Nervous System - Autonomic Nervous System Flashcards
What is the motor part of the somatic nervous system concerned with?
Innervation of skeletal muscle.
What does autonomic control?
- Involuntary functions.
- Visceral motor.
- Visceral sensory.
What makes up the peripheral nervous system?
- Somatic.
- Autonomic.
What does somatic control?
- Somatic sensory fibres.
- Somatic motor fibres.
- Voluntary actions.
Where are the cell bodies in the somatic nervous system?
- Motor nuclei of cranial nerves.
- Anterior horn cells of the spinal cord.
How is the nervous system broken up?
- Central nervous system.
- Peripheral nervous system.
Where do the nerve fibres go in the somatic nervous system?
Run un-interrupted straight to the muscles, ending as end plates of th muscle fibres.
What is the motor part of the autonomic nervous system concerned with?
Innervation of cardiac and smooth muscle and glands.
What is the pathway for nerves in the autonomic system?
The nerves are classically interrupted by synapses in a ganglion.
What is pre-ganglionic and post-ganglionic autonomic fibres?
This is when there are two nerves in the autonomic nervous system that are broken up by synapses in ganglions.
Where do the preganglionic cell bodies lie?
Within the central nervous system.
Where do sympathetic preganglionic cell bodies lie?
Lateral horn cells of all thoracic and upper two lumbar segments of the spinal cord - thoracolumbar outflow.
Where do parasympthetic preganglionic cell bodies lie?
Certain cranial nerve nucle in and in lateral horn cells of sacral segments of the spinal cord - craniosacral outflow
Where do postganglionic cell bodies lie?
Peripheral nervous system.
Where do sympathetic postganglionic cell bodies lie?
- Sympathetic trunk - paravertebral ganglia.
- Collateral ganglia e.g. coeliac ganglia.
Where do parasympathetic postganglionic cell bodies lie?
Terminal ganglia - within the walls of viscera OR in four ganglia (head and neck).
What are the outcomes when preganglionic fibres have reached the sympathetic trunk?
- Synapse with cell bodies in a trunk ganglion.
- Leave the trunk ganglion without synapsing and to pass to a collateral ganglion for synapse.
- leave the trunk without synapsing and pass to the suprarenal gland, where certain cells of the medulla can be regarded as modified ganglion cells (small number of cells).
Where will you not find sympathetic outflow?
- Cervical part of the cord.
- Lower lumbar and sacral parts.
Where do the preganglionic fibres go to where there is no sympathetic flow?
These fibres ascend in the sympathetic trunk to cervical ganglia, and lower lumbar/sacral nerves descend in the trunk to lower lumbar and sacral ganglia.
What are the spinal levels of sympathetic preganglionic cells that supply the heart?
T1-5.
What are the spinal levels of sympathetic preganglionic cells that supply the upper limb?
T1-6.
What are the spinal levels of sympathetic preganglionic cells that supply the head salivary glands?
T1-3.
What are the spinal levels of sympathetic preganglionic cells that supply the eye?
T1-2.
What are the spinal levels of sympathetic preganglionic cells that supply the oeosphagus?
T4-6.
What are the spinal levels of sympathetic preganglionic cells that supply the lungs?
T2-6.
What are the spinal levels of sympathetic preganglionic cells that supply the stomach/liver/gallbladder/pancreas?
T7-9.
What are the spinal levels of sympathetic preganglionic cells that supply the small gut?
T9-10.
What are the spinal levels of sympathetic preganglionic cells that supply the appendix/colon?
T10-11.
What are the spinal levels of sympathetic preganglionic cells that supply the gonads?
T10-11.
What are the spinal levels of sympathetic preganglionic cells that supply the supra-renal?
T10-L1.
What are the spinal levels of sympathetic preganglionic cells that supply the lower limb
T11-12.
What are the spinal levels of sympathetic preganglionic cells that supply the bladder/rectum/uterus?
T12-L2.
What are the spinal levels of sympathetic preganglionic cells that supply the kidney?
T12-L1.
What are the spinal levels of sympathetic preganglionic cells that supply the ureter?
L1-2.
Where does the sympathetic trunk extend?
Alongside the vertebral column from the base of the skull to the coccyx. This theoretically forms a ganglion for each nerve.
Describe the ganglions and fusion?
Fusion occurs classically in the cervical region:
1. Upper four ganglion form = superior cervical ganglion.
2. 5-6th ganglion form = middle cervical ganglion.
3. 7-8th ganglion form = inferior cervical ganglion.
There is usually one ganglion less than the number of nerves e.g. 11 thoracic.
Where do the fibres from the lateral horn cells of each segment leave?
Anterior nerve root - with the axons of the anterior horn cell. They go to reach the spinal nerve and its anterior ramus.
What are rami communicantes?
Connecting links to the sympathetic trunk and its ganglia.
What are the type of rami ocmmunicantes?
- White ramus communicans.
- Grey ramus communicans.
Describe the features of the white ramus communicans?
- More distal of the two fibres.
- Contains preganglionic fibres (myelinated - so called white).
Describe the features of the grey ramus communicans?
- More proximal of the two fibres.
- Contains post-ganglionic fibres (unmyelinated).
How are the fibres in the grey ramus communicans distributed?
Via the branches of the spinal nerve to the following structures:
- Blood vessels.
- Sweat glands.
- Arrector pili muscles (vasomotor, sudomotor, pilomotor).
What does every spinal nerve receive?
Grey ramus.