the nerve supply of the human heart with clinical applied
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Share You said: nerve supply of heart in 100 words ChatGPT said: The heart receives its nerve supply from both the autonomic nervous system (ANS), which includes the sympathetic and parasympathetic divisions. The sympathetic fibers originate from the T1-T5 spinal segments, travel through the cardiac plexus, and increase heart rate and contractility. The parasympathetic fibers, primarily from the vagus nerve (CN X), slow the heart rate by acting on the sinoatrial (SA) and atrioventricular (AV) nodes. The cardiac plexus, located near the aortic arch and tracheal bifurcation, integrates these inputs. Additionally, the heart has an intrinsic conduction system (SA node, AV node, Bundle of His, and Purkinje fibers) for coordinated contraction.
the nerve supply of the human heart with clinical applied
- 1. NERVE SUPPLY AND CONDUCTING SYSTEM OF HEART Dr. Padamjeet Panchal
- 2. Basic arrangement of sympathetic pathway T2-T5
- 3. Thoracic part of sympathetic trunk
- 4. Nerve Supply of the Heart •The heart is supplied by nerves passing through • the superficial and • deep cardiac plexuses.
- 5. Nerve Supply of the Heart • Parasympathetic preganglionic neurons from dorsal nucleus of the vagus for the heart are located in the medulla oblongata of the brain. • They reach the heart through cardiac branches of the vagus and convey impulses of pain produced as a result of anoxia of heart muscle (angina) • Parasympathetic postganglionic neurons are located within the superficial and deep cardiac plexuses and also in the walls of atria.
- 6. Nerve Supply of the Heart • Preganglionic sympathetic neurons are located in segments T1 to T5 of the cord. • On reaching, the sympathetic trunk their axons synapse with postganglionic neurons in the upper thoracic ganglia. • Some of them run upwards in the sympathetic trunk to end in cervical ganglia Postganglionic sympathetic fibres leave these ganglia through their cardiac branches and join the vagal fibres in forming the cardiac plexuses.
- 7. The superficial cardiac plexus is located just below the arch of the aorta, close to the ligamentum arteriosum. The deep cardiac plexus is situated in front of the bifurcation of the trachea.
- 10. • Parasympathetic nerves reach the heart via the vagus. These are cardioinhibitory. HR ↓ • Sympathetic nerves are derived from the T4-5 spinal segments of the spinal cord. These are cardio-acceleratory. HR ↑ and dilates co.A’s. NERVE SUPPLY OF HEART
- 11. • The superficial cardiac plexus is formed by • the inferior cervical cardiac branch of the left vagus nerve, • the superior cervical cardiac branch of the left sympathetic trunk. • The deep cardiac plexus receives several branches from the right and left vagus nerves as follows. • Right superior and inferior cervical cardiac branches. • Left superior cervical cardiac branch. • Branches from right and left vagi arising in the thorax. • Branches from the right and left recurrent laryngeal nerves. • The plexus also receives numerous cardiac branches from the right and left sympathetic trunks. NERVE SUPPLY OF HEART
- 12. Formation of superficial and deep cardiac plexuses Deep Cardiac Plexus Superficial Cardiac Plexus
- 13. CLINICAL ANATOMY • Cardiac pain is an ischaemic pain caused by incomplete obstruction of a coronary artery. • Viscera usually have low amount of sensory output, whereas skin is an area of high amount of sensory output. So pain arising from low sensory output area is projected as coming from high sensory output area.
- 14. FACTS TO REMEMBER • Pain of heart due to myocardial infarction is referred to left side of chest between 3rd and 6th intercostal spaces. It also get extended to medial side of left upper limb in the area of distribution of C8 and T1 spinal segments.
- 15. Conducting System The conducting system is made up of myocardium that is specialised for initiation and conduction of the cardiac impulse. Its fibres are finer than other myocardial fibres, and are completely cross-striated. The conducting system has the following parts. 1. Sinuatrial node or SA node 2. Atrioventricular node or AV node 3. Atrioventricular bundle or AV bundle or bundle of His 4. Right branch of the AV bundle 5. Left branch of the AV bundle 6. The Purkinje fibres form a subendocardial plexus
- 16. Arterial Supply to the Conduction System • The sinoatrial node may sometimes be supplied by the left coronary artery. • The right bundle branch of the AV bundle is supplied by the left coronary artery. • The sinoatrial node, the atrioventricular node and the atrioventricular bundle are supplied by the right coronary artery. • The right bundle branch of the AV bundle is supplied by the left coronary artery. • The left bundle branch derives blood from both the arteries.
- 17. The conducting system of the heart
- 18. Sinoatrial node (SA node): • This is a small area in the wall of the right atrium along the anterior margin of the opening of the superior vena cava. • The greater part of the node lies in the sinus venarum part of the atrium • anteriorly it extends into the crista terminalis. • The node gives rise to spontaneous electrical impulses which spread throughout the atrial musculature of both sides causing it to contract.
- 19. Atrioventricular node (AV node): • This is situated in the lower part of the interatrial septum just above the attachment of the septal cusp of the tricuspid valve and the opening of the coronary sinus. • Some of the impulses generated in the SA node, as they pass through the atrial musculature, reach the AV node.
- 20. Atrioventricular bundle (AV bundle or Bundle of His) • Arising from the AV node. • passes forwards in the interatrial septum, between the right side of the septum and the septal cusp of the tricuspid valve • reaches the membranous part of the interventricular septum. • descends to the upper rim of the muscular septum and divides into right and left branches. • The bundle is the only pathway through which the atrial musculature and the ventricular musculature are connected • only route through which impulses from atria reach the ventricles.
- 21. Branches of the bundle: • The right bundle branch (orthe right crus) runs downwards and forwards on the right side of the muscular part of the interventricular septum, towards the apex of the heart. • It passes through the septomarginal trabecula to reach the base of the anterior papillary muscle. • The left bundle branch (or the left crus) pierces the septum, descends on its left side beneath the endocardium and divides into anterior and posterior branches.
- 22. Purkinje fibres: • Conduction myofibres, of the conduction system • form a dense network deep to the endocardium of the ventricular chambers. • The branches of the bundle, at the bases of the papillary muscles divide into smaller branches which continue into the Purkinje plexus. • The entire musculature of both the ventricles are ramified by the Purkinje network.
- 23. Working of conduction system • The conduction system is made up of specialised tissue that has a partial resemblance to the structure of cardiac muscle. • This tissue conducts impulses faster than cardiac muscle but slower than regular nerve fibres. • Impulses arising in the SA node and spreading into the atrial musculature cause the atria to contract. • These impulses reach the AV node, pass through the AV bundle and its branches to reach the ventricular muscle.
- 24. Working of conduction system • Conduction through the AV node, AV bundle, bundle branches and Purkinje fibres takes time. • As a result, the atrial contraction is followed by the ventricles after a definite interval. • Within the ventricles themselves, the papillary muscles are the first to contract ensures closure of the AV valves before the ventricles contract.
- 25. Specialised internodal pathways • some workers explain their presence . All of them are within the right atrial wall. • Anterior internodal pathway: It starts at the anterior end of the SA node and extends to the AV node anterior to the superior venacaval opening. • Middle internodal pathway: it starts at the posterior end of the SA node and extends to the AV node posterior to the superior venacaval opening. • Posterior internodal pathway: It starts at the posterior end of the SA node and extends to the AV node through the crista terminalis and the valve of the inferior venacaval opening;