Lecture 8: Autonomic Nervous System Flashcards
How is sensory information (AP) carried to the CNS from the periphery?
Afferent neurons
How is motor information (AP) carried from the CNS out to the periphery?
Efferent neurons (motorneuron)
At the simplest level, the nervous system functions in a series of ________.
Reflex arcs
What occurs first when you touch a hot stove?
Nociceptors in hand are brought to threshold and an AP travels down the nerve to the spinal cord.
What occurs at the spinal cord after you touch a hot stove?
- The AP depolarizes the pre-synaptic membrane of the axon from nociceptors.
- The efferent neuron is brought to threshold by the epsp’s
What occurs from the spinal cord out to the hand during the withdraw reflex?
An AP travels through the (alpha)-motorneuron out to the hand activating the skeletal muscle.
What takes the place of the efferent neuron (motorneurons) in the autonomic reflex arc?
Autonomic nervous system
How is the stimulus coming through the afferent neuron different for the autonomic nervous system?
Are often much broader stimuli, and many times are afferents within the viscera
In the reflex arc what is more important for function, spinal cord or brain?
The spinal cord, don’t actually need a brain for this reflex.
Where does the majority of the integration of autonomic reflex occur? (Be specific)
Within the brain, more specifically the lower levels (brainstem and hypothalamus)
The outflow of the ANS has how many neurons in series going to the effector cell?
Two neurons
What is a ganglion?
Collection of cell bodies outside of the CNS
Where does the pre-ganglionic axon synapse on the post-ganglionic neuron?
The ganglion
Where does the post-ganglionic neuron travel?
To the target organ where it synapses
Where do the axons of the parasympathetic pre-ganglionic axons leave the CNS?
- Cranial region
- Sacral region
Where are the ganglia of the parasympathetic nervous system located?
On or near the target organ
What are lengths of the parasympathetic pre- and post-ganglionic fibers?
Pre-ganglionic = long
Post-ganglionic = short
Where do the axons of the sympathetic pre-ganglionic axons leave the CNS?
- Thoracic region
- Lumbar region
Where are the ganglia of the sympathetic nervous system located?
The sympathetic chain, just outside the vertebral column
What are lengths of the sympathetic pre- and post-ganglionic fibers?
Pre-ganglionic = short
Post-ganglionic = long
In the parasympathetic and sympathetic nervous system what is the NT released by the pre-ganglionic fiber and what receptor does it bind to?
ACh is released and binds to a nicotinic AChR on the post-ganglionic cell membrane.
What occurs when ACh binds to the nAChR on the post-ganglionic cell membrane?
- nAChR is a ligand-gated sodium channel
- Sodium enters the dendrite causing an epsp and eventually an AP
What NT is released by the post-ganglionic cell in the parasympathetic nervous system?
ACh
What is the efferent synaptic structure in the autonomic nervous system? (She uses a specific analogy here)
These synapses are en passant (in passing)
*Like the mailman throwing your mail out of the window as/he she goes by your house…
