Spinal Cord
What is the Spinal Cord?The spinal cord is a slender column that passes downward from the brain into the vertebral canal. It continuous with the brain and begins where nervous tissue leaves the cranial cavity at the level of the foramen magnum. The cord tapers to a point and terminates near the intervertebral disc that separates the first and second lumbar vertebrae.Like the brain, the spinal cord is covered by three layers of tissue (meninges).
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Function
Like the brain, the spinal cord is covered by three layers of tissue (meninges). The spinal cord and meninges are contained in the spinal canal, which runs through the center of the spine. In most adults, the spine is composed of 26 individual back bones (vertebrae). Just as the skull protects the brain, vertebrae protect the spinal cord. The vertebrae are separated by disks made of cartilage, which act as cushions, reducing the forces generated by movements such as walking and jumping.
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In short, the spinal cord has 2 main functions:
- It connects a large part of the peripheral nervous system to the brain.
- The spinal cord also acts as a minor coordinating center responsible for some simple reflexes like the withdrawal reflex which is a stimulus tries to avoid damage to the body. (e.i. when touching something hot, you quickly pull your hand away)
Nerves and Roots of the Spinal Cord
Spinal nerves: Emerging from the spinal cord between the vertebrae are 31 pairs of spinal nerves. Each nerve emerges in two short branches (roots):
Sensory roots: carry information to the brain from other parts of the body.
Cauda equina: The spinal cord ends about three fourths of the way down the spine, but a bundle of nerves extends beyond the cord. It carries nerve impulses to and from the legs. It is called that because it resembles a horse tail.
- One at the front (motor or anterior root) of the spinal cord
- One at the back (sensory or posterior root) of the spinal cord
Sensory roots: carry information to the brain from other parts of the body.
Cauda equina: The spinal cord ends about three fourths of the way down the spine, but a bundle of nerves extends beyond the cord. It carries nerve impulses to and from the legs. It is called that because it resembles a horse tail.
Similar the brain, the spinal cord consists of gray and white matter.
- Butterfly-shaped center of the cord- gray matter, which contains cell bodies of interneurons and motor neurons
- Front “wings- motor nerve cells, which transmit information from the brain or spinal cord to muscles, stimulating movement.
- Back horns- sensory nerve cells, which transmit sensory information from other parts of the body through the spinal cord to the brain.
- White matter- columns of nerve fibers that carry sensory information to the brain from the rest of the body and columns that carry impulses from the brain to the muscles.
For additional practice and information about the spinal cord, visit these sites:
http://www.purposegames.com/game/gross-anatomy-of-the-spinal-cord-quiz (Quiz/game about the basic information of the spinal cord)
https://highered.mheducation.com/sites/0072351136/student_view0/chapter12/labeling_exercises.html# (A list of labeling diagrams and games for the spinal cord)
http://www.purposegames.com/game/gross-anatomy-of-the-spinal-cord-quiz (Quiz/game about the basic information of the spinal cord)
https://highered.mheducation.com/sites/0072351136/student_view0/chapter12/labeling_exercises.html# (A list of labeling diagrams and games for the spinal cord)
By Katrina Castillano