Comparison of Parasympathetic and Sympathetic Divisions

These flashcards cover key terms and concepts related to the parasympathetic and sympathetic divisions of the autonomic nervous system.

Parasympathetic Division

A division of the autonomic nervous system that promotes rest, digestion, and energy conservation.

Sympathetic Division

A division of the autonomic nervous system responsible for the fight or flight response. alerts adrenal glands

Rest and Digest

A state induced by the parasympathetic division characterized by decreased heart rate and increased digestive activity.

Fight or Flight

A state induced by the sympathetic division characterized by increased heart rate and energy mobilization.

Cranial Nerve X (Vagus Nerve) 10

A cranial nerve that decreases heart rate and is part of the parasympathetic division.

Acetylcholine

A neurotransmitter that is released by the parasympathetic nervous system at the neuromuscular junction.

Preganglionic Neuron

A neuron that originates in the CNS and extends to a ganglion.

Postganglionic Neuron

A neuron that extends from the ganglion to the target organ.

Urinary Function in Parasympathetic Activation

Increased urinary function due to stimulation from the parasympathetic division.

Increased Heart Rate

A physiological response primarily associated with sympathetic activation.

Sweating

A physiological response associated with sympathetic activation that helps cool the body.

Sympathetic Chain Ganglia

A series of ganglia located close to the spinal cord that process sympathetic nervous system signals.

Alertness Increase

A heightened state of awareness promoted by the sympathetic nervous system.

Decrease in GI Activity

A physiological response seen in sympathetic activation that reduces digestive processes.

Salivary Gland Secretion

Increased production of saliva facilitated by parasympathetic activation.

Cardiac Effectors

Organs affected by the autonomic nervous system that regulate heart rate.

Respiration Rate

A physiological parameter that is decreased during parasympathetic activation.

Adrenergic Neurons

Neurons that release norepinephrine in the sympathetic division.

Ganglion

A cluster of neuronal cell bodies located outside the CNS.

Short Preganglionic Fibers

Characteristics of the sympathetic nervous system pathways.

Long Postganglionic Fibers

Characteristics of sympathetic pathways which extend to target organs.

Energy Conservation

A key function of the parasympathetic division.

Stress Response

A physiological state induced by the sympathetic division during emergencies.

CNS Regions for Parasympathetic Output

Brainstem nuclei related to cranial nerves III, VII, IX, and X, as well as sacral spinal segments S2-S4.

Neurotransmitter Release

Mechanism by which the sympathetic nervous system increases innervation.

Skeletal Muscle Blood Flow

Increased during sympathetic activation for fight or flight responses.

Gastrointestinal (GI) Activity

Enhanced during rest and digest activities promoted by the parasympathetic division.

Vasoconstriction

Narrowing of blood vessels as part of the sympathetic response to stress.

Acetylcholine in PNS

The primary neurotransmitter that mediates actions of the parasympathetic nervous system.

What are the parasympathetic cranial nerves?

The parasympathetic cranial nerves include cranial nerves III (oculomotor), VII (facial), IX (glossopharyngeal), and X (vagus) which facilitate the parasympathetic nervous system.

What is the function of the oculomotor nerve (CN III) in the parasympathetic system?

The oculomotor nerve controls pupil constriction and lens shape for focusing.

What is the function of the facial nerve (CN VII) in the parasympathetic system?

The facial nerve regulates secretion of saliva, tears, and mucous.

What is the function of the glossopharyngeal nerve (CN IX) in the parasympathetic system?

The glossopharyngeal nerve stimulates saliva production in the parotid gland.

What is the function of the vagus nerve (CN X) in the parasympathetic system?

The vagus nerve innervates organs in the thorax and abdomen, slowing the heart rate and promoting digestion.

What are the main structures involved in the parasympathetic pathway?

The main structures include preganglionic neurons in the brainstem and sacral spinal cord, ganglia located near or within target organs, and postganglionic neurons that innervate the target tissues.

Where do the preganglionic neurons of the parasympathetic system originate?

The preganglionic neurons originate in the brainstem and the lateral gray matter of the sacral spinal cord (S2-S4).

What type of neurotransmitter is primarily used by preganglionic neurons of the parasympathetic pathway?

Preganglionic neurons primarily use acetylcholine (ACh) as their neurotransmitter.

What is the location of parasympathetic ganglia?

Parasympathetic ganglia are located near or within the walls of the target organs, unlike sympathetic ganglia which are located close to the spinal cord.

What are the primary structures involved in the sympathetic nervous system pathway?

The primary structures include preganglionic neurons located in the thoracolumbar region (T1-L2) of the spinal cord, sympathetic ganglia, and postganglionic neurons that innervate target organs.

Where do the preganglionic neurons of the sympathetic system originate?

The preganglionic neurons originate in the lateral horns of the spinal cord from the T1 to L2 segments.

What is the location of sympathetic ganglia?

Sympathetic ganglia are located in two main chains known as paravertebral ganglia (along the sides of the vertebral column) and prevertebral ganglia (near major abdominal arteries).

What type of neurotransmitter is primarily used by preganglionic neurons in the sympathetic pathway?

Preganglionic neurons primarily use acetylcholine (ACh) as their neurotransmitter.

What neurotransmitter do most postganglionic sympathetic neurons release?

Most postganglionic sympathetic neurons release norepinephrine (NE) as their neurotransmitter.