Flashcards in Sievert NS Deck (65):
What do the CNS and PNS consists of?
CNS: Spinal chord and brain
PNS: Cranial nerves and spinal nerves
The PNS subdivides into 2 types? What are the different general and special types of each?
1) General Somatic Afferent (GSA) Touch, pain, pressure, vibration, temp, proprioception
2) Special Somatic Afferent (GSA) hearing, equilibrium, and vision
3) General Visceral Afferent (GVA) stretch, pain, temp, chemical, nausea, hunger
4) Special Visceral Afferent (SVA) taste, smell
1) General Somatic Efferent (GSE): motor innervation of Skel. muscle
2) Special Visceral Efferent (SVE) facial expression, striated muscle fibers
3) General Visceral Efferent (GVE) motor innervation of smooth muscle, cardiac muscle, glands (ANS)
Subdivision of the ANS. What is the other name for the ANS?
Parasympathetic and Sympathetic
AKA General Visceral Efferent
The nervous system of the gut is called...
Isolated from everything else
Length of spinal chord is (bank) to length of Vertebral column
What are the 2 types of PNS nerves?
1) spinal: 31 paires, segmental
2) cranial: 12 pairs
A component refers to whether the fiber is motor or sensory and somatic, visceral or special.
Where do Spinal Nerves go and what components make them up?
1) to body walls
2) GSA, GVA (stretch receptors in blood vessels, GSE (move body parts), GVE (Vasoconstriction/dilation)
Cranial nerves arise from the (blank). Which ones give rise to parasympathetic NS?
1) brainstem and brain
Spinal nervers are made from which parts of the spinal chord? Some travel alone (name example), others mix in a plexus (name example).
Ventral and dorsal
cervical, brachial, lumbar, sacral
Motor fibers originate from cells in the (blank)
The (blank) converge to form a spinal nerve.
a single dorsal or ventral root
Each segment of the cord gives rise to multiple dorsal and ventral rootlets which coalesce to form a dorsal or ventral root.
The (blank) nature of the cord and the rootlets give you an idea that each of the spinal nerves is destined to innervate a particular area of the body.
Dorsal root gang. Contains a cell body that contains (blank) cell body
Even in simple reflexes, what must happen?
a sensory nerve must interact with a motor nerve (monosynaptic)
Ventral roots come from cell bodies in the (blank) horn or the lateral gray, and carry (blank) fibers which are either (bank) or (blank).
2) motor (efferent)
3) somatomotor or visceromotor (autonomics)
Dorsal and Ventral roots come together to form a (blank) which is very short and quickly gives off its component branches dorsal and ventral (Blank).
1) spinal nerve
Dorsal ramus: go to true muscles and skin of the back
- Not necessarily muscles found on the back, but have to actually have to do with back movements
Ventral ramus: goes to everything else
- Distribute to upper limb and lower limb and anterior body wall
supplies motor and sensory to skin and muscles of trunk and limbs
(Blank) enter the dorsal horn and carry sensory fibers (afferents)
sensory cell bodies are located in the dorsal root ganglion (DRG)
True or false: the DRG contains synapses.
Sensory ganglia do not have a synapse
Where are the cell bodies of the autonomics located?
in the lateral horn (intermediate gray) of very specific levels T1-L2 for sympathetics (to SM, sweat glands, hair follicles) and S2-4 for para.
Cell bodies of the (blank) are in the ventral horn.
Cell bodies of somatomotor fibers are in the ventral horn (grey matter) (GSE)
Cell bodies of (blank) fibers are in the DRG.
What kinds of information can make the motor neurons fire?
Sensory fibers or descending input
What kinds of information can make the sensory neurons fire?
Something's not right in Internal organs
True or false: autonomic ganglia do have a synapse.
True, pre and post ganglia
The two processes of the dorsal root are (blank)
Central (off the spinal chord and peripheral near the DRG)
and peripheral (responsible for Intersegmental coordination: walking and swinging arms)
T or F: There are equivalents of DRG for the cranial nerves
Communicating Rami: communicating branch between a spinal nerve and the sympathetic trunk (chain)
Both branches (ventral and dorsal rami) of the spinal nerve have sympathetic fibers on them to contribute to Symp. chain.
(Blank) do not supply the body cavities, only body wall structures.
What nerves supply cavities?
Splanchnic nerves (2 viscera) and the vagus
Rami contain what components?
The sympathetic trunk (T1-L2) travels in a downward direction from the skull, just lateral to the vertebral bodies. It interacts with the spinal nerves or their ventral rami by way of rami communicants. The sympathetic trunk is a fundamental part of the sympathetic division of the autonomic nervous system. It allows nerve fibres to travel to spinal nerves that are superior and inferior to the one in which they originated. Also, a number of nerves, such as most of the splanchnic nerves, arise directly from the trunks.
