CNS PNS ANS Q2 Flashcards
What are the 3 main parts of the spinal nerves and where do the central and ventral roots merge?
Roots, Trunk, and Rami. The roots merge in the trunk.
List and describe the meninges of the spinal cord.
Dura mater: this is the most outer region is very tough due to its fibrous network. Deep to it is the Arachnoid mater which is highly vascularized and will look like a spider web network. Deep to arachnoid is the Pia mater. It is the most delicate and will be intimate to the spinal cord.
Where do the sympathetic nerves originate from?
Where do the parasympathetic cell bodies reside?
T1-L1 spinal nerves from the paravertebral ganglia.
In the brainstem and S2-S4 spinal nerves.
What makes up the PNS? (describe the parts)
Autonomic nervous system which deals with the involuntary control and Somatic nervous system which deals with the voluntary control.
Explain the difference between dermatome and myotome
Dermatomes are regions of the skin that correspond to a given spinal cord level. Myotomes are the muscles that correspond to a given spinal cord level.
Where does the caudal extent of the spinal cord end?
L1 L2 area.
The gray matter is made of 3 horns. What are they and which cell bodies are contained in each?
Ventral: Somatic
Lateral: Visceral. Exit out the ventral roots
Dorsal: Somatic and visceral. Referred to as secondary cell bodies. Exit out the dorsal roots.
Where do the spinal nerves emerge from?
There is exception to this, what is it?
They emerge directly below their corresponding vertebra. The exception to this is with the cervical region, they emerge above. IE C1 spinal nerve would be above C1 vertebra while T1 spinal nerve emerges above T1 vertebra. Remember that there are 8 cervical spinal nerves even though there are only 7 vertebrae.
There are 4 places where post ganglionic neurons are located, where are they?
Dorsal root ganglion, Paravertebral ganglia, Preaortic ganglia, and intramural ganglia.
What are the two parts of the autonomic nervous system?
Sympathetic (fight or flight and Parasympathetic (rest and digest)
What do the paravertebral ganglia serve?
Sympathetic neurons
Where is the subarachnoid space and what is it filled with?
What are the dentate ligaments?
It is the open area where the arachnoid mater is found. It is filled with CSF.
They anchor the spinal cords to the walls of dura mater
Review the dermatomes for the following spinal cord levels. C2, C4, C5, C6, C7, C8, T1, T4, T7, T10, L1.
C2- Occipital protuberance C4- Collar C5- Lateral shoulder C6-Thumb C7-Middle finger C8-Little finger T1-Medial elbow T4-Nipple T7-Xiphoid T10-Umbilicus L1-Inguinal
Explain the functions of the white and grey ramus communicans
The white rami are preganglionic sympathetics between the spinal cord and the chain. The grey rami are pre and post ganglionic sympathetics traveling to the periphery. Note that in the T1-L2 you will see both grey and white, while above or below you will only see grey.
What is the function of the splenic nerve?
The preganglionic sympathetics traveling from the sympathetic chain to the preaortic ganglia.
The sympathetic nervous system will control the smooth muscles of which blood vessels and for what reason?
The parasympathetic nervous system will control the blood vessels of which organs and glands?
Sympathetic- Blood vessels to the organs to decrease blood flow for other parts of the body.
Parasympathetic- Visceral organs IE to cause the muscle contractions of digestion.
What is the primary function of the ventral, lateral, and dorsal horns of the spinal grey matter?
Ventral is motor, Lateral is sympathetic nervous, and dorsal is sensory.
How many vertebrae are there in the cervical, thoracic and lumbar regions?
Cervical-7 Thoracic-12 Lumbar-5
As the body continues to develop from a fetus, what happens to the nerves located in the lumbar region?
Because the nerves do not grow as fast as the vertebral column, the nerves are drawn caudally.
Which matter sends information to the brain and which sends the information away?
White matter sends information to the brain and grey is away.
What is the dorsal root ganglion?
Location of the cell bodies in the dorsal root.
What do the preaortic ganglia serve?
Visceral sympathetic neurons.
Which matter contains the myelination, white or grey?
White matter
Why does the spinal cord increase in size as you ascend towards the brain?
As you move closer to the brain you will have more nerves converging.
What do the neural crest cells form from the embryo?
Peripheral nerve ganglia
What are the myotomes for the spinal nerves C5, C6, and C7?
C5- Shoulder abduction
C6- Elbow flexion, wrist extension
C7-Elbow extension
What is the afferent and efferent pathways?
Afferent is carrying signals from the periphery to the central nervous system and efferent is carrying signals from the CNS to the periphery.
Which roots contain the afferent pathway and which contain the efferent pathway?
Dorsal
Afferent
Ventral
Eefferent
What do the parasympathetic ganglia serve?
Parasympathetic neurons.
What is an explanation as to why there is not as much grey mater located in the thoracic vertebrae?
There is not a whole lot of motor action being performed in the trunk.
What makes up the CNS?
Spinal cord and brain
In regards to the spinal cord, what is the gray matter and white matter composed of?
Gray matter is the cell bodies, or where the nucleus of the nerve is located.
White matter consists of the axons sending the information back to the brain.
What do the dorsal root ganglia serve?
Sensory for somatic and visceral
