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 nerve fibers that go toward the CNS?
What are the nerve fibers that go away from the CNS?
What type of fiber is found in a ventral root of a spinal nerve?
Pure efferent fibers (away)
What type of fiber is found in a dorsal root of a spinal nerve?
Pure afferent fibers (toward CNS)
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).
Where is the spinal cord enlarged?
C3 - T2 for upper limbs, and T9-12 for lower limbs.
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 conus medularis?
Narrowing at the end of the spinal cord L1 - L2.
What is the cauda equina?
Dorsal and ventral roots of spinal nerves caudal to the end of the spinal cord.
What are the coverings of a nerve?
Endoneurium, perineurium, epineurium.
Where are the cell bodies of nerves in the CNS? PNS?
CNS = nuclues. PNS = ganglion.
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.
Where does a spinal nerve join and exit from the spinal column?
What is the intervertebral foramen?
Where a spinal nerve joins and exits from the spinal column.
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 arachnoid mater? Type of material?
Middle covering of spinal cord. Filamentous.
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 dorsal rami of spinal nerves?
Back skin and deep muscles of the back.
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.
What is a group of nerves called?
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.
What are the axons of nerves in the CNS called?
What are the cxell bodies of nerves in the spinal cord called?
What kind of nerve fibers are bipolar?
What kind of nerve fibers are unipolar?
What are the first splits of a spinal nerve called?
Ventral and dorsal ramus.
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.
Where in the spinal cord is anesthesia given?
The epidural space (outside the dura mater)
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 C7 and T1?
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 vertebrae border cranial nerve 4?
C3 and C4.
What vertebrae border thoracic nerve T7?
T7 and T8.
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.