Autonomic Nervous System (ANS) Overview

This set of flashcards summarizes key concepts about the Autonomic Nervous System (ANS), including its divisions, neuron structure, neurotransmitters, and regulatory control.

What are the two divisions of the Autonomic Nervous System (ANS)?

Sympathetic division and parasympathetic division.

What type of muscle does the somatic nervous system control?

Skeletal muscle.

What is the primary neurotransmitter used by the sympathetic division?

Norepinephrine (NE).

What is the primary neurotransmitter used by the parasympathetic division?

Acetylcholine (Ach).

What are the main effects of the sympathetic division?

Increases heart rate, shunts blood to skeletal muscles, dilates bronchial tubes, and inhibits digestive function.

What functions are associated with the parasympathetic division?

Digestion of food, excretion of waste, decreasing heart rate, and constriction of the bronchial tubes.

How does the ANS differ from the somatic nervous system in terms of neuron structure?

The ANS uses a 2-neuron chain (pre-ganglionic and post-ganglionic neurons) whereas the somatic nervous system uses a single motor neuron.

Where are the ganglia located in the sympathetic division?

Close to the spinal cord.

Where are the ganglia located in the parasympathetic division?

In or near the visceral effector organs.

What is the function of nicotinic receptors?

They are stimulatory and found on all postganglionic neurons.

What is the function of muscarinic receptors?

They can be either stimulatory or inhibitory, depending on the subclass.

What controls the Autonomic Nervous System?

The hypothalamus, brain stem, and spinal cord contribute to the control of the ANS.

What is the role of the hypothalamus in the ANS?

It is the main integration center for regulating heart activity, blood pressure, body temperature, and water balance.

What major functions does the brain stem regulate regarding the ANS?

It regulates heart rate, blood vessel diameter, pupil diameter, urination, and defecation.

What is the difference in the length of fibers between the sympathetic and parasympathetic divisions?

The parasympathetic division has long preganglionic and short postganglionic fibers, while the sympathetic division has short preganglionic and long postganglionic fibers.

What is a visceral reflex arc?

A reflex arc that includes a receptor, sensory neuron, integration center, motor neuron, and effector, such as pupil dilation or vomiting.