This triggers an action potential, which travels along the sensory fiber from the skin, through the dorsal spinal root to the spinal cord, and directly activates a ventral horn motor neuron.
IN THE SOMATIC NERVOUS SYSTEM SKIN
Sensory receptors in the skin sense extreme temperature and the early signs of tissue damage. When you touch a hot stove, you pull your hand away. The distinction between the structures (i.e., anatomy) of the peripheral and central nervous systems and functions (i.e., physiology) of the somatic and autonomic systems can most easily be demonstrated through a simple reflex action. Peripheral sensory neurons receive input from environmental stimuli, but the neurons that produce motor responses originate in the central nervous system. The somatic nervous system is responsible for our conscious perception of the environment and for our voluntary responses to that perception by means of skeletal muscles. However, this misses an important point: somatic refers to a functional division, whereas peripheral refers to an anatomic division. The somatic nervous system is traditionally considered a division within the peripheral nervous system. Explain the stimulus-response motor pathway.Describe regions of the central nervous system that contribute to somatic functions.Distinguish between general and special senses.Name the modalities and submodalities of the sensory systems.Describe the components of the somatic nervous system.Sensory neurons are activated by a stimulus, which is sent to the central nervous system, and a motor response is sent out to the skeletal muscles that control this movement.Īfter studying this chapter, you will be able to: Figure 14.1 Too Hot to Touch When high temperature is sensed in the skin, a reflexive withdrawal is initiated by the muscles of the arm.
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