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 PHYSICOLOGY
- Describe the general rules for neurotransmitters secreted by pre-and postganglionic neurons in the autonomic division of the nervous system. Be sure to identify them and specify the types of receptors each binds toarrow_forwardDescribe the structure of the neuroeffector junction at which postganglionic autonomic neurons innervate their target organsarrow_forwardIn the sympathetic division of the autonomic nervous system: Select one: The ratio between the number of postganglionic and preganglionic neurons is small. A single preganglionic neuron usually synapses with a single postganglionic neuron. An important functional characteristic is convergence of the preganglionic fibers. Preganglionic fibers are usually much longer than the postganglionic fibers. Activity of the neurons tends to have a more generalized and widespread effect on the body.arrow_forward
- compare and contrast the differences between the sympathetic and parasympathetic nervous systems. Use the following scenarios: Scenario 1: You are walking outside late at night and you hear something in the bushes as you approach your home. Which system will dominate and what physiological changes will occur? Scenario 2: You have just finished a big dinner and now you are relaxing in your recliner to watch the big ball game. Which system will dominate and what physiological changes will occur? Be sure to at least include what happens to heart rate, blood pressure, and digestion. You may include other physiological variables as well. "Not a homework assignment"arrow_forwardContrast the functions of the sympathetic and para-sympathetic divisions of the autonomic nervous system.arrow_forwardDefine sympathetic chain ganglionarrow_forward
- Sympathetic and parasympathetic preganglionic fibers release the neurotransmitter:arrow_forwardCompare the sympathetic nervous system to the parasympathetic nervous system and the endocrine system. Explain each system and give an original example of each.arrow_forwardIn most instances the sympathetic and parasympathetic have opposite effects on effectors where they both innervate. Describe an example where they have cooperative effects, not the opposite.arrow_forward
- Sketch a diagram or a flow chart to explain how does the autonomic nervous system exert its effects on its target tissue and organs. Give a specific example to illustrate your response.arrow_forwardDescribe how depolarisation of a preganglionic parasympathetic neuron leads to the autonomic regulation of an effector organ (e.g. sinoatrial node).arrow_forwardDiscuss the embryological origins of the ganglia in detail. What effect do these have on the nervous system's and the body's functioning?arrow_forward
- Human Physiology: From Cells to Systems (MindTap ...BiologyISBN:9781285866932Author:Lauralee SherwoodPublisher:Cengage Learning