ANAT 101
Autonomic Nervous System
Q&A
2024
1. Describe the preganglionic and postganglionic neurons of the autonomic nervous system.
• Preganglionic neuron: cell body in CNS, synapses on autonomic ganglion in PNS
o Myelinated
o Thoracic and lumbar region in sympathetic
o Cervical and sacral region in parasympathetic
• Postganglionic neuron: cell body in autonomic ganglion, synapses on effector
o Unmyelinated
2. Where are the soma (cell bodies) of the preganglionic sympathetic neurons located? How about
the parasympathetic cell bodies? Where along the spinal cord are they located for both
divisions?
,3. Where do you find the cell bodies of the post-ganglionic neurons?
4. What are the two types of neurons in the ANS?
• Cholinergic: release ACh
o All sympathetic & parasympathetic preganglionic neurons
o Few sympathetic postganglionic neurons - mostly sweat glands
o All parasympathetic postganglionic neurons
• Adrenergic: release norepinephrine (NE)
5. Be able to describe the neurotransmitters and receptors involved in autonomic responses.
• Cholinergic: release ACh
• Adrenergic: release norepinephrine (NE)
6. What are the 2 types of Cholinergic receptors?
• Nicotinic receptors: in plasma membrane of dendrites and cell bodies of sympathetic
and parasympathetic postganglionic neurons, chromaffin cells of adrenal medullae, and
motor end plate at neuromuscular junction
o Causes depolarization and sometimes hyperpolarization
• Muscarinic receptors: in plasma membrane of all effectors of parasympathetic
postganglionic axons, sweat glands
o Contraction of iris of eye
o Relaxes smooth muscles in GI tract
7. What are the 2 kinds of adrenergic receptors?
• Alpha / a receptors: NE stimulates alpha more than beta and is really stimulated by
epinephrine
o a1: generally excites effectors - Iris of eye (dilates pupil) and also found in blood
vessels of smooth muscle fibers of skin, salivary glands, abdominal viscera
(causes vasoconstriction) -When you stimulate fight or flight, you'll decrease
blood flow here
o a2: generally inhibits effectors - Pancreas (decrease insulin secretion)
• Beta: /β receptors: is really stimulated by epinephrine
o β1: generally excites effectors - in the SA node of heart (beats faster) and
contractile muscles (beat harder) and also in kidneys (produces renin) and also
found in blood vessels of heart and skeletal muscles (increases blood flow to
skeletal muscles) - When you stimulate fight or flight, you'll increase blood flow
here
o β2: generally inhibits effectors - airways, heart blood vessels, skeletal muscle,
adipose tissue, bladder, eye, liver
, o β3: are only in brown adipose tissue in babies and hibernating animals for
thermogenesis (heat production)
8. Where exactly are nicotinic receptors expressed? Where are the muscarinic receptors
expressed?
• Nicotinic receptors are expressed in plasma membrane of dendrites and cell bodies of
sympathetic and parasympathetic postganglionic neurons, chromaffin cells, and motor
plate at neuromuscular junctions
• Muscarinic receptors are expressed in plasma membrane of all parasympathetic
postganglionic axons, sweat glands
9. Which sympathetic pathway neurons are myelinated? How about non-myelinated?
• Sympathetic pathway neurons have preganglionic neurons myelinated and
postganglionic neurons unmyelinated
• Parasympathetic pathway neurons have preganglionic neurons myelinated and
postganglionic neurons unmyelinated
10. What neurotransmitter is released by the sympathetic & parasympathetic preganglionic
neurons? What are their target structures? Where are they located? What receptor type do
they express?
• Sympathetic preganglionic: ACh through autonomic ganglion to postganglionic neuron
o Postganglionic neuron: NE to glands, cardiac muscle, smooth muscle
• Sympathetic preganglionic: ACh through adrenal medulla which releases epinephrine
and NE to blood vessels
• Parasympathetic preganglionic: Ach through autonomic ganglion to postganglionic
neuron
o Postganglionic neuron: ACh to glands, cardiac muscle, smooth muscle
11. What neurotransmitter is released by the post ganglionic sympathetic neurons? What are the
sympathetic effectors/target structures? Which tissues have only sympathetic innervation?
• Postganglionic neurons in:
o Sympathetic:
▪ Preganglionic synapses on autonomic ganglion, postganglionic releases
NE
▪ Preganglionic synapses on adrenal medulla, postganglionic releases
epinephrine & NE
o Parasympathetic synapses on autonomic ganglion, postganglionic releases ACh
12. What endogenous transmitter stimulates the nicotinic receptors? Muscarinic? Adrenergic
receptors?
