Spinal Nerves

Who’s The Boss? The brain and spine make up the central nervous system They are two primary players in any decision, thought or emotion that you experience in your day However, the workload is not equal Sometimes one of the two is asked to do much more

Who’s The Boss? Much like the government of any country, the brain and spine handle issues that arise But in any country, the president is not tasked with handling the simple day to day matters As an example, the president of the USA is not tasked with finding a lost cat

Who’s The Boss? In this scenario, the brain can be thought of as the president The conscious brain makes many of the big decisions that you have throughout the day An example might be when you decided what to wear to school today

Who’s The Boss? The spine functions more like local government It connects the outside “people” with the inside “government” When sensory information comes in it sends it to the proper place in the brain and when signals go out it directs them to the proper location in the body It also handles some small issues that would take too much of your conscious brain’s time

The Spinal Cord Your spinal cord is structurally and functionally integrated with your brain The spinal cord is a long tube of nervous tissue that extends from the base of the brain all the way to the lumbar region of the spine The way that it built and structured tells us a lot about the way that it works

The Spinal Cord The adult spinal cord measures approximately 18 inches in length and.5 inches in width You might be confused with the length, however the spinal cord does not run the entire length of the spine It ends between L1 and L2 The cauda equina consists of the nerves that function below the spinal cord in the lumbar and sacral regions

The Spinal Cord Just like the spine, the spinal nerves are named based on the location of the nerves Cervical nerves are found in the cervical section of the spine Thoracic nerves are in the thoracic section of the spine Lumbar nerves are found in the lumbar section of the spine

The Spinal Cord The spinal cord also has two thicker regions called enlargements The cervical enlargement is located between C5 and T1 and is a collection of nerves that supply the upper limbs The lumbar enlargement is located between L2 and S3 and is a collection of nerves that supply the lower limbs

The Spinal Cord The actual cross sectional shape of the spinal cord is oval However the dorsal side of the spinal cord has a shallow longitudinal groove called the posterior median sulcus A much larger groove is seen on the ventral surface is called the anterior median fissure

Spinal Nerves Each spinal segment is associated with a pair of dorsal root ganglia These contain the cell bodies of sensory neurons The sensory nerves connect to the spinal cord by the dorsal root

Spinal Nerves A pair of ventral roots bring information back to the motor neurons These nerves function to bring information from the spinal column to the outlying organs This allows you to control your own body

Spinal Nerves The dorsal roots and the ventral roots meet at the spinal nerve Two spinal nerves are associated with each vertebrae and control the sides of the body Each spinal nerve is a mixed nerve A mixed nerve has both motor neurons and sensory neurons

Video h?v=RiGgNarlvK4 h?v=RiGgNarlvK4

Naming the Nerves There is a specific arrangement to the spinal nerves These nerves are named very specifically to designate what part of the body they service In the thoracic, lumbar and sacral regions the associated spinal nerve is named for the vertebrae directly superior to it

Diagram: Sideways…

Naming the Nerves However this pattern changes when referring to the cervical nerves This is because the first pair of spinal nerves pass between the skull and C 1 In order to compensate for this, the cervical nerves are named after the vertebra directly inferior to the nerve

White vs Gray The neurons that are in the spine are one of two types Grey neural tissue is composed of dendrites, axons and synapses White neural tissue is composed of cells with myelinated axons that connect all of the neurons in the brain and spine

White vs Gray In a cross section of the spinal cord shows that the gray matter and the white matter are not uniformly distributed The white matter is located on the outside of the spinal cord The gray matter is located on the inside of the spinal cord

Video h?v=xXWsQrl1N7s h?v=xXWsQrl1N7s

Surrounding the Spine The spine is sectioned off from the other parts of the body The spine is sectioned off the other parts of the body because it helps protect the spine from injury and infection Different layers of membranes and fluid buffer the spine from the outside world

Surrounding the Spine The spinal meninges are a series of specialized membranes surrounding the spinal cord It has three different layers The outer most layer is the dura matter The middle layer is arachnoid mater The innermost layer is the pia mater

Surrounding the Spine Inside the layers of the meninges there is a fluid called the cerebrospinal fluid (CSF) This fluid serves many roles It acts as a shock absorber, a medium for dissolved gases, medium for nutrients, medium for chemical messengers and waste products

Surrounding the Spine A bacterial or viral infection of the spine is called meningitis Meningitis causes a swelling or inflammation of the spine The swelling stops the flow of CSF creating a backup of waste, a lack of nutrients and a loss of functions of the nerves

Video 015/02/10/moorpark-couple- who-lost-daughter-to-bacterial- meningitis-hopes-their-story- will-save-lives/ 015/02/10/moorpark-couple- who-lost-daughter-to-bacterial- meningitis-hopes-their-story- will-save-lives/

Diseases of the Spinal Nerves h?v=jCaysTThD2Y h?v=jCaysTThD2Y Actual photos – kind of gross… h?v=egQs6EvJtTE h?v=egQs6EvJtTE And there is no way I could ignore this guy… h?v=BoBMhOimUPU h?v=BoBMhOimUPU