The Autonomic Nervous System

These flashcards cover the key concepts, functions, and anatomical features of the Autonomic Nervous System (ANS), comparing its sympathetic and parasympathetic divisions.

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

The two main divisions are the sympathetic division and the parasympathetic division.

What is the primary function of the sympathetic division?

The sympathetic division mobilizes body systems during emergency situations, often referred to as the 'fight-or-flight' response.

What does the parasympathetic division do?

The parasympathetic division conserves energy and promotes non-emergency functions, often referred to as the 'resting and digesting' system.

What is the role of the hypothalamus in the ANS?

The hypothalamus oversees all ANS activities and regulates homeostasis by influencing the autonomic nervous system and managing hormones.

How are the lengths of preganglionic and postganglionic fibers different in sympathetic and parasympathetic divisions?

In the sympathetic division, the preganglionic fibers are short and postganglionic fibers are long. In the parasympathetic division, the preganglionic fibers are long and postganglionic fibers are short.

What neurotransmitters are released by preganglionic and postganglionic neurons in the sympathetic division?

Preganglionic neurons release acetylcholine (ACh), while postganglionic neurons release norepinephrine (NE).

What neurotransmitter is primarily released in the parasympathetic division?

Acetylcholine (ACh) is the primary neurotransmitter released by both preganglionic and postganglionic neurons in the parasympathetic division.

Describe the role of the vagus nerve in the parasympathetic division.

The vagus nerve accounts for 75% of all parasympathetic fibers, influencing heart rate, gastrointestinal activity, and other functions.

What is the anatomical origin of the sympathetic nervous system?

The sympathetic nervous system originates from the thoracolumbar region, specifically spinal segments T1 to L2.

What is the anatomical origin of the parasympathetic nervous system?

The parasympathetic nervous system originates from the brain stem and sacral spinal cord (S2 to S4).