• Endogenous = naturally occurring in the body
Autonomic Nervous System
Q&A
2024
1. Describe the preganglionic and postganglionic neurons of the autonomic nervous system.
• Preganglionic neuron: cell body in CNS, synapses on autonomic ganglion in PNS
o Myelinated
o Thoracic and lumbar region in sympathetic
o Cervical and sacral region in parasympathetic
• Postganglionic neuron: cell body in autonomic ganglion, synapses on effector
o Unmyelinated
2. Where are the soma (cell bodies) of the preganglionic sympathetic neurons located? How about
the parasympathetic cell bodies? Where along the spinal cord are they located for both
divisions?
,3. Where do you find the cell bodies of the post-ganglionic neurons?
4. What are the two types of neurons in the ANS?
• Cholinergic: release ACh
o All sympathetic & parasympathetic preganglionic neurons
o Few sympathetic postganglionic neurons - mostly sweat glands
o All parasympathetic postganglionic neurons
• Adrenergic: release norepinephrine (NE)
5. Be able to describe the neurotransmitters and receptors involved in autonomic responses.
• Cholinergic: release ACh
• Adrenergic: release norepinephrine (NE)
6. What are the 2 types of Cholinergic receptors?
• Nicotinic receptors: in plasma membrane of dendrites and cell bodies of sympathetic
and parasympathetic postganglionic neurons, chromaffin cells of adrenal medullae, and
motor end plate at neuromuscular junction
o Causes depolarization and sometimes hyperpolarization
• Muscarinic receptors: in plasma membrane of all effectors of parasympathetic
postganglionic axons, sweat glands
o Contraction of iris of eye
o Relaxes smooth muscles in GI tract
7. What are the 2 kinds of adrenergic receptors?
• Alpha / a receptors: NE stimulates alpha more than beta and is really stimulated by
epinephrine
o a1: generally excites effectors - Iris of eye (dilates pupil) and also found in blood
vessels of smooth muscle fibers of skin, salivary glands, abdominal viscera
(causes vasoconstriction) -When you stimulate fight or flight, you'll decrease
blood flow here
o a2: generally inhibits effectors - Pancreas (decrease insulin secretion)
• Beta: /β receptors: is really stimulated by epinephrine
o β1: generally excites effectors - in the SA node of heart (beats faster) and
contractile muscles (beat harder) and also in kidneys (produces renin) and also
found in blood vessels of heart and skeletal muscles (increases blood flow to
skeletal muscles) - When you stimulate fight or flight, you'll increase blood flow
here
o β2: generally inhibits effectors - airways, heart blood vessels, skeletal muscle,
adipose tissue, bladder, eye, liver
, o β3: are only in brown adipose tissue in babies and hibernating animals for
thermogenesis (heat production)
8. Where exactly are nicotinic receptors expressed? Where are the muscarinic receptors
expressed?
• Nicotinic receptors are expressed in plasma membrane of dendrites and cell bodies of
sympathetic and parasympathetic postganglionic neurons, chromaffin cells, and motor
plate at neuromuscular junctions
• Muscarinic receptors are expressed in plasma membrane of all parasympathetic
postganglionic axons, sweat glands
9. Which sympathetic pathway neurons are myelinated? How about non-myelinated?
• Sympathetic pathway neurons have preganglionic neurons myelinated and
postganglionic neurons unmyelinated
• Parasympathetic pathway neurons have preganglionic neurons myelinated and
postganglionic neurons unmyelinated
10. What neurotransmitter is released by the sympathetic & parasympathetic preganglionic
neurons? What are their target structures? Where are they located? What receptor type do
they express?
• Sympathetic preganglionic: ACh through autonomic ganglion to postganglionic neuron
o Postganglionic neuron: NE to glands, cardiac muscle, smooth muscle
• Sympathetic preganglionic: ACh through adrenal medulla which releases epinephrine
and NE to blood vessels
• Parasympathetic preganglionic: Ach through autonomic ganglion to postganglionic
neuron
o Postganglionic neuron: ACh to glands, cardiac muscle, smooth muscle
11. What neurotransmitter is released by the post ganglionic sympathetic neurons? What are the
sympathetic effectors/target structures? Which tissues have only sympathetic innervation?
• Postganglionic neurons in:
o Sympathetic:
▪ Preganglionic synapses on autonomic ganglion, postganglionic releases
NE
▪ Preganglionic synapses on adrenal medulla, postganglionic releases
epinephrine & NE
o Parasympathetic synapses on autonomic ganglion, postganglionic releases ACh
12. What endogenous transmitter stimulates the nicotinic receptors? Muscarinic? Adrenergic
receptors?
• Endogenous = naturally occurring in the body
