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Does the gray rami communicans contain fibers of a preganglionic or postganglionic neurons?
could be preganglionic
Why are postganglionic axons unmyelinated?
Postganglionic axons are unmyelinated primarily because they are typically shorter and have slower conduction velocities compared to myelinated fibers. The myelination process requires significant metabolic resources, and since postganglionic axons generally transmit signals over shorter distances, the energy cost of myelination is not justified. Additionally, unmyelinated fibers are often involved in the modulation of involuntary functions, where slower transmission speeds are adequate for their role in the autonomic nervous system.
Which division of the autonomic nervous system is characterized by short preganglionic and long postganglionic fibers?
The parasympathetic nervous system has long preganglionic and short postganglionic fibers
Are parasympathetic postganglionic fibers generally come from adrenergic fibers?
No, parasympathetic postganglionic fibers do not come from adrenergic fibers. Parasympathetic postganglionic fibers release acetylcholine as their neurotransmitter, whereas adrenergic fibers release norepinephrine.
The parasympathetic nervous system is characterized by peripheral ganglia is usually near?
organs and by short postganglionic fibers
What parasympathetic ganglion sends postganglionic fibers to the sublingual and submandibular salivary glands?
The submandibular ganglion sends postganglionic fibers to the sublingual and submandibular salivary glands.
Are unmyelinated cortical fibers found in the cerebral hemispheres?
Yes, unmyelinated cortical fibers can be found in the cerebral hemispheres. These fibers are a type of nerve cell projection that lack the protective myelin sheath, which is typically found in myelinated fibers. Unmyelinated fibers are involved in transmitting nerve impulses and can be found throughout the brain, including the cerebral hemispheres.
Postganglionic axons secrete acetylcholine cholinergic fibers?
Parasympathetic
What is innervated by postganglionic fibers arising from the cervical ganglia?
the eyes
What releases catecholamines as a neurotransmitter?
it would be postganglionic sympathetic fibers
Which nerve fiber do impulses travel slowly?
Unmyelinated nerve fibers conduct impulses more slowly than myelinated nerve fibers. Myelinated nerve fibers have a fatty substance called myelin sheath that allows for faster transmission of impulses compared to unmyelinated fibers without this sheath.
Why speed of unmyelinated nerve fibre is more than myelinated nerve fibre when diameter is small?
The speed of unmyelinated nerve fibers can sometimes exceed that of myelinated fibers when the latter have a smaller diameter because conduction velocity in unmyelinated fibers is influenced by their ability to propagate action potentials continuously along their length. In smaller-diameter myelinated fibers, the presence of myelin can create a higher resistance, which can slow conduction. However, as fiber diameter decreases, the benefits of myelination (such as saltatory conduction) may not compensate for the increased resistance, allowing some unmyelinated fibers to conduct impulses more rapidly. Thus, in specific cases, unmyelinated fibers can outpace smaller myelinated fibers due to these factors.
