Layer of heart

\( \newcommand\) • • Our exploration of more in-depth heart structures begins by examining the membrane that surrounds the heart, the prominent surface features of the heart, and the layers that form the wall of the heart. Each of these components plays its own unique role in terms of function. Membranes The membrane that directly surrounds the heart and defines the pericardial cavity is called the pericardium or pericardial sac. It also surrounds the “roots” of the major vessels, or the areas of closest proximity to the heart. The pericardium, which literally translates as “around the heart,” consists of two distinct sublayers: the sturdy outer fibrous pericardium and the inner serous pericardium. The fibrous pericardium is made of tough, dense connective tissue that protects the heart and maintains its position in the thorax. The more delicate serous pericardium consists of two layers: the parietal pericardium, which is fused to the fibrous pericardium, and an inner visceral pericardium, or epicardium, which is fused to the heart and is part of the heart wall. The pericardial cavity, filled with lubricating serous fluid, lies between the epicardium and the pericardium In most organs within the body, visceral serous membranes such as the epicardium are microscopic. However, in the case of the heart, it is not a microscopic layer but rather a macroscopic layer, consisting of a simple squamous epithelium called a mesothelium, reinforced with loose, irregular, or areolar con...

The heart is a hollow, muscular organ that pumps oxygenated blood throughout the body and deoxygenated blood to the lungs. This key circulatory system structure is comprised of four chambers. One chamber on the right receives blood with waste (from the body) and another chamber pumps it out toward the lungs where the waste is exhaled. One chamber on the left receives oxygen-rich blood from the lungs and another pumps that nutrient-rich blood into the body. Two valves control blood flow within the heart’s chambers, and two valves control blood flow out of the heart. 1. The Heart Wall Is Composed of Three Layers The muscular wall of the heart has three layers. The outermost layer is the epicardium (or visceral pericardium). The epicardium covers the heart, wraps around the roots of the great blood vessels, and adheres the heart wall to a protective sac. The middle layer is the myocardium. This strong muscle tissue powers the heart’s pumping action. The innermost layer, the endocardium, lines the interior structures of the heart. 2. The Atria Are the Heart’s Entryways for Blood The left atrium and right atrium are the two upper chambers of the heart. The left atrium receives oxygenated blood from the lungs. The right atrium receives deoxygenated blood returning from other parts of the body. Valves connect the atria to the ventricles, the lower chambers. Each atrium empties into the corresponding ventricle below. 3. Each Heart Beat Is a Squeeze of Two Chambers Called Ventricle...

Anatomy Where are the coronary arteries located? Your coronary arteries are around and inside your Coronary artery structure There are two coronary arteries, each containing several branches: • Right coronary artery (RCA): The RCA supplies blood to your right atrium and right ventricle (where deoxygenated blood goes before heading to the lungs). Its branches supply the sinoatrial (SA) and atrioventricular (AV) nodes. These nodes send electrical signals through your heart, so the heart muscles know when to contract. Branches of the RCA also deliver blood to one-third of your interventricular septum, which is the wall between your heart’s two lower chambers. • Left main coronary artery (LMCA): The LMCA supplies blood to your left atrium and left ventricle. This is where oxygenated blood arrives from your lungs before your heart pumps it out to the rest of your body. Its branches supply blood to the other two-thirds of your interventricular septum. Is the structure of the coronary artery always the same? It’s important to note that sometimes the structure of the coronary artery branches varies from person to person. Some examples are: • Coronary arteries are usually surrounded by a layer of fat but in some people the arteries are within the heart muscle itself. • Blood supply to the SA and AV nodes comes from the LCMA, not the RCA, in about 10% of people. • Sometimes a single coronary artery arises from the aorta, then divides into right and left branches. Most of these varia...

Your pericardium is a fluid-filled sac that surrounds your heart and the roots of the major blood vessels that extend from your heart. Conditions that affect your pericardium include pericarditis, pericardial effusion and constrictive pericarditis. Symptoms of pericardial problems include chest pain, shortness of breath and heart palpitations. Overview What is the pericardium? Your pericardium is a protective, fluid-filled sac that surrounds your Your pericardium also covers the roots of your major blood vessels as they extend from your heart. These are known as your “great vessels,” and they include your: • • Main • Pulmonary veins. • Superior and inferior Function What are the functions of the pericardium? Your pericardium has several important functions. These include: • Cushioning your heart from outside forces and pressure. • Holding your heart in place. • Keeping your heart from expanding too much and filling with too much blood. • Protecting your heart from infections. • Providing lubrication to reduce friction between your heart and surrounding tissues. Anatomy Where is the pericardium located? Your pericardium is located in your chest, where it surrounds your heart. Your heart is located in the front of your chest, slightly to the left of your breastbone (sternum). If you have What are the layers of the pericardium? Your pericardium has two main layers: • Fibrous pericardium: This is the tough, outermost layer of your pericardium. It’s made of connective tissue th...

