Autonomic Nervous System Overview and Functions

Sympathetic Division

Regulates fight-or-flight responses in the body.

Parasympathetic Division

Conserves and restores body energy post-activity.

Autonomic Reflex

Adjusts activities of smooth muscle and glands.

Autonomic Reflex Arc

Pathway involving receptor, sensory neuron, and effector.

Hypothalamus

Major control center for autonomic nervous system.

Dual Innervation

Organs receive input from both ANS divisions.

Preganglionic Neurons

First motor neurons in autonomic pathways.

Postganglionic Neurons

Second motor neurons in autonomic pathways.

Celiac Plexus

Largest autonomic plexus in the body.

Pelvic Splanchnic Nerves

Branch from sacral spinal nerves, innervate pelvic organs.

Adrenergic Neurons

Most sympathetic postganglionic neurons, release norepinephrine.

Muscarinic Receptors

Found in effectors of parasympathetic postganglionic neurons.

Cholinergic Neurons

Sympathetic postganglionic neurons in sweat glands.

Somatic Nervous System

Operates under conscious control, affects skeletal muscles.

Autonomic Nervous System

Functions without conscious control, affects internal organs.

Interoceptors

Sensory receptors for internal body conditions.

Enteric Plexuses

Nerves and ganglia in the digestive canal.

Sympathetic Trunk Ganglia

Contain sympathetic postganglionic neurons near spinal cord.

Visceral Effectors

Targets of autonomic motor neurons, include organs.

Excitation and Inhibition

Opposing effects of sympathetic and parasympathetic divisions.

Long Preganglionic Axons

Characteristic of parasympathetic neurons, near visceral organs.

Short Preganglionic Axons

Characteristic of sympathetic neurons, near spinal cord.

Autonomic Ganglion

Synapse point between preganglionic and postganglionic neurons.

Preganglionic neuron

First motor neuron in autonomic pathways.

Postganglionic neuron

Second motor neuron in autonomic pathways.

Sympathetic ganglia

Ganglia associated with the sympathetic nervous system.

Parasympathetic ganglia

Ganglia located near or within visceral effectors.

Cholinergic neurons

Neurons that release acetylcholine in the ANS.

Adrenergic neurons

Neurons that release norepinephrine in the ANS.

Nicotinic receptors

Cholinergic receptors on postganglionic neurons.

Muscarinic receptors

Cholinergic receptors on parasympathetic effectors.

Alpha receptors

Type of adrenergic receptor responding to norepinephrine.

Beta receptors

Type of adrenergic receptor responding to epinephrine.

Agonist

Substance activating a receptor, mimicking neurotransmitter effects.

Antagonist

Substance blocking a receptor, preventing neurotransmitter effects.

Sympathetic division

Nervous system division for fight-or-flight responses.

Parasympathetic division

Nervous system division for rest-and-digest activities.

Autonomic reflex

Reflex adjusting smooth muscle, cardiac muscle, and glands.

Autonomic reflex arc

Pathway including receptor, sensory neuron, and effectors.

Epinephrine

Hormone released by adrenal medulla, acting on adrenergic receptors.

Norepinephrine

Neurotransmitter released by most sympathetic postganglionic neurons.

Sympathetic trunk ganglia

Ganglia located alongside the vertebral column.

Prevertebral ganglia

Ganglia located anterior to the vertebral column.

Visceral effectors

Organs innervated by autonomic nervous system.

Fight-or-flight response

Physiological reaction to perceived harmful events.

Dual innervation

Organ receives nerves from both ANS divisions.

Sympathetic division

Prepares body for stress responses.

Parasympathetic division

Promotes rest and digest functions.

Vagotomy

Surgical cutting of the vagus nerve.

Megacolon

Abnormally large colon due to nerve issues.

Reflex sympathetic dystrophy

Pain syndrome from sympathetic nervous activation.

Sympathetic trunk ganglia

Contain sympathetic postganglionic neurons.

Autonomic ganglion

Synapse point for preganglionic and postganglionic neurons.

Enteric plexuses

Nerves and ganglia in digestive canal walls.

Somatic nervous system

Operates under conscious control.

Autonomic nervous system

Functions without conscious control.

Cardiac muscle

Involuntary muscle controlled by ANS.

Smooth muscle

Muscle type influenced by autonomic signals.

Glands

Tissues that secrete substances, regulated by ANS.

Sympathetic preganglionic axons

Short axons that synapse near spinal cord.

Parasympathetic preganglionic axons

Long axons that synapse in organ walls.

Motor pathways

Two neurons in series for autonomic control.

Hypersensitivity

Increased sensitivity to stimuli, often in pain.

Baclofen

Drug used to reduce pain in RSD.

Parasympathetic ganglia

Ganglia associated with the parasympathetic nervous system.

Dysautonomia

Disorder causing autonomic nervous system dysfunction.

Orthostatic hypotension

Dizziness upon standing due to blood pressure drop.

Autonomic nerve neuropathy

Neuropathy affecting autonomic nerves, causing dysfunction.

Biofeedback

Technique to control autonomic responses using feedback.

Hyperhidrosis

Excessive sweating due to overactive sweat glands.

Mass reflex

Exaggerated reflex response after severe spinal injury.

Megacolon

Abnormally large colon due to nerve development issues.

Congenital megacolon

Birth defect causing colon dilation and constipation.

Reflex sympathetic dystrophy

Pain syndrome with hypersensitivity and sweating.

Lateral gray horns

Spinal cord regions housing sympathetic preganglionic neurons.

Cranial nerve nuclei

Brainstem nuclei for parasympathetic preganglionic neurons.

Visceral effectors

Organs affected by parasympathetic ganglia.

Diabetic neuropathy

Nerve damage due to long-term diabetes.

Signs of dysautonomia

Symptoms include dizziness, digestive, and urinary issues.

Treatment for dysautonomia

Focus on underlying disease and symptom management.

Spinal cord injury

Damage to the spinal cord affecting autonomic function.

Autonomic dysfunction

Impaired autonomic nervous system function affecting homeostasis.