Nervous System Flashcards
Nervous system tree
CNS –>
PNS –> (Sensory, Motor (Somatic, Autonomic (Sympathetic, Parasympathetic) ) )
How many pairs of spinal nerves are there? What does each spinal nerve contain?
31 pairs. Each spinal nerve contains both motor and sensory fibers
What is the organization of spinal nerves? (Name and number)
8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal
How many pairs of cranial nerves are there?
12 pairs
Where do dorsal root ganglia cell bodies derive from?
Neural crest
Where are the cell bodies for ventral root neurons and where did they derive from?
They are in the ventral region of spinal grey matter and they derived from neural tube
How many paravertebral ganglia are there on each side of the spinal cord?
31 paravertebral ganglia
How many white and grey rami communicans are there on each side of the spinal cord?`
14 white and 31 grey rami communicans
If an axon travels via white rami communicans to a paravertebral ganglia but doesn’t synapse, then goes out to viscera, where will it synapse?
A prevertebral ganglia
What are the five important sympathetic preganglionic splanchnic nerves we need to remember?
Greater, lesser, least, lumbar, and sacral
In what prevertebral ganglia does each of the five sympathetic preganglionic splanchnics synapse?
Greater: celiac ganglion Lesser: superior mesenteric ganglion Least: aorticorenal ganglion Lumbar: inferior mesenteric ganglion Sacral: hypogastric plexus
What are the origin fibers of the splanchnic nerves?
Greater: T5-T9
Lesser: T10-T11
Least: T12
What is the acronym for the functions of the parasympathetic system?
SLUDD (salavation, lachrymation, urination, digestion, and defecation)
Where do parasympathetic nerves leave the spinal cord and where do they synapse?
They leave via 1 of 4 cranial nerves or via sacral spinal cord segments S2-S4. They synapse in terminal ganglia near their end organs.
The vagus nerve: what CN # is it and what does it innervate?
It is CN X, and it innervates many viscera including the heart, lungs, and the walls of the fore- and midgut of the GI tract
Visceral afferent nerves that convey pain normally course with ________ nerves. Visceral afferents that convey physiologic sensations other than pain course with _______ nerves.
Visceral afferent nerves that convey pain normally course with sympathetic nerves. Visceral afferents that convey physiologic sensations other than pain course with parasympathetic nerves.
Most sympathetic nerves enter the CNS between which two spinal nerves?
T1 and L2
Since most visceral pain fibers course w/ sympathetic nerves to enter the CNS, most visceral pain is referred to which dermatomes?
T1 through L2
Sympathetic postganglionic splanchnics: where do they originate and what do they innervate?
These are the cardiopulmonary splanchnics. Their presynaptic fibers arise in T1-T4, and they synapse in the upper thoracic and lower cervical ganglia, then immediately exit the sympathetic chain to innervated the larynx, trachea, bronchi, lungs, and heart
Sympathetic preganglionic splanchnics: where do they originate and what do they innervate?
They originate between T5 and the lower lumbar nerves, and they innervate all many viscera in the abdomen and pelvis
Parasympathetic preganglionic splanchnics: where do they originate and what do they innervate?
They leave the spinal column via S2-S4 nerves and travel straight to their destination, where they synapse in intrinsic ganglia. They innervate the descending and sigmoid colon, rectum, and pelvic viscera.
They should technically include the vagus nerve, which is CN X and innervates cardiopulmonary system, foregut, and midgut
Parasympathetic postganglionic splanchnics: where do they originate and what do they innervate
NADDA: they don’t exist
What innervates the deep back muscles, joints between vertebrae, and the skin of the medial 2/3 of the back?
dorsal ramus
What is the name for a collection of cell bodies in the PNS?
ganglion
What is the name for a collection of cell bodies in the CNS?
nucleus
What is the name for a nerve containing autonomic fibers (usually but not necessarily preganglionic) and visceral sensory fibers that supply the viscera?
splanchnic nerve
A bundle of axons inside the CNS
tract
An intertwining of ventral rami of spinal nerves
plexus
This contains axons of motor neurons only
ventral root
cranio-sacral portion of the autonomic nervous system
parasympathetic
This carries preganglionic sympatheti axons from the ventral ramus of a spinal nerve into the sympathetic paravertebral chain
white ramus communicans
Axons from ganglia situated in or near the walls of viscera they innervate
postganglionic parasympathetic fibers
Neurons whose cell bodies are in the lateral horn of the grey matter of the spinal cord. Their axons travel in the ventral roots, ventral rami, and white rami communicantes
preganglionic sympathetic fibers
This division of the PNS innervates arrector pili muscles, vascular smooth muscle, and sweat glands of skin.
sympathetic nervous system
