CHAPTER 4 - SPINAL CORD & ASCENDING AND DESCENDING TRACTS

• vertebral column is composed of how many vertebrae

  33
• how many vertebrae in cervical, thoracic, lumbar, sacral, and coccygeal

  7, 12, 5, 5, 4
• segmented and made up of vertebrae, joints, and pads of fibrocartilage called

  intervertebral discs
• (typical vertebra) anteriorly it has? how about posteriorly

  rounded body; vertebral arch
• composed of fibrocartilage, attached to vertebral bodies and the ant. and post. longitudinal ligaments of vertberal column

  anulus fibrosus
• ovoid mass of gelatinous material. Normally under pressure and situated slightly to the posterior margin of the disc

  nucleus pulposus
• if there is a sudden increase in compression load on vertebral column, what will happen to the nucleus pulposus?

  flattened
• with advancing age, the nucleus pulposus become smaller and is replaced by what?

  fibrocartilage
• run as continuous bands down the anterior and posterior surfaces of the vertebral column from the skull to sacrum

  ant. and post longitudinal ligaments
• this ligament is wide and strongly attached to the front and sides of the vertbral bodies and to the intervertebral discs

  ant. ligament
• this ligament is weak and narrow and is attached to the post. border of the discs

  post. ligament
• in cervical region, supraspinous and interspinous ligaments are greatly thickened to form the strong _

  ligamentum nuchae

  
• joints between the articular processes are innervated by branches from the

  post. rami of the spinal nerves
• shape of spinal cord

  cylindrical
• spinal cord begins where

  foramen magnum
• spinal cord starts at the skull, and is continuos at what part of the brain?

  medulla oblongata
• spinal cords occupies two-thirds of the

  vertebral canal
• vertebral column is sourrounded by three meninges:

  dura, arachnoid, and pia mater
• aside from the meninges, further protectin is provided by the

  cerbrospinal fluid
• cerberospinal fluid surrounds the spinal cord in which space?

  subarahcnoid space
• inferiorly, the spinal cord tapers off into the

  conus medullaris
• prolongation of the pia mater

  filum terminale
• the spinal cord is fusiformly enlarged; the enlargements are referred to as the

  cervical and lumbar enlargements
• how many spinal nerves are attached in the spinal cord

  31 pairs
• each posterior nerve root possesses what? Give rise to peripheral and central nerve fibers

  posterior root ganglion
• part of spinal cord seen as H-shaped pillar

  gray matter
• gray matter is united by a thin

  gray commissure
• gray commisure contains the

  small central canal
• a small _ is present in the thoracic and upper lumbar segment pf the cord

  lateral gray column
• what region does not contain fasciculus cuneatus

  lumbar and sacral region
• Most nerve cells are large and multipolar, and their axons pass out in the anterior roots of the spinal nerves

  alpha efferents
• The smaller nerve cells are also multipolar, and the axons of many of these pass out in the anterior roots of the spinal nerves as


  gamma efferents
• nerve cells of the anterior gray column may be divided into three basic groups or columns namely:

  medial, central, lateral
• this ant. gray column group innervates the skeletal muscles of the neck, trunk, and intercostal and abdominal musculature

  medial group
• this ant. gray column group is the smallest and is present in soem cervical and lumbrosacral segments

  central group
• these nerve cells specifically innervate the diaphragm and are collectively referred to as the? which is in what part of the central group?

  phrenic nucleus; cervical part of the cord
• In the upper five or six cervical segments, some of the nerve cells innervate the sternocleidomastoid and trapezius muscles and are referred to as the

  acessory nucleus
• present in the second lumbar down to the first sacral segment of the cord is made up of nerve cells whose axons have an unknown distribution

  lumbosacral nucleus
• present in the cervical and lumbosacral segments of the cord and is responsible for innervating the skeletal muscles of the limbs

  lateral group
• substantia gelatinosa is composed of what type of neurons

  golgi type II