Autonomic NS :( Flashcards
What is the autonomic nervous system?
A component of the peripheral nervous system which controls involuntary processes.
What does the ANS control?
Smooth muscle in the following:
-blood vessels
-airways
-bladder
-eyes
-gut
-sex organs.
Also controls cardiac muscles and glands (salivary and sweat).
Name the three subdivisions of the ANS.
Sympathetic NS
Parasympathetic SN
Enteric NS
Where are the cell bodies of motor units found?
In the dorsal horn of the spinal cord.
Describe the role of motor units in the somatic nervous system.
Send axons through the ventral root all the way to the periphery where they meet their target- skeletal muscle.
In the ANS, how many fibres are used to get the axons to their target?
2
What is the ganglion?
Collection of neuronal cell bodies
Name the fibre before and after the ganglion in the ANS.
Before= pre-ganglionic fibre
After= post-ganglionic fibre
Briefly describe the structure of the pre-ganglionic fibre and the post-ganglionic fibre.
Pre-ganglionic fibre=small myelinated
Post-ganglionic fibre=unmyelinated
p.s. Myelinated axons are the neuron axons which are covered with myelin sheaths. Unmyelinated axons are the axons which are not covered with myelin sheaths.
List the different targets for the post-ganglionic fibres.
Smooth muscle, glands, cardiac muscle and GI neurons.
What is the target for the autonomic NS?
Skeletal muscle
Name the synapses of the somatic NS.
Highly specialised neuromuscular junction.
What is an endplate potential?
The voltages which cause depolarization of skeletal muscle fibres caused by neurotransmitters binding to the postsynaptic membrane in the neuromuscular junction
Where are neurotransmitters released in the ANS?
In the interstitial fluid- will bump around until it finds it’s receptors.
One post ganglionic fibre can innervate how much tissue?
A large area of tissue.
What kind of receptors are found in the somatic NS?
Ionotropic receptors.
What kind of receptors are found in the autonomic NS?
Metabotropic receptors.
The second messenger used in the ANS can influence?
If the receptor will excite or inhibit the target.
Sympathetic=?
Fight or flight.
Para sympathetic=?
Rest and digest
Where is the outflow for the sympathetic division in the spinal cord?
Between T1 and L2.
Thoracic 1-12, Lumbar 1-2.
Short preganglionic fibres=?
Ganglia are v close to the spinal cord.
For the sympathetic division, what do the very long post ganglionic fibres lead to?
The targets
Where is the outflow for the parasympathetic diviosn?
The cranial and sacral region of the spinal cord (craniosacral).
Cranial I-XII
Sacral S1-5