10.7 Functions of Afferent & Efferent Nerve Tracts
(Functions of the Spinal Cord OR Spinal Cord Physiology)
- Sensory or Afferent Tracts– Tracts conducting sensory impulses to the brain.
- Motor or Efferent Tracts– Those carrying impulses from the brain to skeletal muscles.
- The spinal cord has two major functions—conducting nerve impulses and serving as a center for spinal reflexes.
Naming The Tracts
- If the tract name begins with “spino” (as in spinocerebellar), the tract is a sensory tract delivering information from the spinal cord to the cerebellum (in this case).
- If the tract name ends with “spinal” (as in vestibulospinal), the tract is a motor tract that delivers information from the vestibular apparatus (in this case) to the spinal cord.
Table 3- Afferent & Efferent Nerve Tracts
(Sensory or Motor)
|Sensory or Afferent Tracts|
|1||Spinothalamic tract||Sensing pain, warmth, coolness, itching, tickling, deep pressure, and crude touch.|
|2||Gracile fasciculus||Discriminative touch, light pressure, vibration, and conscious proprioception (the awareness of the positions and movements of muscles, tendons, and joints).|
|Motor or Efferent Tracts|
|4||Lateral corticospinal||Voluntary movements of skeletal muscles.|
|7||Rubrospinal||Automatic movements and help coordinate body movements with visual stimuli.|
|11||Medial reticulospinal tracts|
Figure 25– Ascending Tracts Figure 26- Descending Tracts
|Explanation is available on
Afferent & Efferent Nerve Tracts