The Anatomy of the Cardiovascular System 1 and 2 Flashcards
What is the mediastinum, and how is it subdivided?
The mediastinum is the central compartment of the thoracic cavity. It is divided into:
Superior mediastinum (contains great vessels, trachea, esophagus, thymus)
Inferior mediastinum, which is further divided into:
Anterior (thymus remnants, lymph nodes, fat)
Middle (heart, pericardium, great vessel roots)
Posterior (esophagus, thoracic aorta, azygos vein, thoracic duct, vagus nerve)
What is the anatomical position of the heart?
The heart is located in the middle mediastinum, tilted slightly left, with:
The apex pointing downward and left at the 5th intercostal space
The base at the level of T6-T9 vertebrae
Positioned between the lungs and anterior to the vertebral column
What are the great vessels of the heart and their connections?
Pulmonary trunk → From right ventricle → To lungs
Pulmonary veins (4) → From lungs → To left atrium
Aorta → From left ventricle → To systemic circulation
Superior vena cava → From upper body → To right atrium
Inferior vena cava → From lower body → To right atrium
What are the layers of the pericardium and their innervation?
Fibrous pericardium (outer layer) – Innervated by phrenic nerve
Serous pericardium (inner layer), consisting of:
Parietal layer – Also innervated by phrenic nerve
Visceral layer (epicardium) – Innervated by autonomic nerves
What are the three tissue layers of the heart wall?
Endocardium – Inner lining, smooth endothelial tissue
Myocardium – Thick muscular layer, contains cardiac muscle fibers
Epicardium – Outer layer, same as visceral pericardium
What is the fibrous skeleton of the heart?
A dense connective tissue structure that:
- Supports valves and cardiac muscle
- Electrically isolates atria from ventricles
- Provides a rigid attachment for muscle fibers
What are the external features of the heart?
Borders – Right, left, superior, inferior
Surfaces – Sternocostal, diaphragmatic, left pulmonary
Grooves (Sulci) – Coronary sulcus, anterior and posterior interventricular sulci
Chambers – Right atrium, right ventricle, left atrium, left ventricle
What is the arterial supply of the heart?
Coronary circulation:
- Right coronary artery (RCA) → Supplies right atrium, right ventricle, SA node
- Left coronary artery (LCA) → Divides into:
Left anterior descending artery (LAD) – Supplies anterior heart
Circumflex artery – Supplies left atrium, lateral left ventricle
How does the heart drain venous blood?
Via cardiac veins into the coronary sinus, which empties into the right atrium.
Main veins:
Great cardiac vein – Runs with LAD artery
Middle cardiac vein – Runs in posterior interventricular sulcus
Small cardiac vein – Runs along the right coronary artery
How is the heart drained by the lymphatic system?
Lymph drains into tracheobronchial lymph nodes, which ultimately drain into the thoracic duct (left side) or right lymphatic duct (right side).
What are the intrinsic and extrinsic innervations of the heart?
Intrinsic: SA node (pacemaker), AV node, His bundle, Purkinje fibers
Extrinsic:
Sympathetic (T1-T5) – Increases heart rate and force
Parasympathetic (Vagus nerve) – Decreases heart rate
What are the internal features of the heart?
Chambers: Right atrium, right ventricle, left atrium, left ventricle
Valves:
Atrioventricular (tricuspid & mitral)
Semilunar (aortic & pulmonary)
Chordae tendineae – Connect valves to papillary muscles
Where are the surface markings for the apex beat and heart valves?
Apex beat → 5th intercostal space, midclavicular line
Valve auscultation areas:
- Aortic valve → 2nd right intercostal space
- Pulmonary valve → 2nd left intercostal space
- Tricuspid valve → 4th left intercostal space
- Mitral valve → 5th left intercostal space, midclavicular
What are some key clinical considerations of the heart and pericardium?
Pericarditis → Inflammation of the pericardium
Cardiac tamponade → Excess fluid in pericardial sac compressing heart
Coronary artery disease → Blockage of coronary circulation
Valve diseases → Stenosis or regurgitation of heart valves
