HSF - Anatomy - Innervation of the heart
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73 terms
Terms | Definitions |
|---|---|
 Nervous system subdivisions | CNS PNS |
| CNS includes | brain and spinal cord |
| PNS includes | Cranial Nerves and ganglia • Spinal nerves and ganglia |
| Spinal Nerve roots | Dorsal and Ventral |
| Dorsal root of spinal nerve | contains visceral and somatic AFFERENT fibers |
| DRG | contains cell bodies of somatic and visceral afferent nerve fibers |
| Ventral root of spinal nerve | contains somatic and visceral efferent fibers |
| Lateral Horn | contains cell bodies visceral efferent fibers |
| Ventral Horn | contains somatic efferent fibers |
| Spinal nerve contains | both sensory and motor nerve fibers |
| functional components of spinal nerve | General Somatic Afferent General Visceral Afferent General Somatic Efferent General Visceral Efferent |
| General Somatic Afferent | carries sensations from body wall to spinal cord: pain, touch, temp proprioception and pressure |
| General Visceral Afferent | carries sensations from viscera to spinal cord: mucous membranes glands blood vessels and smooth muscles and cardiac muscles |
| General Somatic Efferent | motor information from spinal cord to skeletal muscles |
| General Visceral Efferent | motor information from spinal cord to cardiac muscle, smooth muscles of viscera and glands |
| ANS branches | includes Sympathetic and Parasympathetic branches - together maintain homeostasis |
| ANS innervation | vesceral organs, BVs and secretory glands |
| ANS controlling centers | HT and Brain stem |
| Differences between PS ANS and S ANS | anatomical, neurotransmitters, physiological effects |
| Sympathetic Nervous system | acts in sympathy with emotions; fight or flight; more extensive of the ANS branches, ratio of afferent to efferent is 1 to 17; |
| effects of sympathetic nervous system | increased HR, dilated pupils, constricted arterioles in skin and intestine, dilated muscular arterioles, high BP, pale face, dry mouth, hair stands up, blood rushes to brain heart and skel muscle preferentially, closed alimentary and urinary tract sphincters, bronchi and bronchioles dilated |
| Sympathetic chain | where pre and post ganglionic neurons interface |
| Intermediolateral cell column | Lateral Horn from T1-L2, contains cell bodies of preganglionic afferent sympathetic neurons |
| Preganglionic sympathetic neurons pathway | myelinated neurons with cell bodies in Lateral horn, that leave the spinal cord in ventral root, join the afferent sensory fibers in spinal cord after DRG, pass via white rami communicantes to paravertebral ganglia of sympathetic trunk. |
| From sympathetic trunk ganglia, efferent sympathetic fibers: | synapse with excitor neuron/postganglionic sympathetic neuron in the ganglion |
| postganglionic sympathetic neurons | non-myelinated neurons that leave the ganglion and pass to spinal nerves as gray rami communicantes to spinal nerve and distributed to smooth muscles in wall of blood vessles, sweat glands arrector pili, |
| white and grey rami communicantes | the connections between preganglionic visceral efferent fibers and post ganglionic visceral efferent fibers to and from the spinal cord, white is pre- grey is post-ganglionic. |
| Splanchnic nerves | formed by efferent preganglionic sympathetic neurons that do not synapse on postganglionic neurons until closer to the effector organ |
| Greater splanchnic nerve | T5 to T9. pierces the crus of diaphragm and synapses at ganglia of celiac plexus, renal plexus and suprarenal medulla |
| Lesser Splanchnic nerve | T10 to T11. descends with greater splanchnic nerve synapses on post-ganglionic fibers in lower part of celiac ganglia |
| Least Splanchnic Nerve | T12. pierces diaphragm and synpases at ganglia of renal plexus |
| Cervical Ganglion | where T1 to T4 preganglionic sympathetic efferent fibers synapse with post-galglionic sympathetic fibers |
| cervical postganglionic sympathetic grey fibers | innervate smooth msucels and glands of head neck and upper extremities and heart |
| Parasympathetic Nervous system outflow | cranial nerves and sacral nerves 2-3-4 |
