14.1 Overview of Spinal Cord & Spinal Neves

a. functions of spinal cord

1. provide structural & functional link between brain & body

• relays sensory input & sends to brain

• relays motor output that is initiated from brain & sent to effectors

2. spinal reflexes

• nervous system responses that do not require the brain

  • quickest response to stimulus

a. neuron pathways

2 or more neurons that relay information among CNS, PNS, & body structures

b. spinal cord

cylindrical structure that extends from brain through vertebral column

b. cylindrical part of spinal cord

superior most region

continuous with medulla oblongata

b. throacic part of spinal cord

inferior to cervical part

contains neurons for throacic spinal nervesb

b. lumbar part of spinal cord

shorter segment of spinal cord

contains the neurons for lumbar spinal nerves

b. sacral part of spinal cord

inferior to lumbar part

contains neurons for sacral spinal nerves

b. coccygeal part of spinal cord

most inferior tip of spinal cord

c. 2 roots (posterior & anterior)

anchors to spinal cord

each root is composed of multiple rootlets

c. posterior root

houses sensory neurons

relays sensory input to spinal cord

are unipolar neurons

• extend from dendrites to spinal cord

• located external to spinal cord within posterior root & form posterior root ganglion

c. anterior root

contains motor neurons

relays motor output from spinal cord & controls effectors

are multipolar neurons

• housed in spinal cords

• does not contain a ganglion

c. conus medullaris

spinal cord ending at L1 vertebra

tapering like tip of a cone

c. cauda equina

carries motor & sensory nerves to lower body