Autonomic Nervous System Flashcards
What are the 2 main divisions of the nervous system?
Central nervous system
Peripheral nervous system
What are the 2 main divisions of the peripheral nervous system?
Afferent (sensory) nerves
Efferent (motor) nerves
What are the 2 divisions of the efferent (motor) nervous system?
Somatic (voluntary) nervous system
Autonomic (involuntary) nervous system
What are the 2 divisions of the autonomic (involuntary) nervous system?
Parasympathetic nervous system
Sympathetic nervous system
What areas of the spinal column do sympathetic nerves emerge from?
Throracolumbar outflow
For sympathetic nerves, how does the length of preganglionic and postganglionic fibres compare?
Short preganglionic and long postganglionic fibres
Where are sympathetic ganglia located?
Prevertebral ganglia
Paravertebral ganglia
In the sympathetic nervous system, the synapses between pre and post-ganglionic cells are what?
Cholinergic and nicotinic
In the parasympathetic nervous system, the synapses between pre and post-ganglionic cells are what?
Cholinergic and nicotinic
In the parasympathetic nervous system, the fibres between post-ganglionic cells and targets are what?
Cholinergic and muscarinic
What do post-ganglionic cells in the adrenal medulla release?
Adrenaline
What do post-ganglionic fibres in the adrenal medullar contribute to?
Mass activation, being part of the sympathetic nervous system and releasing adrenaline
What receptors do adrenaline and noradrenaline act on?
Adrenergic receptors
Alpha receptors
Beta receptors
What kinds of receptors does acetycholine act on?
Nicotinic and muscarinic receptors
In the eye, what does sympathetic activation cause?
Contraction of the radial muscle of the iris (pupil dilates)
Relaxation of the ciliary muscle surrounding the lens (eye focuses further away)
What do eye drops used to dilate the pupil often contain?
Muscarinic antagonist
Alpha 1 agonist
What does the parasympathetic system cause in the heart?
Release of acetylcholine
Decrease in heart rate
In blood vessels, what does the sympathetic system cause?
Vasocontriction, but causes vasodilation in some that express B2 receptors
In the lung, what does activation of the sympathetic nervous system cause?
Relaxation of smooth muscle
What are some clinical applications of understanding the receptors within the ANS?
Side effects and contraindications of drugs affecting ANS should be predictable
Autonomic neuropathy may be the cause of syncope, bladder problems, bowel problems etc
Diagnosis and progress of disease can be monitored by tests of autonomic function, such as cardiovascular response to deep breathing, Valsalva manoeuvre and tilt test
