Anatomy of the ANS Flashcards
Pelvic Splanchnics
- Hindgut and pelvic organs
- Lateral horn of S2-S4
- Exit via ventral rami
Vagus Nerve and Vagus Nerve Pathway
Thoracic organs, abdominal organs − Foregut thru midgut
Terminal ganglia found in walls of organs
Typical Spinal Nerve
Visceromotor effector organs dependence on ANS nerves
- Visceromotor effector organs do not need the ANS to function
- If the autonomic nerves are cut the organ will not work as well
- – Pacemaker cells have intrinsic beat of 100 bpm
- – Parasympathetic lowers rate to 70- 80bpm
Splanchnic Nerves
- Ultimate target is to organs
- Exit anteriorly from sympathetic chain
- Named after part of chain (thoracic, lumbar, etc )
Collateral Ganglia and Autonomic Plexuses
- AKA prevertebral
- Anterior surface of aorta
- Postganglionic cell bodies
- Found in thorax and abdomen
- Autonomic plexuses follow blood vessels to their destinations
Sympathetic Pathway Patterns
Sympathetic Pathway to Thoracic Organs
Targets: heart and lungs
ASCEND in chain to cervical levels
T1-T6
cervical splanchnic nerve
to cardiopulmonary plexus
Sympathetic Pathway to Adrenal Medulla
T8-L1
Target: chromaffin cells
Sympathetic Chain
- AKA sympathetic trunk
- Runs length of vertebral column
- Sympathetic chain ganglia have postganglionic cell bodies
Sympathetic Pathway to Skin and Limbs
Targets: Sweat glands, arrector pili muscles and blood vessels
Sympathetic Pathways Summary
Destinations, Entrance, route in chain, exit, postganglionic cell bodies
Sympathetic Division of ANS
“Thoraco-lumbar”
Preganglionic cell bodies located from T1-L2
Lateral horn of gray matter
Parasympathetic Division
- “Craniosacral”
- − Brainstem
- − Lateral horn of sacral spinal cord levels 2, 3 and 4
- − Organs only
- − Terminal ganglia
- Near target organ or in organ wall
Communicating Rami of Sympathetic Chain
White − IN to the sympathetic chain − Preganglionic fibers only − T1-L2 only
Gray − OUT of the sympathetic chain − Postganglionic fibers only − All spinal nerves
ANS divisions summary chart: sympathetic vs. parasympathetic
origin, destination, fiber length, location of ganglia, divergence, postganglionic neurotransmitter
Identify:
right vagus
left vagus
esophageal plexus
anterior vagal trunk
cardopulmonary plexus
Targets of the Autonomic Nervous System
- cardiac muscle
- glands
- smooth muscle
Types of Information in the Nervous System
Somatic (Limbs and Skin)
- motor (outgoing)
- sensory (incoming)
Visceral (organs and glands)
- motor (outgoing) – visceromotor (autonomic)
- sensory (incoming)
Comparing Somatic Motor Innervation to Autonomic Innervation: control, target, pathway, myelination, effect
Parasympathetics in the Head
SNS vs PSNS :
Origin Destination Fiber length Location of ganglia Divergence Neurotransmitter
Identify:
Ventral Ramus
Communicating Rami
Sympathetic Chain Ganglion
Sympathetic Chain
Greater Thoracic Splanchnic Nerve
Autonomic Dysreflexia
a syndrome in which there is a sudden onset of excessively high blood pressure. It is more common in people with spinal cord injuries that involve the thoracic nerves of the spine or above (T6 or above).
Blood pressure remains elevated until noxious stimulus removed
Emergency treatment necessary
Sympathetic Pathway to Abdominal Organs
T5-T12
Targets: digestive system, liver, kidneys
Greater (T5-T9) Lesser (T9-T10) Least (T12)
