PSYC 110 Lecture 13: Motor Control
1 Dec 2016
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Types of muscles: smooth muscles: control the digestive system and other organs, skeletal muscles/striated muscles: control movement of the body in relation to the environment, cardiac muscles: heart muscles that have properties of skeletal and smooth muscles. Muscles: muscles are composed of many individual bers. Each muscle ber receives information from only one axon. One axon may innervate many muscle bers: a neuromuscular junction is a synapse between a motor neuron axon and a muscle. Ber: release of chemicals causes the muscle to contract. Absence of ach causes muscles to relax: movement requires the alternating contraction of opposing sets of muscles called antagonistic muscles. Extensor muscle: extends an appendage or straightens it: muscles that act together are called synergists, two main types of skeletal muscles: Fast-twitch: bers produce fast contractions but fatigue rapidly. Slow-twitch: bers produce less vigorous contraction without fatigue: people have varying percentages of fast-twitch and slow-twitch muscles.
