EHS 385 Lecture Notes - Lecture 9: Autonomic Nervous System, Cardiac Muscle, Basal Ganglia

• School: UMass Boston
• Department: Exercise and Health Science
• Course: EHS 385
• Professor: Rachel Drew

Document Summary

Sensitive to changes in chemical environment surrounding muscle (h+ ions, co2, k+) Provide central nervous system (cns) w/info about metabolic rate of muscular activity: important in regulation of cardiovascular and pulmonary responses to exercise. Somatic motor neurons of peripheral nervous system (pns: responsible for carrying neural messages from spinal cord to skeletal msucles. Motor unit: motor neuron and all muscle fibers it innervates. Innervation ratio: number of muscle fibers per motor, low ratio in muscles that require fine motor control (23/1 in extraocular muscles, higher ratio in other muscles (1000/1 or greater in larger muscles) Motor unit recruitment: recruitment of more muscles fibers through motor unit activation. Size principle: smallest motor units recruited first, produce larger excitatory postsynaptic potential (epsp) and result in action potential sooner. Types of motor units: type s (slow) for type 1, type fr (fast, fatigue resistant) or type 2a, type ff (fast, fatiguable) or type 2x.