| Parasympaathetic effect | reverses the change from sympathetic innervation. rest and digest; slower HR, pupils constricted, secretion of saliva and intestinal juices, sphincters relaxes, bladder contracts, glycogen synthesis allowed |
| Parasympathetic preganglionic cell bodies | located in brain stem and grey matter of sacral segments of spinal cord S2,3,4 |
| Brainstem cells located in the | occulomotor nerve, facial nerve, glossopharyngeal nerve, Vagus nerve |
| ratio of pre to post ganglionic PARASYMPATHETIC fibers | 1 to 3 |
| ratio of pre to post ganglionic SYMPATHETIC fibers | 1 to 17 |
| Cardiac plexus | located below the arch of the aorta, formed by sympathetic and parasympathetic nerves |
| sympathetic innervation of the heart | from upper 5-6 segments of thoracic spinal cord lateral horn |
| preganglionic neurons innervating the heart end | in the cervical and third and fourth thoracic sympatehtic ganglia |
| cervical and third and fourth thoracic sympathetic ganglia | where upper 5-6 thoracic spinal segments' sympathetic pregangionic nerves synapse on postganglionic fibers. from here, postganglionic fibers go bilaterally to the heart |
| Parasympathetic innervation of the heart | vagus nerve |
| sympathetic innervation of the heart terminates on | SA node, AV node, cardiac muscle cells, coronary arteries |
| Effects of sympathetic stimulation of the heart | cardiac acceleration, increased force of contraction, dilation of coronary arteries, |
| adrenergic stimulation of SA node results in | rate of depolarization of pm cells, increase in atrioventricular conduction |
| Parasympathetic nerves of the heart terminate on | SA node, AV node, Coronary arteries |
| PS activation effects on heart | HR slows, force of contraction less, constriction of coronary arteries. net saves energy |
| mechanism of PS post synaptic innervation | acetylcholine binds muscarinic receptors to slow rate of depolarzation of PM cells and atrioventricular conduction and decreases contractility |
| Cardiac Plexuses | superficial and deep |
| Superficial Cardiac Plexus | inferior to aortic arh between aortic arch and pulmonary trunk |
| deep cardiac plexus | between aortic arch and trachial bifurcation |
| spinal thoracic segments innervating heart | T1 to T5 or T6 |
| SA node function | initiates contraction of the heart |
| SA node location | subendothelial layer of heart at juntion of SVC and right atrium near superior end of crista terminalis |
| SA node Heart rate | 70 beats per minute |
| SA node signal sent to | myocardial tissue of both atria |
| SA node positive and negative innervation by | sympathetic and parasympathetic nervous system |
| AV node location | internal, inferior aspect of interatrial septum near opening of coronary sinus |
| AV node receives signal from | SA node |
| AV node transmits signal | from SA node to AV bundle of His. down through fibrous skeleton of heart along membranous part of interventricular septum |
| Purkinje fibers | where AV bundle branches split and extend to walls of ventricles |
| right bundle branch of AV bundle of His stimulates: | muscles of interventricular septum, Anterior papillary muscle, wall of right ventricle |
| moderator band | carries electrical signal from right bundle of his (interventricular septum muscles) to anterior papillary muscle |
| Left bundle of His stimulate: | interventricular septum muscles, anterior and posterior papillary msucles and wall of left ventricle |
| referred pain | pain perceived at different location than its source |
| zone of referred pain | where somatic sensory neurons that share spinal ganglion with visceral sensory neurons terminate on skin |
| Cardiac referred pain | pain in upper left limb because of nerves of brachioplexus that shares the spinal cord segments |
| ganglion shared with cardiac sensory nerves | T1 through T4 or T5 |
| angina pectoris | radiates from substernal and left pectoral regions to left shoulder and medial aspect of left upper limb |
| part of limb that is stimulated in angina from which nerves? | medial cutaneous nerve of the arm, medial cutaneous nerve of the forearm, ulnar nerves |
| coronary arteries | T1 through T3 shared by upper limb cutanous nerves |
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