What is meant by the term "spinal nerve"?
A spinal nerve is a nerve that originates from the spinal cord at the union of pure dorsal and ventral roots, as opposed to a nerve branching off more distally in the body.
Where is a nerve formed?
A nerve is formed where it leaves the spinal cord at the union of its dorsal and ventral roots, often associated with passage through the intervertebral foramen.
What are the coverings of the spinal cord called? General name?
Meninges. Pia, arachnoid, and dura mater.
What are the denticulate ligaments? What are they comprised of?
Made of pia mater. Pierces the arachnoid mater and links with the dura mater to suspend the spinal cord.
What type of bone forms the body of a vertebra? The neural arch?
Body = cancellous (spongy) inside, and cortical (compact) outside. Neural arch = cortical (compact).
What are the spinal meninges?
Spinal coverings. Inside to outside: pia mater, arachnoid mater, dua mater.
What is the filum terminale? What is it made of and where located?
It is a continuation of the pia mater past L2 vertebra. It gives longitudinal support to the spine.
What is different about the area at the inferior end of the spinal cord and what is it called?
Conus medularis. Narrowing at the end of the spinal cord, L1- L2.
What are the nerve structures inferior to the end of the spinal cord called?
Cauda equina = ventral and dorsal roots of spinal nerves extending down from the cord to exit the spinal column lower than L2.
What is the cauda equina?
Dorsal and ventral roots of spinal nerves caudal to the end of the spinal cord.
Where in the CNS is the ganglion? What type of nerve fibers?
Dorsal root ganglion. Afferent fibers (sensory fibers.. toward the CNS)
Where do sensory neurons lead?
To the dorsal root ganglion, to the spinal nerve, to the spinal cord.
Where do motor neurons come from?
From the ventral root, from the spinal nerve, from the spinal cord.
What suspends the spinal cord by connecting its coverings together? What are the names of the coverings connected?
Denticulate ligament. Made of pia mater. Pierces the arachnoid mater and links with the dura to suspend the spinal cord.
What is the pia mater? Appearance? What does it become?
Interior covering of spinal cord. Glossy. Becomes filum terminale.
What is the dura mater? Type of material? Where located?
Outer layer covering spinal cord. Fibrous sack. Continues outside spinal canal to cover nerves. Also continues below L2.
What are the spaces between the spinal cord coverings called?
Epidural space (above dura and below canal); Subdural space (between dura and arachnoid); Subarachnoid space (below arachnoid and above pia)
What contains the cerebral spinal fluid?
The subarachnoid space (below arachnoid mater and above pia mater).
Which intermeningeal spaces contain fluid?
Subdural: has thin film of fluid. Subarachnoid = actual space containing CSF.
What is innervated by the ventral rami of spinal nerves?
Extrinsic muscles of the back and everything else.
How many spinal nerves? Each type?
31 total. 8 cervical; 12 thoracic; 5 lumbar; 5 sacral; 1 coocygeal.
Where is the white matter in the spinal cord?
The tracts (CNS name for axons). These are on the outside part of the spinal cord.
Where is the gray matter in the spinal cord?
In the nuclei (cell bodies of neurons in the CNS). These are the sites of syapses, and they are on the inside of the spinal cord.
In a spinal reflex arc, what causes contraction and what causes stretch?
Afferents signal stretch, and efferents signal contraction. An inhibitory interneuron also prevents contraction of the opposing muscle.
What is the name of the cranial nerve that is between C2 and C3 vertebrae?
C III. Cranial nerves are names for the vertebra below (except for C viii which is below C7 and it not named for a vertebra.)
What is the name of the spinal nerve that is between T5 and T6 vertebrae?
T five. All spinal nerves below C8 are named for the vertebra above them.
What are the 2 kinds of ossification?
Endochondral is the ossification of cartilage. And intramembraneous is the ossification of a growth membrane.
What type of joint is found between the vertebra and the intervertebral discs?
These joints are not synovial and thus they fall into the class of joints known as synarthroses. Because they have ligament attachments they are further known as syndesmoses. Because a fibrocartilaginous disk is interposed between the bones of these joints, they are further known as symphyses.