Muscles and the
Although the peripheral nervous system controls muscle activation, each muscle type is control by a different mechanism. Skeletal muscle is controlled by the somatic nervous system (SNS). It is considered voluntary muscle since it is under our conscious control. Contraction of cardiac muscle is primarily controlled by an internal pacemaker, and the autonomic nervous system (ANS). It is considered an involuntary muscle control, since it is not under our conscious control. Smooth muscle, such as in the digestive system, is also controlled by the autonomic nervous system. Like heart muscle, it is not under our conscious control.
The SNS is responsible for controlling voluntary body movements, such as movement of the arms and legs. It is also responsible for receiving sensory information such as touch, hearing, and sight. The SNS contains neurons that connected with the skeletal muscles, skin, and sense organs. Neurons that control skeletal muscle and organs are called motor neurons. The SNS carries nerve impulses from the brain to the muscle to be moved. Neurons used to receive sensory information are called sensory neurons. A stimulus, such as touch or sound, is converted to an electrical signal by a sensory receptor and transmitted to a sensory neuron. The sensory neuron carries electrical impulses back to the CNS and the brain.
Controlling body movement often involves a complex interaction between sensory neurons, the brain, and motor neurons. For example, what is involved in catching a ball? You see the ball coming towards you. You also see and feel the position of your arms and hands. As your brain sends signals to move the arms and hands, it also receives sensory information feedback. As the ball gets closer, the brain uses visual information about the ball, and sensory information about your body position, to move your arms and hands to the correct position. As the ball hits your hands, your brain signals your hands and fingers to close around the ball. You are not born with this ability. It must be learned through stages of motor development as you grow from bady to child and adult.