M15: Autonomic Nervous System

What are the two main branches of the Autonomic Nervous System?

Parasympathetic and Sympathetic branches

What is the primary function of the Parasympathetic Nervous System?

Rest and Digest

What is the primary function of the Sympathetic Nervous System?

Fight or Flight

What type of fibers are associated with the Parasympathetic Nervous System?

Pre-ganglionic fibers are long and myelinated; post-ganglionic fibers are short and unmyelinated.

Where do the pre-ganglionic fibers of the Sympathetic Nervous System originate?

Thoracic and lumbar segments of the spinal cord

What neurotransmitter is primarily used by the Parasympathetic Nervous System?

Acetylcholine

What neurotransmitters are primarily used by the Sympathetic Nervous System?

Epinephrine and Norepinephrine

What are the two types of receptors associated with the Autonomic Nervous System?

Cholinergic and Adrenergic receptors

What is the role of Muscarinic receptors in the Parasympathetic Nervous System?

They mediate various effects, including slowing heart rate (e.g., M2 receptor).

What is the function of the ɑ1 adrenergic receptor?

Smooth muscle contraction and vasoconstriction

What is the function of the β1 adrenergic receptor?

Increases heart rate and force of contraction, stimulates salivary gland amylase secretion.

What are the stereotypic responses of the Sympathetic division during a fight-or-flight response?

Increased heart rate, blood pressure, vasoconstriction in most blood vessels, and mobilization of energy sources.

What are the stereotypic responses of the Parasympathetic division?

Increased saliva production, digestion stimulation, and control of nausea and vomiting.

What is Raynaud's Syndrome?

A condition caused by hyperactivation of the sympathetic nervous system leading to extreme vasoconstriction in peripheral blood vessels.

What are the symptoms of Raynaud's Syndrome?

Affected parts turn white and blue, accompanied by numbness and pain.

How do somatic reflexes differ from autonomic reflexes?

Somatic reflexes involve voluntary control and skeletal muscles, while autonomic reflexes control involuntary functions.

What is the pathway for an autonomic reflex?

Visceral sensory receptors send signals to the CNS, which then sends efferent information to preganglionic neurons that synapse onto postganglionic neurons.

What is the role of adrenergic receptors in the sympathetic nervous system?

They mediate responses such as vasodilation in skeletal muscle and bronchodilation.

What is the significance of the sympathetic chain ganglia?

They serve as synapse points for pre-ganglionic fibers of the sympathetic nervous system.

What is the difference between ionotropic and metabotropic receptors?

Ionotropic receptors are ligand-gated ion channels, while metabotropic receptors are G-protein coupled receptors.

What physiological functions are regulated by the autonomic nervous system?

Heart rate, digestion, respiratory rate, pupillary response, urination, and sexual arousal.

What is the effect of sympathetic stimulation on digestion?

It inhibits digestion.

What is the effect of parasympathetic stimulation on heart rate?

It slows the heart rate.