Lecture 7 part one (SECOND MIDTERM) Flashcards
In an adult, one mesentery “goes away.” Which one is it?
Ventral mesentery
How many collections of axons?
2, and they go out into the peripheral nervous system
What is the “hole” inside of your spinal cord?
the central canal
Gray matter:
White matter:
Gray matter: gray because it contains bundles of cell bodies (nuclei) and they aren’t wrapped in myelin!
White matter: the area with bundles of axons (tracts)
Remember…
Bundles of cell bodies in the CNS:
Bundles of axons in the CNS:
cell bodies: nuclei
axons: tracts
Bundles of axons in the PNS:
nerves
When does it become a “nerve?”
When the dorsal portion and the ventral portion come together into a single bundle
What is the portion called that isn’t yet a nerve?
a root (dorsal root and ventral root)
Sensory information is brought into the spinal cord via what?
Dorsal roots
What contains the axons of motor neurons that extend into the periphery to control somatic and visceral effectors?
Ventral roots
Both of the sensory nuclei are inside of what?
both somatic and visceral are in the dorsal (posterior) gray horn
Where are the motor nuclei located?
in their OWN horns!
visceral: lateral gray horn
somatic: ventral (anterior) gray horn
What do the motor and sensory nuclei have in common?
The somatic nuclei are the most superficial compared to the motor nuclei
The only cells that are going to contribute to the ventral root are the ones that are in the ______________.
motor nuclei
*so you will only have motor or efferent axons in the ventral root!
The only ones communicating with the sensory nuclei are the axons traveling in the _____________.
dorsal root
*that means the dorsal root is only carrying sensory information by afferent axons!
What is a ganglion? Where?
collection/bundle of cell bodies in the PNS
What do the dorsal root ganglia contain?
cell bodies of sensory neurons
Dorsal root ganglion is a result of having what kind of neuron morphology?
(pseudo)unipolar neurons
A “mixed” spinal nerve is what?
They are spinal nerves that contain both afferent (sensory) and efferent (motor) fibers
The roots come together and form a ________, which then splits into a ____________ and a __________.
trunk
dorsal ramus and ventral ramus
In the adult cross-section, there is no longer a __________!!
Notochord (intervertebral discs)
What does the coelom separate?
visceral serosa from parietal serosa
Dorsal ramus division:
Ventral ramus division:
Dorsal: epaxial
Ventral: hypaxial
What root is associated with sensory and where are the cell bodies?
- Dorsal root
- Cell bodies are inside the dorsal root ganglia
What did Noriega say “fiber type” means?
Somatic afferent
Visceral afferent
Somatic efferent
Visceral efferent
Inside of the dorsal root, different ______ can be carried.
fibers
Autonomic nervous system is only to be considered…
motor
From the ventral ramus, what kind of information is going to be returned?
visceral sensory information; vessels and other unconscious structures of hypaxial region
From the dorsal ramus, what kind of information is going to be returned?
somatic sensory information; vessels, glands of epaxial region
Upper motor neurons are referring to:
CNS neurons; coming down from brain, running through spinal tracts, going into motor nuclei, synapse onto lower motor neurons
Lower motor neurons are referring to:
cell bodies in the CNS with axons that extend into PNS
For somatic efferent…
Upper motor neuron comes down into somatic efferent nucleus > synapse onto cell body > somatic efferent sends single out through ventral root (somatic efferent fiber) > into mixed spinal nerve > has access to epaxial or hypaxial regions
For visceral efferent…
AUTONOMIC NERVOUS SYSTEM!
-basically forget about upper motor neurons and refers to ANS as a 2 motor neuron system
The visceral efferent goes where?
Goes through the ventral root but goes DOWN through the “white communicating ramus” that communicated with an autonomic ganglion.
The autonomic ganglia are located…
near your vertebral bodies (actually form a pair of structures that go up and down your vertebral column) and its only for the SYMPATHETIC NERVOUS SYSTEM
What do we call the autonomic ganglia?
Sympathetic ganglia
Preganglionic:
Postganglionic:
Pre: white ramus
Post: gray ramus
The signal that goes to the sympathetic ganglia via the white ramus goes back to the mixed nerve via what?
the gray ramus
Where does the grey ramus go?
If it goes..
dorsal ramus: epaxial (unconscious)
ventral ramus: hypaxial (unconscious)
What happens if you send a signal to the sympathetic ganglion and it does NOT go to the hypaxial or epaxial regions?
The postganglionic neuron can go deeper inside the body and provide visceral efferent innervation to your thoracic organs (lungs, heart)
What happens if a preganglionic neuron travels through the ventral root, mixed spinal nerve, down the white communicating ramus and does NOT synapse inside of the sympathetic ganglion?
It will completely pass it and go all the way to a completely different sympathetic ganglion located inside of your abdominal cavity
