Autonomic Physiology Flashcards
Where do parasympathetic fibers exit the CNS?
Cranial and Sacral
Where do sympathetic fibers exit the CNS?
Thoracic and Lumbar
What is the location of ganglia for Sympathetic and Parasympathetic fibers, respectively?
Sympathetic Chain (sympathetic)
On/near the target organ (parasympathetic)
Parasympathetic presynaptic axons are (LONG/SHORT) and the postsynaptic axons are (LONG/SHORT).
Long (must travel to ganglion on target organ)
Short
Sympathetic presynaptic axons are (LONG/SHORT) and the postsynaptic axons are (LONG/SHORT).
Short (must travel to sympathetic chain, just outside spine)
Long
Explain a reflex arc involving skeletal muscle.
Sensory (afferent) information is received, especially from pain fibers (i.e., burning your hand). The sensory information is then relayed to the CNS, in this case the Spinal Cord. The sensory fibers will synapse at a NMJ with the motor neuron that innervates the skeletal muscles (in this case, the hand) to move that particular body part.
In an autonomic reflex arc, the afferent (sensory) neuron and its information can be the same as things that elicit other reflexes. However, instead of relaying its information to the Spinal Cord, it is sent to…
Brain – particularly the Hypothalamus
What type of neuron will relay the signal to skeletal muscle?
Alpha Motor Neuron
For autonomic reflexes, this takes the place of the Alpha Motor Neuron.
Autonomic Nervous System
In the somatic motor system, there is ______ neuron(s) between the CNS and the target organ. In the autonomic nervous system, there is ______ neuron(s) between the CNS and the target organ.
One
Two
In the ANS, the pre-synaptic neuron (cell body in the CNS) will terminate in a _________ in the periphery. From here, the post-synaptic neuron will go to the target organ.
Ganglion
In the ANS, where do the cell bodies of the pre-synaptic and post-synaptic neurons lie?
Pre-synaptic – Cell body in CNS
Post-synaptic – Cell body in ganglion
In the ANS, how many synapses are there between the CNS and the target organ?
Two synapses –
1) In the ganglion
2) At the target organ
T/F. In the ANS, the synapse in the ganglion varies greatly between the sympathetic and parasympathetic systems.
False. The synapse is essentially the same between sympathetic and parasympathetic systems. Both use ACh and nAChR.
The pre-ganglionic axon (from CNS) releases __________ at its synapse between the pre- and post-ganglionic neurons (in the ganglia).
Acetylcholine (ACh)
In the ganglia, the post-ganglionic cell expresses what kind of receptor at its post-synaptic membrane?
Nicotinic Cholinergic Receptors (nAChR)
T/F. The second synapse, at the end organ, is different in the sympathetic and parasympathetic systems.
True
Explain the histology of the pre-synaptic component of the second synapse in the ANS.
Varicosities contain all the components of the pre-synaptic terminal (vesicles of neurotransmitters, mitochondria, etc.) and work exactly the same way as the pre-synaptic terminal of the NMJ.
Explain the histology of the post-synaptic component of the second synapse in the ANS.
The post-synaptic side has ligand-gated receptors that are not concentrated opposite the pre-synaptic terminal like in the NMJ. Instead, they are more spread out all over for the neurotransmitter to diffuse.
- **NMJ – mail in mailbox (SPECIFIC)
- **Varicosities – mail thrown in yard (NOT SPECIFIC)
What is the neurotransmitter released from the post-ganglionic axon (from ganglionic synapse) to the target organ?
ACh
