The somatic nervous system is under conscious control, while the ANS usually operates without conscious control.
From somatic senses and special senses
Somatic motor neurons directly synapse with effectors, while ANS motor pathways involve two neurons: a preganglionic neuron and a postganglionic neuron.
Sympathetic and Parasympathetic
Sympathetic
Parasympathetic
Skeletal muscles
Cardiac muscle, smooth muscle, and glands
A preganglionic neuron is the first neuron in an autonomic motor pathway that synapses with a postganglionic neuron in an autonomic ganglion.
In the thoracic and lumbar spinal cord
In certain cranial nerve nuclei and sacral spinal cord.
Sympathetic ganglia (sympathetic trunk and prevertebral ganglia) and parasympathetic ganglia (near or inside visceral effectors)
Cholinergic neurons release acetylcholine, which binds to cholinergic receptors
Adrenergic neurons release norepinephrine, which binds to adrenergic receptors like alpha and beta receptors
An agonist activates a receptor, mimicking natural effects, while an antagonist blocks a receptor, preventing those effects
It supports physical activity and rapid energy production (fight-or-flight response)
Sympathetic stimulation effects are longer lasting and more widespread than those of parasympathetic stimulation
An autonomic reflex adjusts the activities of smooth muscle, cardiac muscle, and glands, involving a reflex arc
The hypothalamus is the main control and integration center for the ANS, connected to both divisions
Near or within target organs
Interoreceptors
2 Neuron pathway;
- Preganglionic neuron synapses with postganglion neuron before reaching target oragn
Acetylcholine and norepinephrine
Fight or flight response, prepares body for emergency situations
Rest and digest response, promotes relaxation and recovery
Adrenal
Heart, smooth muscles, and glands
Vagus (X) nerve
Ciliary (eye), pterygopalatine (nasal/palate), submandibular (salivary glands), and otic (parotid glands)
Autonomic
Sweat glands, kidneys, and blood vessels
Active
Dilation of pupils
Increased heart rate
Wide airways
Increased blood flow
Digestion
Narrow pupils
SLUUD responses
Decreased heart rate
Adrenergic (release norepinephrine)
Cholinergic (release acetycholine ACh)
Throacolumbar outflow
Cranial Outflow
Myelinated
Unmyelinated
Alpha and beta receptors