Flashcards in Autonomic Nervous System Deck (97)
The _____ nervous system is under conscious control and innervates skeletal muscle
The _____ nervous system is under involuntary control and innervates visceral organs
Each pathway in the autonomic nervous system consists of what 2 neurons?
preganglionic and postganglionic neurons
Where does the cell body of each preganglionic neuron reside?
In the CNS
Where do the axons of preganglionic neurons synapse with the bodies of postganglionic neurons?
In the autonomic ganglia located outside the CNS
All preganglionic neurons of the ANS release what NT?
All postganglionic neurons of the ANS release one of what 2 NTs?
ACh or norepinephrine
What are the 3 divisions of the ANS?
What NT do adrenergic receptors release?
What are receptors for norepinephrine on the effector organs called?
What NT do cholinergic receptors release?
What are receptors for ACh on the effector organs called?
What type of receptors describes some postganglionic parasympathetic neurons of the GI tract that release peptides or other substances as their NT rather than ACh?
Non-adrenergic, non-cholinergic receptors
Because all preganglionic neurons release ACh they are called what?
Most postganglionic parasympathetic neurons release ACh therefore they are called what?
Postganglionic sympathetic neurons release ACh and norepinephrine therefore they are called what?
cholinergic OR adrenergic
What is the junction between postganglionic neurons and their effector organs called?
the neuroeffector junction
Describe neuroeffector junctions
They are diffuse, branching networks in which the receptors are not concentrated in one region
What is the overall function of the sympathetic nervous system?
mobilize the body for activity
Where do the preganglionic neurons of the sympathetic division arise from?
In spinal cord segments T1 - L3 (thoracolumbar)
Where are the ganglia of the sympathetic nervous system found?
Near the spinal cord, either in the paravertebral ganglia (sympathetic chain) or in the prevertebral ganglia
Because sympathetic ganglia are located near the spinal cord, the preganglionic nerve axons are ____ and the postganglionic nerve axons are _____.
Preganglionic neurons of the sympathetic division are always _____ because they release ACh
Postganglionic neurons of the sympathetic division are _____ in all of the effector organs, except for the thermoregulatory sweat glands.
thermoregulatory sweat glands of the sympathetic division are innervated by what?
sympathetic cholinergic neurons, and therefore have muscarinic cholinorecpetors
What are the 4 types of adrenoreceptors of the sympathetic division?
Sympathetic adrenergic varicosities contain both the classic neurotransmitter and non-classic transmitters. What are they?
Non-classic: ATP and neuropeptide Y
Describe the roles of norepinephrine, ATP, and neuropeptide Y play in contraction via the sympathetic nervous system
1) ATP binds to purinergic receptors on the target tissue causing contraction of the vascular smooth tissue
2) Norepinephrine binds to its receptors on vascular smooth muscle and causes a second, more prolonged contraction
3) With more intense stimulation, the large dense-core vesicles release neuropeptide Y which binds to its receptors on the target tissue causing a third, slower phase of contraction
What is considered a specialized sympathetic ganglion whose preganglionic neurons originate in the thoracic spinal cord (T5-T9), pass through the sympathetic chain and the celiac ganglion without synapsing, and travel in the greater splanchnic nerve to the adrenal gland?
the adrenal medulla