Anatomy of the heart lecture 2 - nerve innervation Flashcards
What is the autonomic nervous supply to the heart
cardiac plexuses - sits behind the heart
- sympathetics - to increase HR and Force
- Parasympathetics - decrease HR
How do the sympathetic nerves get from the CNS to the heart
How do sympathetic singals reach organs
- Pre-synaptic neurones - trevel inferiorly down the spinal cord
- Exits the spinal cord in one of the T1/L2 nerves (thoraculumbar or sympathetic outflow)
- This can happen in 3 ways
- travel to the ganglion of the same level and synnapse
- Travel to a superior ganglion and synapse
- Travel to an inferior ganglion and synapse
How do post-synpatic neurones reach the Organs
- cardiopulmonary splanchic nerves
- Relay post-synaptic sympathetics out to the heart + other thoracic structures
- Cardiopulmonary splanchic nerves are bilateral for midline organs - left and right sympathetic innervation
What are the cardioplumonary splanchic nerves
post-synaptic sympathetic fibres from cervical and upper thoracic sympathetic chains
What is the location of the CPS nerves
behind the great vessels of the heart
What are the 3 different fibres within the cardiac plexus
- Sympathetic fibres
- Parasympathetic fibres- left and right from vagus
- Visceral afferent fibres
Are are the 2 types of visceral afferent fibres within the cardiac plexus
- Pain fibres relay via the sympathetic nervous system
- Baroreceptors - relay via parasympathetic nervous system
Anatomy of the cardiax plexus and CPS nerves
How do parasympathetic fibres get to spinal cord
- Cranial out flow
- Sacral outflow
What are the 4 nerves carrying the cranial outflow of the parassympathetic nervous system
- III - occulomoter
- VII - Facail
- IX - Glossopharyngeal
- X - Vagus
What is the function of the cranial outflow
What is different in parasympathetic innervation
- individual ganglia not in a chain like sympathetic
- The ganglia are common located on organ walls rather than paralelle to spinal cord
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What is the different between sympathetic post and pre ganlgion nerve fibres compared to parasympathetic
Summar of the sympathetic innervation
Sympathetic
- Dotted blue line – presynaptic fiber from ventral rootlet
- Travels to ganglion in the sympathetic chain
- Blue solid line = Post-synaptic neuron towards heart
- Fight or Flight
Parasympathetic
- Pink dotted line – Vagus nerve towards ganglion located in heart wall
- Post ganglionic fiber = short
- Vagal tone = continuous Aps to slow down heart rate
Visceral afferents
- Baroreceptor – contained within vagus nerve
- Pain – along site sympathetic fibers back towards CNS
- Cardiac visceral afferent accompany the sympathetic nerves
- Carried collectively in cardiopulmonary splanchnic nerve