Follow the path of GVE (ANS) fibers
1) Come off at the ventral root and get on to spinal nerve. All autonomic fibers have to synapse before reaching target.
2) Leave spinal nerve, get into synaptic chain, and synapse
3) Go back to spinal nerve on communicating rami at target
4) Rami go to skin, blood vessels, sweat glands, hair follicles
T or F: there is just one cell in the DRG
False. Hundreds of cells, each cell is destined for a different areas of skin.
What kind of fibers motor or sensory, somatic or visceral need to be on the dorsal ramis vs the posterior cutaneous branch?
Posterior cutaneous branch after it pokes through does not have somatomotor fibers on it; does have GSA, VM
In the anterior and lateral body wall the (blank) ramus travels between the 2 deepest layers of muscle.
AKA intercostal nerves
Continues to branch and give rise to lateral cutaneous branch and anterior cutaneous branch
(Blank) is defined as the area of skin innervated by a single spinal nerve (specifically the cutaneous branch).
What are the 5 dermatomes we need to know?
1) T4 at nipple line
2) T10 Umbellicus
3) C2 back of the head
4) S1 back of leg/foot
5) S3-5 perianal region
What injuries display a segmental (dermatomal) pattern?
Spinal cord injury (herniated dics) Level loss
Nerve root compression
What is a myotome?
Pattern of muscle innervation from single spinal nerve
Muscles get multiple innervation from spine
T or F: In the region of the thoracic and abdominal cavities there is a lot of mixing of the fibers of the spinal nerves.
False. one spinal nerve for the most part goes to a single dermatome.
T or F: In the limbs there is a lot of mixing of spinal nerves in the plexus.
True. In the region of the limbs, however, a single spinal nerve may send some of its fibers into a plexus which undergoes considerable mixing and then messes everything up.
Plexus contains many spinal nerves.
Motor (ventral) and sensory (dorsal) spinal nerves can both enter a (blank) and mix. They then go on to become a variety of (blank) nerves.
Define: C5 innervates lots of muscles that are accessed by different peripheral nerves
Peripheral nerves do not follow a (blank) pattern
symp. (spinal chord) And parasym. (brain stem/sacral chord)
- Whichever one is firing more at a given time, rules effect
Visceral afferents travel on (blank)
ANS always takes (blank) # of nerves
2: 1 CNS (pregang), 1 PNS (post gang)
excepts adrenal medulla
Post gang. fibers in parasymp. synapse (blank) target tissue
The most important job of sympathetics is (blank).
the regulation of blood flow
Sympathetic pre gang. go to (blank) or (blank).
2) front of aorta
Describe how innervation to pelvic viscera travels.
1) Nerves from the lateral horn (ans)
2) exit through the ventral root of the spinal cord (S2-4)
3) continue through the ventral rami.
4) sharply branch to go through the white ramus communicans of paravertebral body (chain)
5) continue through the paravertebral ganglia without synapsing.
6) they continue through splanchnic nerves until they reach a prevertebral/preaortic ganglia (located proximally to their target organ).
7) synapse with their postganglionic neuron.
8) The postganglionic nerve then proceed to innervate their targets (pelvic visceral organs)
Compare/Contrast: Parasym. and Sym.
Nothing to do w/ body wall structures
Don’t travel on spinal nerves (splanchnic nerves: go to body cavity)
Come out, get in chain, synapse, follow spinal nerve to target
Innervates body wall
Travel on spinal nerves
The only cranial nerve carrying parasympathetics that we will see this semester is the (blank).
Only innervates viscera in body cavities, glands in the head, the eye and erectile tissues.
Where do sympathetics originate?
How do they exit the cord?
Where can they synapse?
How do they reach their targets?
Lateral horn. (intermediate gray)
On the ventral root.
In the chain (paravertebral) or prevertebral ganglia. Tend to have shorter preganglionics and longer post than the parasympathetics
On splanchnic nerves, spinal nerves or blood vessels.
Sympathetic = (blank) effect
Parasymp = (blank effect)
1) Global (fight or flight)
The lateral horn has the greatest # of cells in the (blank) region.
ganglia and pre-
and post ganglionic
fibers that lie
along side of the
vertebral bodies; runs the
entire length of the
despite the fact that
come from the T1-
arise from the chain
and travel (blank).
are connected between the chain and spinal nerve, so they run (blank).
Presynaptic sympathetic fibers have the option of passing through or synapsing at ganglia anywhere within what structure?
Presynaptic sympathetic fibers can either synapse in the sympathetic chain or in preaortic ganglia in the abdomen (or the suprarenal medulla).