Anatomy of the Pericardium

Veins Draining into Right Atrium

• Superior vena cava: Drains deoxygenated blood from the head, neck, upper limbs, and thorax.
• Inferior vena cava: Drains deoxygenated blood from the lower limbs, abdomen, and pelvis.

Sympathetic Cardiac Innervation

• Function: Increases heart rate and contractility, leading to an increase in blood flow.

Lymphatic Drainage of the Heart

• Lymphatic vessels of the heart drain into the tracheobronchial lymph nodes.

Parasympathetic Effects on the Heart

• Vagal nerve stimulation: Decreases heart rate and contractility.

Cardiac Plexus Composition

• Sympathetic fibers: From the cervical and upper thoracic sympathetic trunk.
• Parasympathetic fibers: From the vagus nerve.

Spinal Cord Origin of Sympathetic Fibers for the Heart

• Thoracic segments T1-T4.

Sympathetic Impact on AV Node

• Increased conduction velocity: Accelerates impulse transmission through the AV node, leading to a faster heartbeat.

Conducting System of the Heart

• Role: Generates and transmits electrical impulses, coordinating the rhythmic contraction of the heart chambers.

Anterior Surface of the Heart

• Right ventricle: Forms the largest part of the anterior surface.

Right Ventricular Outflow Tract

• Conus arteriosus, also known as the infundibulum: Leads to the pulmonary trunk.

Right Ventricular Backflow Prevention

• Pulmonary valve: Prevents backflow of blood from the pulmonary trunk into the right ventricle.

Right Ventricular Papillary Muscles

• Three papillary muscles: Attached to the chordae tendineae, which support the tricuspid valve leaflets.

Right Ventricular Blood Source

• Right atrium: Receives deoxygenated blood from the superior and inferior vena cava.

Right Ventricular Papillary Muscle Characteristics

• Anterior papillary muscle: Largest and most prominent.

Right Ventricular Wall Separation

• Conus arteriosus: Separates the muscular inflow part of the right ventricle from its smooth wall.

Right and Left Ventricular Partition

• Interventricular septum: Muscular wall separating the right and left ventricles.

Fibrous Pericardium

• Primary Function: Provides structural support and anchors the heart within the mediastinum.

Fibrous Pericardium Attachment

• Anteriorly: Attaches to the diaphragm, sternum, and large blood vessels.

Structures Passing Through Fibrous Pericardium

• Superior vena cava, inferior vena cava, aorta, and pulmonary trunk.

Pericardial Sac Layers

• Pericardial cavity: Space between the parietal and visceral layers of the serous pericardium, filled with a small amount of lubricating fluid.

Fluid Accumulation in Pericardial Sac

• Pericardial effusion: Rapid accumulation of fluid in the pericardial sac can compress the heart, impairing its function.

Outer Heart Covering

• Fibrous pericardium: Forms the outer covering of the heart.

Fibrous Pericardium and Diaphragm

• Inferiorly: The fibrous pericardium blends with the central tendon of the diaphragm.

Pericardiacophrenic Ligament

• Pericardiacophrenic ligament: A continuation of the fibrous pericardium, extending from the fibrous pericardium to the diaphragm, providing support and attachment.

SA Node Function

• Pacemaker of the heart: Generates electrical impulses that initiate each heartbeat.

AV Node Location

• Inferior portion of the interatrial septum: Located near the opening of the coronary sinus.

Sympathetic Effect on SA Node

• Increased firing rate: Increases the frequency of impulses originating from the SA node, leading to a faster heart rate.

Atrial-Ventricular Myocardium Connection

• Bundle of His: Specialized conduction fibers that transmit electrical impulses from the AV node to the ventricles.

Purkinje Fiber Role

• Rapid conduction of impulses: Spread electrical impulses throughout the ventricles, ensuring coordinated contraction.

SA Node Impulse Frequency

• 60-100 beats per minute: Typical impulse generation rate in a healthy individual.

Conduction After SA Node Impulse

• Rapid conduction: Electrical impulse travels rapidly through the atrial myocardium and then to the AV node.

Interventricular Septum Junction

• Membranous and muscular parts: Junction of these parts allows for conduction of impulses from the AV node to the ventricles.

Right Sternum Heart Limit

• Third costal cartilage: Corresponds to the upper limit of the heart on the right side of the sternum.

Apex Beat Location

• Left ventricle: Corresponds to the apex beat, typically located in the fifth intercostal space, medial to the left midclavicular line.

Left Heart Margin

• Left ventricle and left atrium: Form the left margin of the heart.

Inferior Border and Left MCL

• Inferior border of the heart: Corresponds to the left midclavicular line (MCL) at the level of the fifth intercostal space.

T4 Vertebra Origin

• Aorta: Begins at the left side of the inferior border of the body of T4 vertebra.

Superior Vena Cava Entry Point

• Right atrium: Superior vena cava enters the heart at the superior border of the right atrium.

Superior Heart Border

• Right auricle, aorta, and pulmonary trunk: Form the superior border of the heart.

Right Heart Border

• Right atrium: Forms the right border of the heart, extending inferiorly to the fourth costal cartilage.

Explore the detailed anatomy of the fibrous and serous pericardium in this quiz. Understand their structure, functions, and connections to surrounding mediastinal structures. Test your knowledge about how these layers protect and stabilize the heart.