Introduction to the Spinal Cord and Spinal Nerves Flashcards
What is the spinal cord?
Provides a vital link between the brain and the rest of the body. Exhibits some functional independence from the brain (reflexes)
What are two important functions of the spinal cord and its attached spinal nerves?
Pathway for sensory and motor impulses
Responsible for reflexes
Where does the spinal cord develop from?
Ectoderm (neuroectoderm/neuroepithelium) as neural plate
What forms after a neural plate? As that formation progresses, what is eventually formed after?
Neural groove and as formation progresses, a neural tube is eventually formed.
What cells become part of the peripheral nervous system?
Neural crest cells
Is dorsal horn sensory or motor?
Sensory
Is ventral horn sensory or motor?
Motor
What do neural crest cells become
Become everything from structures in the head and neck to dorsal root ganglion. Responsible for pigmentation
They migrate down and become structures of the heart (valves)
Where will central processes from the developing dorsal root ganglia grow into?
The spinal cord into the dorsal horn
Where will peripheral processes grow?
Grow into the body and connect with structures so that they can receive somato, sensory and visceral sensory impulses that would travel back to the dorsal horn
What does the ventral horn develop?
Develops the motor cell bodies that will send peripheral processes for motor impulses
Anything happening dorsally has to do with _______
Afferent (effect)
Anything happening ventrally has to do with ________
Efferent (response)
What is cervical enlargement?
Thicker area of the spinal cord that a lot of spinal nerves come out of that form the brachial plexuses and the cervical plexuses
What does the lumbar enlargement provide?
Lumbar and sacral plexuses
How many pairs of spinal nerves are there in the spinal cord?
31
When does the spinal cord end?
Lower thoracic, upper lumbar region and the rest is the cauda equina
What does a long nerve represent?
Lots of cells with single peripheral processes growing out
Are posterior rootlets sensory or motor?
Sensory because posterior is back therefore dorsal and dorsal is sensory
At what age are the 2 enlargements visible on the CNS?
At 3 months old
What is well distinguished by 3 months old?
Spinal cord portion of CNS well distinguished from brain and brainstem regions
How many regions can the spinal cord be divided into?
4 regions that have associated structures and functions Cervical Thoracic Lumbar Sacral
What is the function of cervical plexus?
Innervates things in the neck
What is the function of brachial plexus?
Innervates superficial back muscles, pectoral muscles and upper limb