Neuromuscular Physiology: Muscle Contraction, Reflexes, and the Role of the Cerebellum - P, Study notes of Biology

Download Neuromuscular Physiology: Muscle Contraction, Reflexes, and the Role of the Cerebellum - P and more Study notes Biology in PDF only on Docsity! 17 February Figure 10.4 Extrafusal muscle Skeletal Intrafusal muscle Embedded in extrafusal muscle A.k.a. spindle fibers Stretch receptors around them Figure 10.5 Passive stretch Hold weight passively Muscle stretches Nerve terminals contain stretch receptors Stretch increases firing frequency Tells how much muscles are being stretched Contract Lift weight Muscle contracts Intrafusal muscle slackens – action potential goes down, slackens Lower muscle neurons (within spine) Contraction based on alpha motor neurons Gamma motor neurons to spindle fibers Fire → increase tension on spindle fiber No longer slack Figure 10.6 Knee jerk reflex Tendon hit, stretched Muscle pulled forward (passive stretch) Stretch receptors activated Signal enters spinal cord Alpha motor neurons to extensor muscle activated Contraction Interneuron activated → inhibits alpha motor neuron to flexor Shows Stretch receptors are activated Alpha motor neurons to extensor and flexor functional Inhibitory interneuron functional Neuromuscular junctions functional Muscles functional Figure 10.7 Golgi tendon organ embedded in tendon Passive stretch – low rate of firing from Golgi tendon organ Contraction – pulls on tendon, faster action potentials (greater firing frequency) Figure 10.8