the effectors of the somatic nervous system are

The neurotransmitter released by the postganglionic neurons is noradrenaline (also called norepinephrine).

It stimulates action potentials in the postganglionic neurons. The neurotransmitter of the preganglionic sympathetic neurons is acetylcholine ( ACh). Here they synapse with the highly-modified postganglionic cells that make up the secretory portion of the adrenal medulla. However, some of these preganglionic neurons pass right on through this second ganglion and into the adrenal medulla. Here it may synapse with postganglionic sympathetic neurons running to the smooth muscular walls of the viscera.

leave the ganglion by way of a cord leading to special ganglia (e.g.

pass up or down the sympathetic chain and finally synapse with postganglionic neurons in a higher or lower ganglion.

synapse with postganglionic neurons (shown in white) which then reenter the spinal nerve and ultimately pass out to the sweat glands and the walls of blood vessels near the surface of the body.

The preganglionic neuron may do one of three things in the sympathetic ganglion: They pass into sympathetic ganglia which are organized into two chains that run parallel to and on either side of the spinal cord. The preganglionic motor neurons of the sympathetic system (shown in black) arise in the spinal cord. The autonomic nervous system has two subdivisions, the

postganglionic neurons, which run to the effector organ (cardiac muscle, smooth muscle, or a gland).

The first, the preganglionic neurons, arise in the CNS and run to a ganglion in the body.

It also differs from the sensory-somatic system is using two groups of motor neurons to stimulate the effectors instead of one. The actions of the autonomic nervous system are largely involuntary (in contrast to those of the sensory-somatic system). The contraction of both smooth muscle and cardiac muscle is controlled by motor neurons of the autonomic system. It is responsible for monitoring conditions in the internal environment and bringing about appropriate changes in them.

The autonomic nervous system consists of sensory neurons and motor neurons that run between the central nervous system (especially the hypothalamus and medulla oblongata) and various internal organs such as the: Link to a discussion of the mechanism by which the commands of the motor neurons of the sensory-somatic system are executed by skeletal muscles. Īll our conscious awareness of the external environment and all our motor activity to cope with it operate through the sensory-somatic division of the PNS. The Spinal NervesĪll of the spinal nerves are 'mixed' that is, they contain both sensory and motor neurons. *Note: These do contain a few sensory neurons that bring back signals from the muscle spindles in the muscles they control. (Contain 38% of all the axons connecting to the brain.) The peripheral nervous system is subdivided into the motor neurons running from the CNS to the muscles and glands - called effectors - that take action.sensory neurons running from stimulus receptors that inform the CNS of the stimuli.Link to discussion of the central nervous system. peripheral nervous system ( PNS) and the.

The effectors of the somatic nervous system are