Synonyms: Tricuspid valve, Valva tricuspidalis Understanding heart valves anatomy is important in grasping the overall function of the The contents of the left and right side of the heart are isolated from each other by the respective interventricular septa. Similarly, blood is separated from the atrial and ventricular parts of the heart by the atrioventricular septa. However, it is the heart valves that allow blood to pass from the Key facts about the heart valves Tricuspid Right atrioventricular valve Three cusps - anterior (anterosuperior), septal, and posterior (inferior) Associated with four papillary muscles - anterior, medial or septal, inferior, moderator band (septomarginal trabecula) Prevents blood from flowing from the right ventricle into the right atrium Mitral Left atrioventricular valve Two cusps - anterior (aortic, greater, anteromedial or septal) and posterior (ventricular, mural, posterolateral, or smaller)Â Associated with posteromedial and anterolateral papillary muscles Prevents blood from flowing from the left ventricle into the left atrium Pulmonary Right semilunar valve Three semilunar cusps - anterior (non-adjacent), right (right adjacent), and left (left adjacent) No associated papillary muscles Prevents backflow of blood from pulmonary circulation into the right ventricle Aortic Left semilunar valve Three semilunar cusps - right coronary (anterior), left coronary (left posterior), and a non-coronary cusp (right posterior, non-adjacent) No associa...

The pericardium has a few important roles: • It keeps your heart fixed in place within your chest cavity. • It prevents your heart from stretching too much and overfilling with blood. • It lubricates your heart to prevent friction with the tissues around it as it beats. • It protects your heart from any infections that might spread from nearby organs like the lungs. The pericardium has two layers: • Fibrous pericardium is the outer layer. It’s made from thick connective tissue and is attached to your diaphragm. It holds your heart in place in the chest cavity and protects from infections. • Serous pericardium is the inner layer. It’s further divided into two more layers: the visceral and parietal layers. The serous pericardium helps to lubricate your heart. In between these two layers is the fluid-filled pericardial cavity. It lubricates the heart and protects it from injury. Possible causes of pericardial effusion include: • diseases that cause inflammation, such as • severe underactive thyroid ( • infections • recent heart surgery • cancer that has spread to your pericardium • kidney failure Symptoms of pericardial effusion include: • chest pressure or pain • shortness of breath • difficulty breathing when you lie down • nausea • a feeling of fullness in your chest • trouble swallowing The excess fluid from pericardial effusion can cause intense pressure on your heart and damage it. A pericardial cyst is a noncancerous, fluid-filled growth in the pericardium. This type o...

\( \newcommand\) • • • • • • The pericardium is a thick, membranous, fluid-filled sac which encloses, protects, and nourishes the heart. Key Points • The pericardium is a mesothelium tissue of the thoracic cavity which surrounds the heart. The outer layer, the fibrous pericardium, is comprised of dense connective tissue that protects the heart, anchors it to the surrounding walls, and prevents it from overfilling. • The inner layer of the pericardium, the serous pericardium, is further divided into two layers, an outer parietal layer and an inner visceral layer with the pericardial cavity in between the two layers. • The serous pericardium functions to lubricate the heart with pericardial fluid, which is stored in the space between the parietal and visceral layers. • Pericarditis is inflammation of the pericardium, often due to infection, which can constrict and put harmful pressure on the heart. Key Terms • fibrous pericardium: Composed of dense connective tissue which protects the heart, anchors it to the surrounding walls, and prevents the heart from overfilling with blood. • serous pericardium: Located deeper than the fibrous pericardium, this structure contains two layers that lubricate the heart to prevent friction from occurring during heart activity. • pericardium: A serous membrane that surrounds and protects the heart. The pericardium is the thick, membranous, fluid-filled sac that surrounds the heart and the roots of the vessels that enter and leave this vital o...