Autonomic nervous system Flashcards
Which component of the nervous system is the autonomic system a part of?
Visceral efferent
Function of the autonomic nervous system
Controls involuntary activities of smooth muscle (e.g. vasoconstriction/dilation), cardiac muscle, glands (salivary, GI, sweat), and metabolism.
2 divisions of the autonomic nervous system
Sympathetic and parasympathetic nervous system
Where in the CNS are the cell bodies of preganglionic parasympathetic neurons located?
Brainstem and sacral spinal cord (S 2-4)
Which parasympathetic preganglionic neurons have their cell bodies in the brainstem?
Oculomotor (CN III), Facial (CN VII), Glossopharyngeal (CN IX) nerves that control head structures, and the Vagus nerve (CN X) that controls thoracic and abdominal viscera.
Which parasympathetic pre-ganglionic neurons have their cell bodies in the spinal cord?
S 2, 3, 4 which control the pelvic organs
Where are the cell bodies of sympathetic pre-ganglionic neurons found?
Thoracic and lumbar regions of the spinal cord (T1-L2)
Which division of the ANS is the adrenal medulla a part of?
Sympathetic NS
What is a ganglion?
A collection of neuron cell bodies in the PNS where the preganglionic nerve synapses with the postganglionic nerve.
Difference of ganglion location in parasympathetic and sympathetic NS
In the parasympathetic NS, the ganglion is closer to / in the target/effector.
Structure of the ANS
The preganglionic neuron has its cell body in the CNS and synapses with the postganglionic neuron (or adrenal medulla) at the ganglion in the PNS. The impulse then travels to the effector/target.
How is the ANS structured when the adrenal medulla is involved?
The sympathetic neuron has its cell body in the CNS and travels to the adrenal medulla, triggering the release of a hormone which is transported in the blood to the effector/target.
Comparison of preganglionic and postganglionic neuron lengths in the parasympathetic NS
Preganglionic neuron is longer than the postganglionic neuron (because the ganglion is close to / in effector organ)
Comparison of preganglionic and postganglionic neuron length in sympathetic NS
Both similar in length
Where do sympathetic pre and postganglionic neurons synapse?
In the sympathetic chain or in one of the collateral ganglia or adrenal medulla
Which 2 neurons is the ANS composed of?
Preganglionic and postganglionic neurons
Effector organs innervated by the ANS
Smooth muscle, cardiac muscle, glands
2 groups of ganglia
Sensory ganglia (transmit info from periphery to CNS) and autonomic ganglia (transmit info from CNS to periphery)
Function of parasympathetic NS
Acts on single organs in the body core (e.g. salivary glands, heart, iris and ciliary muscles, bronchi, GIT…). Conserves energy and has anabolic effects such as storing energy (digestion), reducing heart rate.
Which nerves are part of the parasympathetic NS?
Oculomotor (CN III), Facial (CN VII), Glossopharyngeal (CN IX), Vagus (CN X), and sacral nerves S2-4.