Overview of the Autonomic Nervous System

These flashcards cover key concepts related to the autonomic nervous system, including its divisions, key receptors, and the impact of various neurotransmitters and drugs.

Autonomic Nervous System (ANS)

Consists of motor neurons that innervate smooth muscle, cardiac muscle, and glands, operating via subconscious control.

Somatic Nervous System (SNS)

Innervates skeletal muscles and consists of single neuron pathways from CNS to effectors.

Neurotransmitters in ANS

Major neurotransmitters are acetylcholine (ACh) and norepinephrine (NE), with ACh primarily released by preganglionic neurons and NE by most sympathetic postganglionic neurons.

Parasympathetic Division

Promotes maintenance functions and conserves energy, often referred to as the 'rest and digest' system.

Sympathetic Division

Mobilizes the body during activity, often called the 'fight or flight' system, and prepares the body for stressful situations.

Dual Innervation

Refers to visceral organs being served by both the sympathetic and parasympathetic divisions, producing opposite effects.

Cholinergic Receptors

Receptors that respond to acetylcholine, including nicotinic and muscarinic types, each with specific effects based on their location.

Adrenergic Receptors

Two major classes (alpha and beta) that respond to norepinephrine and epinephrine, with effects depending on the subclass of receptor predominant on target organ.

Preganglionic Neuron

A neuron in the autonomic nervous system whose cell body is located in the CNS and has a myelinated axon, synapsing in a ganglion.

Postganglionic Neuron

A neuron that connects with the preganglionic neuron in an autonomic ganglion and extends to the effector organ.

Sympathetic Tone

Refers to a continual state of partial constriction of blood vessels, helping to control blood pressure.

Parasympathetic Tone

Refers to the dominant control of the parasympathetic division over heart rate and digestive activity, where organs are slightly activated.

Drugs that Influence ANS

Specific drugs can enhance or inhibit effects of neurotransmitters in the ANS, such as albuterol for asthma or propranolol for hypertension.