Gross Anatomy of the Heart

Gross Anatomy of the Heart

• Located between the lungs, behind and slightly to the left of the breastbone (sternum)
• Surrounded by a double-layered membrane called the pericardium
• Pericardium forms a sac-like structure, enclosing the heart
• Outer layer of the pericardium surrounds the roots of the heart's major blood vessels and is attached to the spinal column, diaphragm, and other body parts.
• Inner layer of the pericardium is attached to the heart muscle.
• A coating of fluid separates the two pericardial layers, allowing the heart to move freely within the sac during contraction, without being detached from the body.

The Heart in a Plain Chest X-Ray

• Imaging demonstrates the heart's position and its relationship to other structures within the chest region.
• Annotations may be included to identify key structures and landmarks of the cardiovascular system.

MRI, Coronary Angiogram, and 3-D Reconstruction

• Advanced imaging techniques for visualizing the heart and its vasculature
• Medical procedures are used to obtain highly detailed anatomical information of heart structures and blood vessels, providing information about the coronary arteries, chambers, and walls of the heart.

Anatomical Position of the Heart

• The heart is located within the mediastinum, the central compartment of the thoracic cavity
• Surrounded by the lungs
• Rests on the diaphragm and is positioned between the two lungs within the thoracic cavity.

The Diaphragm

• Muscles supporting the lower portion of the heart are part of the diaphragm.
• Vertebral, costal, and sternal muscular parts
• Contains major structures like the aorta, esophagus, and inferior vena cava.
• The diaphragm has a tendinous center, significant for its morphology.

Some Technical Data

• Heart weight: 7-15 ounces (200-425 grams)
• Sized roughly like one's fist
• Throughout a lifetime, the average heart may beat: more than 3.5 billion times.
• Daily heartbeats: approximately 100,000
• Daily blood pumped: approximately 2,000 gallons (7,571 liters)

Layers of the Cardiac Wall

• Endocardium: Innermost layer
• Myocardium: Middle layer, thick muscular layer of the heart
• Epicardium: Outermost layer, also called the visceral pericardium, which is part of the pericardium.
• Pericardial Cavity: The space between the parietal and visceral pericardium, filled with fluid for reduced friction.

Muscle Tissue Types

• Smooth Muscle Tissue: Involuntary control in organs, like your digestive system
• Cardiac Muscle Tissue: Involuntary control, specific to the heart
• Skeletal Muscle Tissue: Voluntary control in limbs, like your arms and legs.

Muscle Tissue Types (Detailed)

• Skeletal muscle: Voluntary, striated, and multinucleated
• Cardiac muscle: Involuntary, striated, and uninucleated, interconnected by intercalated discs
• Smooth muscle: Involuntary, non-striated, and uninucleated

The Heart's Chambers

• Atria: Upper chambers (right and left).
• Ventricles: Lower chambers (right and left)
• Septum: Muscular wall separating atria and ventricles
• Left ventricle: Largest and strongest chamber, responsible for pumping oxygenated blood to the body
• Walls are relatively thin, but generate sufficient force to pump blood through the aortic valve.

The Four Chambers of the Heart

• Illustrations show direction of blood flow within the heart
• Key structures labelled, including atria, ventricles, the pulmonary and aortic valves

Right Atrium

• Receives de-oxygenated blood from the body.
• Blood enters from the superior and inferior vena cava
• Sinoatrial node triggers coordinated contraction of the atrium
• Blood moves through the tricuspid valve into the right ventricle

Right Ventricle

• Receives de-oxygenated blood from the right atrium
• Pulmonary valve controls flow into the pulmonary artery
• Contraction forces blood into the arteries, traveling to the lungs

Left Atrium

• Receives oxygenated blood from the lungs through pulmonary veins
• Blood flows into the left ventricle via the mitral valve.

Left Ventricle

• Receives oxygenated blood from the left atrium
• Blood flows through the aortic valve.
• Contraction of the ventricle forces blood into the aorta.
• Blood flows throughout the body.

Systemic and Pulmonary Circulation

• Systemic circulation: Carries oxygenated blood from the heart to the body and returns de-oxygenated blood.
• Pulmonary circulation: Carries de-oxygenated blood from the heart to the lungs and returns oxygenated blood.

Cardiac Valves

• Four valves regulate blood flow within the heart
• Tricuspid, pulmonary, mitral, and aortic valves
• Each valve ensures one-way blood flow

Anatomy: Mitral Valve

• Description of the mitral valve's structure and function
• Composed of the left atrial wall, the annulus, the leaflets, the chordae tendineae, the papillary muscles, and the left ventricular wall

Anatomy: Pulmonary Valve

• Structure and function of the pulmonary valve are described and illustrated by diagrams.

Four Cardiac Valve descriptions

• Comprehensive anatomical discussion of the four cardiac valves (tricuspid, pulmonary, mitral and aortic)

Arteries and Veins

• Components of arteries and veins are shown
• Key characteristics are highlighted
• Layers of arteries and veins are displayed, including the tunica intima, media, and adventitia.

Aorta

• The largest blood vessel in the body.
• Carries oxygen-rich blood from the left ventricle to the rest of the body

Pulmonary Artery

• Carries de-oxygenated blood from the right ventricle to the lungs

Pulmonary Vein

• Carries oxygenated blood from the lungs to the left atrium

Heart's Blood Supply (Coronary Arteries)

• The heart receives blood from coronary arteries, which branch from the aorta.
• These arteries are essential for supplying the heart's own oxygen-rich blood, supplying oxygen and nutrients to cardiac muscle tissue