Vagal tone
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Vagal tone is activity of the vagus nerve and a fundamental component of the parasympathetic branch of the autonomic nervous system. This branch of the nervous system is not under conscious control an
Heart rate (HR) (first row), tidal volume (Vt) (second row), Vt and superimposed HR (third row). The HR modulation is clearly visible: HR increases with inspiration and decreases with expiration.
Cranial nerves
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Cranial nerves are nerves that emerge directly from the brain, including the brainstem, in contrast to spinal nerves, which emerge from segments of the spinal cord. They relay information between the
Vagal tone
…Vagal tone is activity of the vagus nerve (the 10th cranial nerve) and a fundamental component of the parasympathetic branch of the autonomic nervous system. This branch of the nervous system is not under conscious…
View of the human brain from below showing the cranial nerves on an autopsy specimen
The facial nerve (VII) supplies the muscles of facial expression. Damage to the nerve causes a lack of muscle tone on the affected side, as can be seen on the right side of the face here.
The hypoglossal nerve (XII) supplies the muscles of the tongue. A damaged hypoglossal nerve will result in an inability to stick the tongue out straight; here seen in an injury resulting from branchial cyst surgery.