Lecture 17 : Functional Information Flow Flashcards
What are the two types of signals transmitted from the nervous system?
Somatic, the stuff we have control over.
Autonomic, the stuff we are not aware of, have no control over.
Give an example of somatic efferent and somatic afferent.
Efferent - voluntary muscle control.
Afferent - what we see
Give an example of autonomic efferent and afferent.
Efferent - involuntary muscle control.
Afferent - Sensory information we don’t know about (blood pressure)
How many neurons are between the brain and effector in the somatic efferent (motor) division?
Two neurons between brain and effector.
Upper motor neuron - cell body in brain, axon in spinal cord. Fully in CNS
Lower motor neuron - cell body in spinal cord axon in spinal nerve. Cell body in CNS and axon in PNS.
Are the axons in the somatic efferent (motor) division myelinated or not? Why?
Both axons are myelinated in order to improve the conductive velocity of the electrical signal which travels along the axon. The axon in the CNS was myelinated from oligodendrocytes while the axon in the PNS was myelinated from Schwann cells.
What is the neurotransmitter released at the synaptic cleft in the somatic efferent (motor) division?
Acetyl Choline.
What are the two divisions of the autonomic efferent system?
Sympathetic and Parasympathetic.
How many neurons are between the brain and effector in the autonomic efferent (motor) system?
Three neurons. Neuron One, cell body in brain axon in brain or spinal cord. Neuron Two, cell body in brain or spinal cord axon in PNS. Neuron Three, cell body in PNS axon in PNS.
Is neuron two or neuron three in the autonomic efferent system myelinated? Why? (think of diameter)
Neuron two is myelinated, neuron three is not. This is because the axon of neuron three has a small diameter. Axons with small diameter don’t conduct faster whether they are unmyelinated or not, hence why postganglionic neuron do not have myelinated axons.
What neurotransmitter is released between neuron 2 and neuron 3 of the autonomic efferent system?
Acetyl Choline.
What neurotransmitter is released between the postganglionic neuron and the effector in the autonomic efferent system?
Acetyl Choline or norepinephrine.
Where are the structural differences of the parasympathetic division and the sympathetic division found? What are they?
On neurons two and three.
In both divisions the preganglionic neuron is myelinated however in the sympathetic division this axon is short and the post ganglionic neuron’s axon is long. While in the parasympathetic division this axon is long and the post ganglionic neuron’s axon is short.
Secondly, the sympathetic nervous system releases Norepinephrine as its neurotransmitter and the parasympathetic system releases acetyl choline.
Where is the location of the preganglionic neuron’s cell body in the CNS? Sympathetic
Thoracolumbar (spinal cord T1 to L2)
Where is the location of the preganglionic neuron’s synapse to the postganglionic neuron? Sympathetic
Sympathetic Chain or Collateral Ganglion.
Where is the location of the preganglionic neuron’s cell body in the CNS? Parasympathetic
Craniosacral (brainstem and sacral spinal cord)
