Chapter 15: The Autonomic Nervous System

Cholinergic neurons release the neurotransmitter: (Cholinergic receptors include nicotinic receptors and muscarinic receptors)

acetylcholine

In general, the sympathetic and parasympathetic divisions of the autonomic nervous system are to each other.

antagonistic

Sensory neurons are located in organs, blood vessels, muscles, and the nervous system. Motor neurons innervate smooth muscle, cardiac muscle, and glands:

autonomic nervous system

- Functions such as heart rate and force of ventricular contraction, blood pressure and blood vessel diameter are controlled by autonomic reflexes that occur when nerve impulses pass through an: - The reflex arc is composed of a

autonomic reflex arc receptor, a sensory neuron, an integrating center, motor neurons and an effector

The abdomen and pelvis also contain major autonomic plexuses which are often named after the artery along which they are distributed. These include the:

celiac (solar) plexus, the superior mesenteric plexus, the inferior mesenteric plexus, the renal plexus and the hypogastric plexus

Based on the neurotransmitter they produce and release, autonomic neurons are considered as either:

cholinergic or adrenergic

Adrenergic neurons release:

norepinephrine (noradrenalin)

In the ____________________________ division, cell bodies of the _____________________ neurons are in the nuclei of four cranial nerves (III, VII, IX and X) in the brain stem and in the lateral gray matter of sacral segments 2-4 of the spinal cord.

parasympathetic, preganglionic

Most autonomic motor pathways consist of two motor neurons in series:

preganglionic neuron postganglionic neuron

There are two types of autonomic ganglia:

sympathetic and parasympathetic (Sympathetic ganglia are sites of synapses between sympathetic preganglionic and postganglionic neurons.)

After axons of sympathetic preganglionic neurons enter sympathetic trunk ganglia, they may connect with postganglionic neurons in one of 4 ways:

1) An axon may synapse with postganglionic neurons in the first ganglion it reaches. 2) An axon may ascend or descend to a higher or lower ganglion before synapsing with postganglionic neurons. 3) An axon may continue, without synapsing, through the sympathetic trunk ganglion to end at a prevertebral ganglion and synapse with postganglionic neurons. 4) An axon may also pass, without synapsing, through the sympathetic trunk ganglion and a prevertebral ganglion and then extend to the adrenal medullae.

There are 2 major types of sympathetic ganglia:

Sympathetic trunk ganglia (lie in a vertical row on either side of the vertebral column) and prevertebral ganglia (lie anterior to the vertebral column and close to the large abdominal arteries).

Cell bodies of the sympathetic preganglionic neurons are part of the lateral gray horns of all thoracic segments and of the first two lumbar segments of the spinal cord. T/F

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The axon of a single, myelinated somatic motor neuron extends from the central nervous system to the skeletal muscle fiber it innervates. T/F

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The nervous system is associated with virtually all functions of the body. It is intimately involved in maintaining homeostasis throughout the body. T/F

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The paired sympathetic trunk ganglia are anterior and lateral to the vertebral column. Usually, there are 2 cervical, 11 or 12 thoracic, 4 or 5 lumbar, 4 or 5 sacral sympathetic trunk ganglia and 1 coccygeal ganglion. T/F

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Each division of the autonomic nervous system has two motor neurons:

The preganglionic (cell body in the brain or spinal cord) and the postganglionic (cell body and dendrites located in an autonomic ganglion where it synapses with preganglionic axons).

The autonomic nervous system is divided into two divisions:

The sympathetic nervous system is often referred to as the fight-or-flight division because its stimulation leads to increased alertness and metabolism to be ready for an emergency. The parasympathetic nervous system is referred to as the rest-and-digest division as its stimulation slows down most body activity.

Sensory neurons are related to touch, pain, temperature, proprioception, sight, hearing, taste, smell, and equilibrium. Motor neurons innervate skeletal muscles:

somatic nervous system

In the _____________________ division, the cell bodies of ________________________ neurons are in the lateral horns of the gray matter in the 12 thoracic and first 2 or 3 lumbar segments of the spinal cord.

sympathetic, preganglionic