Cardio-Inhibitory
Centre (CIC)
- Dorsal motor nucleus of vagus
nerve in Medulla Oblongata
- On stimulation causes slowing of
the heart rate
Parasympathetic Nerve Supply
- Nerve fibres from the CIC travel
through the vagus nerve to the Heart (mainly to
the atria, SA node and AV node).
- Ventricles escape from effects of
strong prolonged vagal stimulation - this is
called the vagal escape
Vasoconstrictor centre (VCC)
- No separate cardioaccelerator
centre but the VCC produces both vasoconstriction
and tachycardia
Sympathetic Nerve Supply
- From the VCC, fibres descend down
in the spinal cord to the lateral horn cells
- Preganglionic sympathetic fibres
from the upper 5 thoracic segments ascend in the
sympathetic chain to the superior, middle and
inferior cervical ganglia.
- Post ganglionic nerve fibres
descend to the heart (to all parts of the heart
muscle)
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