2: Autonomic Nervous System Flashcards
How many synapses are used in the ANS?
two
Myelination of ANS
lightly myelinated or no myelination
What spinal segment does the sympathetic nervous system originate from?
thoracolumbar
Sympathetic preganglionic neurons
short
Where do sympathetic preganglionic neurons synapse?
sympathetic trunk (or ganglia in the abdomen or adrenal medulla)
Sympathetic postganglionic neurons
long
What spinal segment does the parasympathetic nervous system originate from?
craniosacral
Parasympathetic preganglionic neurons
long
Parasympathetic postganglionic neurons
short
What is the most important cranial nerve?
Vagus
Where do postganglionic axons of the vagus nerve travel to?
thoracic and abdominal viscera
Where do sacral postganglionic neurons travel to?
pelvic viscera
What do autonomic preganglionic neurons release onto target cells?
acetylcholine
What do parasympathetic postganglionic neurons release onto target cells?
acetylcholine
What do sympathetic postganglionic neurons release onto target cells?
norepinephrine
What do sympathetic postgalionic neurons release to sweat glands and blood vessels in skeletal muscle?
acetylcholine
What do postganglionic-like secretory cells of the adrenal medulla release into the bloodstream?
epinephrine and some noreprinephrine
Cholinergic
acetylcholine-releasing synapses
Adrenergic
norepinephrine and epinephrine-releasing synapses
2 types of cholinergic receptors
- nicotinic
- muscarinic
Nicotinic receptors
faster response, at autonomic ganglia and neuromuscular junction
Muscarinic receptors
slower response, at postganglionic parasympathetic and a few postganglionic sympathetic
