTIONS

• Static (Isometric) constant muscle length
• Dynamic muscle length changes
• Concentric muscle shortens
• Eccentric muscle lengthens
• Isotonic constant external force
• Isokinetic constant velocity
• Isoinertial constant acceleration

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QUICK RELEASE EXPERIMENTS(1 - Defines Active
State)
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QUICK RELEASE EXPERIMENTS(2 Series Elastic
Component)
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HILLS 4-ELEMENT MODEL
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ENDURANCE CURVES

• Voluntary hold
• Static contraction
• Occlusion of blood flow
• Rapid fatigue
• T 1236 - 72.5
• (MVC-15)0.618