Nervous System - Autonomic Nervous System Flashcards
Where does the visceral nervous system collect information from?
- within the body
- Internal organs
Where does the Visceral Nervous System distribute motor impulses?
- Glands
- Muscles of internal organs
What is different about the pathway between the Somatic Nervous System and the Visceral nervous system?
Somatic - Fast pathway - myelinated neuron - one neuron from the CNS to target Visceral - Slow pathway - Unmyelinated Neuron - Ganglion between CNS and target organ
What is the Autonomic Nervous System?
- The motor component of the visceral nervous system
What are the two major subsections of the Autonomic Nervous System?
- Sympathetic Nervous System (fight of flight)
- Parasympathetic Nervous System (rest and digest)
Where does the Sympathetic Nervous System originate from?
- Lateral Horn of T1-L2 Segments of the Spinal Cord
Where does the Parasympathetic Nervous System originate from?
- Brainstem and Spinal Cord
What are the pre & post-ganglionic Neurons? Where do they synapse?
Preganglionic Neurons - Primary Cell Bodies Postganglionic Neurons - Secondary Cell Bodies Synapse - The Ganglions
Do both Autonomic Nervous Systems have Pre/Postganglionic neurons?
- Yes
Do all fibers that enter the Ganglion Synapse there?
- No, some just pass through
Where does the Sympathetic Nervous System originate from and where can their neurons synapse?
Originate
- T1-L2 lateral horns (primary sympathetic neurons)
Synapse
- Para-vertebral Ganglia (secondary Sympathetic Neurons)
- Pre-vertebral Ganglia (secondary Sympathetic Neurons)
What is the structure of the Para-vertebral Ganglia?
- Continous chain (sympathetic chain or trunk)
- located on each side of the spinal cord
- Starts at either side of the neck
- Connects at end of vertebral column at coccyx region
What does the most superior region of the para-vertebral ganglia form?
- cervical ganglions which supply the head and neck
How do Para-vertebral ganglia communicate with the spinal nerves?
- White Ramus Communicans
- Grey Ramus Communicans
Describe the Pathway of the White Ramus Communicans. Myelinated?
- Carries preganglionic sympathetic fibers from the lateral horn (ventral root) to
- Spinal Nerve (ventral Ramus) to
- the Paravertebral Ganglion
Myelinated
Describe the pathway of Gray Ramus Communicans. Myelinated?
- takes the postganglionic neuron out of the paravertebral ganglia
- to the spinal nerve
- to the target organ (head and neck, upper limbs, thorax, and lower limbs)
- unmyelinated*
What are the Pre-Vertebral Ganglia?
- Secondary Sympathetic Neurons
- Found in the abdomen in front of the vertebral column
- Synapse location for preganglionic fibers that do not synapse in the sympathetic chain (paravertebral ganglia)
What is a splanchnic nerve?
- a preganglionic fiber that does not synapse in the paravertebral ganglia
- synapses in the prevertebral ganglions
What does the neurons from the prevertebral ganglia supply?
- abdominal viscera
- pelvic viscera
Where does the parasympathetic nervous system originate and how does it interact with organs?
Originates
- Brainstem or the Sacral S2-S4 sections
Interact
- Preganglionic fibers go directly to the target organ or ganglia very close to it (visceral ganglion)
What is the difference between the Pre/Postganglionic fibers and ganglion of the Parasympathetic and Sympathetic Nervous Systems?
Parasympathetic - Preganglionic Fibers: Longer - Postganglionic Fibers: Shorter - Ganglion: only Visceral (located close to target organ) Sympathetic - Preganglionic Fibers: Shorter - Postganglionic Fibers: Longer - Ganglion: 2, Paravertebral and Prevertebral, located beside and in front of the vertebral column respectively.
What 4 Cranial Nerves have Parasympathetic Nuclei? Where are they located?
Cranial Nerves - CN III: oculomotor nerve - CN VII: Facial Nerve - CN IX: Glossopharyngeal Nerve - CN X: Vagus Nerve Location - Brainstem
Where do the Facial, Oculomotor, & Glossopharyngeal Cranial Nerves provide parasympathetic nerves?
- The Head and Neck
Where does Cranial Nerve III supply parasympathetic nerves?
Oculomotor Nerve:
- Targets the constrictor muscles of the iris, causing miosis (constriction)
