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Describe the preganglionic and postganglionic neurons in the autonomic system. Use a diagram to illustrate the difference in efferent outflow between somatic and autonomic nerves.
To review:
1. The preganglionic and postganglionic neurons in the autonomic system.
2. The difference in efferent outflow between somatic and autonomic nerves with the help of a diagram.
Introduction:
Autonomic nervous system is associated with the control of involuntary organs and tissues within the body. The activity of the cardiac muscle, glands as well as smooth muscles is regulated by the activity of the autonomic motor nerve. There is involvement of two neurons in the efferent pathway of the autonomic neurons.
Explanation of Solution
The efferent pathway for the conduction of nerve impulse in the autonomic system includes two nerve cells. The first neuron has its own cell body, which is present in the grey matter of the brain or the spinal cord. This neuron is referred to as the preganglionic neuron. The axon of the preganglionic neurons does not innervate with the associated organ but synapses with another autonomic neuron.
The preganglionic neuron synapses with the postganglionic neuron in order to complete the neural pathway. The axon of the postganglionic neuron synapses to the associated effector organ. There is a difference between the efferent outflow of the somatic and autonomic neurons. The somatic neurons synapse directly with their target organs whereas there is involvement of two neurons in the efferent outflow in the autonomic neurons. The difference between the efferent outflow of the somatic and autonomic neuron is shown below:
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Chapter 9 Solutions
Human Physiology
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Human Physiology: From Cells to Systems (MindTap ...BiologyISBN:9781285866932Author:Lauralee SherwoodPublisher:Cengage Learning