Chapter 11 Efferent Division: Autonomic and Somatic Motor Control

What are the two main divisions of the autonomic nervous system?

The sympathetic branch and the parasympathetic branch.

What type of muscles do autonomic neurons control?

Smooth muscle, cardiac muscle, many glands, lymphoid tissue, and some adipose tissue.

Where do most sympathetic pathways originate in the spinal cord?

In the thoracic and lumbar regions.

What are the primary autonomic neurotransmitters?

Acetylcholine and norepinephrine.

What is the neuroeffector junction?

The synapse between an autonomic neuron and its target cells.

What type of receptors do postganglionic sympathetic neurons secrete norepinephrine onto?

Adrenergic receptors.

What do cholinergic muscarinic receptors respond to?

Acetylcholine.

What is the function of acetylcholinesterase in the synapse?

It breaks down acetylcholine.

What is the role of the hypothalamus in the autonomic division?

It controls the autonomic division along with the pons and medulla.

What is the difference in the location of parasympathetic ganglia compared to sympathetic ganglia?

Parasympathetic ganglia are located on or near their target organs while sympathetic ganglia lie close to the spinal cord or along the descending aorta.

What type of receptors respond most strongly to norepinephrine among adrenergic receptors?

Alpha receptors.

How does the somatic motor pathway differ from the autonomic pathways?

Somatic motor pathways have a single neuron that directly controls skeletal muscle, whereas autonomic pathways consist of preganglionic and postganglionic neurons.

What is the synapse called where a somatic motor neuron terminates on a muscle fiber?

The neuromuscular junction.

What is the effect of acetylcholine binding to nicotinic receptors at the muscle fiber?

It opens cation channels, causing depolarization of the muscle fiber.

What role does the adrenal medulla play in the autonomic nervous system?

It secretes epinephrine and is controlled by sympathetic preganglionic neurons.

What type of control does the maintenance of homeostasis within the body rely on?

A balance of autonomic control, endocrine control, and behavioral responses.