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19 Cards in this Set
- Front
- Back
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What are the spinal nerves?
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-8 pairs of CERVICAL NERVES
-12 pairs of THORACIC NERVES -5 pairs of LUMBAR NERVES - 5 pairs of SACRAL NERVES -1 pair of COCCYGEAL NERVES Total of 31 pars of nerves. |
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What is the location of the Spinal Cord?
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Located within the vertebral canal of the vertebral column Cord extends from the medulla to the
superior border of the second lumbar vertebrae and terminates at the conus medullaris |
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What are the 5 parts of the spinal cord?
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1. Gray Matter - shaped like a butterfly and arranged into horns (anterior, lateral and posterior)
2. White matter is around the outside of the butterfly and arranged into columns (anterior, lateral and posterior) 3. Posterior median sulcus (Dorsal sulcus) 4. Anterior median fissure (Ventral fissure) 5. Central canal - surrounded by the Gray commissure |
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What are the spinal roots?
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Roots unite to form a spinal nerve which then emerges from the intervertebral foramen.
1. Dorsal root - carries sensory (afferent) impulses - dorsal root ganglion is a bulge on the dorsal root which contains cell bodies of sensory neurons. 2. Ventral root - carries motor (efferent) impulses |
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Each nerve is wrapped in special connective tissue, what is found inside the nerve?
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- endoneurium - encloses each axon
- perineurium - around a nerve fascicle (bundle) - epineurium - surrounds all fascicles |
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What are the two main functions of the spinal cord?
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1. Provides a conduction pathway
- each column of white matter in the spinal cord contains bundles of axons (tracts) - tracts have a common origin (or destination) and carry similar - information - tracts are continuous with white matter tracts in the brain 2. Serves as an integration center for spinal reflexes |
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What are two processes that conduction pathways are used for?
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-Sensory input travels along tracts toward the brain (ascending pathways)
-Motor output travels along tracts toward skeletal muscle and other effector tissues (descending pathways) |
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What is cross over?
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Right side of the body interprets sensory information from the left side of the body and visa versa. Also, the right side of the brain controls the muscle activity of the life side and visa versa.
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What is a Dermatome?
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It is the area of the skin that provides sensory input to the CNS via 1 pair of spinal nerves. Nerve supply in adjacent dermatomes overlap somewhat. Can also determine if sensation is lacking which spinal nerve is damaged.
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What is the purpose of the ascending tract of the nervous system?
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Informs nervous system about internal/external changes, and includes the general senses as well as special senses.
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What is a proprioceptor?
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They occur in muscles, tendons and join capsules; sense body position/movement of the joints. The sensation begins at a somatic receptor - either a specialized cell of dendrite of a sensory neuron.
Senses pain, temp., touch, tickle, itch from limbs, trunk, neck, posterior head |
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What are the functions of the first, second and third order neurons in the ascending tract?
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-First order neuron conducts sensory information from the receptor to the spinal cord or brain stem.
-Second order neuron conducts the impulse to the thalamus -Third order neuron conducts to the primary somatosensory area of the cerebral cortex. |
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Describe the Descending tracts of the spinal cord
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Contains axons that convey motor output down the effectors includes upper and lower motor neurons.
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What are upper and lower motor neurons?
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-Upper motor neuron has its cell body in the cerebral cortex (direct pathway) OR in the brain stem (indirect pathway)
-Lower motor neuron has its cell body in the brainstem or spinal cord. Axon of the lower motor neuron innervates the skeletal muscle. |
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Describe the direct/pyramidal tracts and indirect/extrapyramidal tracts.
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-Direct tracts have nerve impulses from the primary motor area. It causes precise, fast, voluntary movement of skeletal muscle.
-Indirect tracts have nerve impulses that come from the brain stem and cause involuntary skeletal muscle movements - balance, posture, and some head movements. |
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What is the Reflex center?
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Reflex is a rapid, involuntary and predictable motor response to a certain stimulus. There is no conscious thought involved. Some reflexes are inborn and others are learned.
Includes Somatic reflex and Autonomic reflexes |
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What are Somatic and Autonomic reflexes?
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-Somatic reflex involves contraction of skeletal muscle.
-Autonomic reflex involves the response of smooth muscle, cardiac muscle and glands. |
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What are the 5 components of reflex arcs?
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a) Sensory receptor
b) Sensory (afferent) neuron c) Integrating center d) Motor (efferent) neuron e) Effector |
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What is a Stretch reflex?
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Stretch reflex is an important somatic reflex
- stretching of a muscle stimulates a sensory receptor (muscle spindle) - muscle spindle monitors changes in the length of the muscle - reflex response is contraction of the skeletal muscle |
