Anatomy - autonomic nervous system - intro
Terms
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- Visceral efferent fibers
- motor fibers, innervate involuntary (smooth) muscle, in the walls of organs and blood vessels, modified cardiac muscle, glands
- Visceral afferent fibers
- provide information about bodys internal environment, regulate BP and blood chemistry by altering heart rate, respiratory rate, vascular resistance, also pain
- Name two divisions of autonomic system
- Sympathetic (thoracolumbar) and Parasympathetic (craniosacral)
- Where is the cell body of preganglionic neuron located?
- Gray matter of CNS
- Where do preganglionic fibers terminate
- On postganglionic neuron
- Where are the cell bodies of postganglionic neuron located?
- Autonomic ganglia outside CNS
- Where do postsynaptic fibers terminate?
- On effector organ (smooth muscle, cardiac muscle, glands)
- Which NT is used by sympathetic system?
- NE (except sweat glands)
- Which NT is used by parasympathetic system
- Ach
- Name two roots of spinal nerve
-
Ventral - efferent
Dorsal-afferent - Name two branches of spinal nerve
- Ventral and dorsal rami, carry both motor and sensory fibers
- What does dorsal ramus innervate
- Synovial joints of the vertebral column, deep muscles of the back, overlying skin
- What does ventral ramus innervate
- Anterior and lateral regions of the trunk, upper and lower limbs
- GSA fibers
- General somatic afferent, transmit sensations from body to CNS - pain, touch, temp, proprioceptive info from muscles, tendons, joints.
- Dermatome
- Unilateral area of skin innervated by general sensory fibers of a single spinal nerve
- Why doesnt lesion of single spinal nerve result in paralysis
- General sensory fibers conveyed by adjacent spinal nerves overlap almost completely as they are distribute to skin, providing double coverage
- GSE
- General somatic efferent, transmit impulses to skeletal muscles
- Myotome
- Unilateral muscle mass receiving innervation from the somatic motor fibers conveyed by single spinal nerve
- GVA
- General visceral afferent, transmit pain or subconscious visceral reflex sensations from hollow organs, glands and blood vessels to CNS
- Name location of cell bodies of sensory fibers
- Both visceral and general sensory fibers have their cell bodies in spinal ganglia or ganglia of cranial nerves
- GVE
- transmit impulses to involuntary muscle and glandular tissue
- IML
- Lateral horns, location of preganglionic neurons of sympathetic division of ANS, located between T1-L2 segments of spinal cord
- Name location of sympathetic postganglionic cell bodies
-
Paravertebral ganglia - form sympathetic chains on each side of vertebral column
Prevertebral ganglia - plexuses surrounding origins of abdominal aorta - How do axons of preganglionic neurons leave spinal cord
- Through ventral roots and enter ventral rami of spinal nerves T1-L2, then pass to sympathetic chain through white rami communicantes (WRC)
- What are 4 possible courses preganglionic fibers can take within sympathetic chain
-
1) ascend
2)descend and synapse there
3)synapse at same level it was
4) not synapse at all, and continue through splanchnic nerve to reach prevertebral ganglia - Which preganglionic nerves would follow first three routes
- Nerves that innervate head, neck, body wall, limbs and thoracic cavity
- Which pregnaglionic nerves would follow last route?
- Nerves innervating viscera of abdominopelvic region
- How do postganglionic fibers travel
- They pass from paravertebral ganglia of sympathetic chains to adjacent ventral rami of spinal nerves through grey rami communicantes
- Which spinal nerves get postganglionic fibers
- All 31
- Splanchnic nerve
- Convey visceral efferent and aferent fibers to and from viscera of the body cavities
- Name location of preganglionic parasympathetic cell bodies
-
CN III, VII, IX, X
S2-S4 segments of spinal cord