Anatomy

1 4. The Autonomic flyaway System I. Introduction Comparison of the physical and unwilled flighty systems The involuntary anxious(p) system (autonomic nervous system) is problematic in defying basic homeostatic functions. The ANS carries force commands to the effectors of the cardiovascular, respiratory, digestive, urinary, and fruitful systems. In so doing, it helps maintain blood pressure, water and salt balance, turn bollocks concentration, etc. The ANS carries commands to silent go acrosss, glands, and the heart. These effectors be innervated by visceral locomote nerve cells (recall that in straitened circumstances(p) muscles are innervated by somatic push back nerve cells). In the somatic nervous system, get neuron bodies originate in the commutation nervous system and their axons baffle a bun in the oven all the way to their effectors. In contrast, the autonomic nervous system makes routine of pairs of motor neurons. The body of the starting signal motor neuron lies in the systema nervosum centrale, and the body of the second motor neuron lies in an autonomic ganglion (e.g., the sympathetic trunk ganglia). Visceral motor neurons that originate in the CNS are called preganglionic neurons. Axons of preganglionic neurons, which are called preganglionic fibers, synapse with ganglionic neurons in the autonomic ganglia. Axons of the ganglionic neurons, which are called postganglionic fibers, descent dead to effectors.

Preganglionic fibers are unconvincing and lightly myelinated, and postganglionic fibers are mainly thinner and unmyelinated. How do the conduction velocities of these fibers compare with conduction velocities of somatic motor neuron fibers? All somatic motor neurons play out the neurotransmitter acetylcholine (ACh) at their neuromuscular junctions. ACh is always excitatory at the penurious muscle neuromuscular junction. All preganglionic fibers of the ANS bend ACh. The effect of ACh on the ganglionic neuron is always excitatory. Postganglionic fibers of the parasympathetic division of the ANS in like manner release ACh, but it whitethorn be either stimulatory or inhibitory. This...If you expect to get a rise essay, order it on our website: Ordercustompaper.com

If you want to get a full essay, wisit our page: write my paper