Page 85 - Alaska A & P Primer

SECTION 14
THE SOMATIC NERVOUS SYSTEM
STUDY QUESTIONS
1. What type of receptor cell is responsible for transducing pain stimuli?What level of the brain stem is the major input to the cerebellum?
2. Following a motorcycle accident, the victim loses the ability to move the right leg but has normal control over the left one, suggesting a hemisection some- where in the thoracic region of the spinal cord. What sensory deficits would be expected in terms of touch versus pain?
3. What type of receptor cell is involved in the sensations of sound and balance?
4. Which region of the frontal lobe is responsible for initiating movement by di- rectly connecting to cranial and spinal motor neurons?
When high temperature is sensed in the skin, a reflexive withdrawal is initiated by the muscles of the arm. 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.
SECTION OBJECTIVES
1. Describe the components of the somatic nervous system
2. Name the modalities and submodalities of the sensory systems
3. Distinguish between general and special senses
4. Describe regions of the central nervous system that contribute to somatic functions
5. Explain the stimulus-response motor pathway
MOVIE 1.25 Somatosens- roy Tracts 7:06 minutes Khan Acad- emy
Watch
https://youtu.be/vrmKqH8d1RM
MOVIE 1.26 Sensory System 10:31 minutes Bozeman science
Watch https://youtu.be/TAzTFgPSPiU
The somatic nervous system is traditionally considered a division within the peripheral nervous system. However, this misses an important point: somatic refers to a functional division, whereas peripheral refers to an anatomic division. The somatic nervous system is responsible for our conscious perception of the environment and for our voluntary re- sponses to that perception by means of skeletal muscles. Peripheral sensory neurons re- ceive input from environmental stimuli, but the neurons that produce motor responses originate in the central nervous system. The distinction between the structures (i.e., anat- omy) 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. When you touch a hot stove, you pull your hand away. Sensory receptors in the skin sense extreme temperature and the early signs of tissue damage. This triggers an ac- tion potential, which travels along the sensory fiber from the skin, through the dorsal spi- nal root to the spinal cord, and directly activates a ventral horn motor neuron.
This content is available for free at https://cnx.org/content/col11496/1.7
State of Alaska EMS Education Primer - 2016
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