In Nature, fluids move in a spiral manner. It has therefore been suggested that the structure of the cardiovascular system is taking full advantage of this natural tendency of fluids to spiral. The rotary motion of the heart and blood was detected and measured by several researchers: As early asJames B.
The inferior tip of the heart, known as the apex, rests just superior to the diaphragm. Anatomy of the Heart anatomy Pericardium The heart sits within a fluid-filled cavity called the pericardial cavity. The walls and lining of the pericardial cavity are a special membrane known as the pericardium.
Pericardium is a type of serous membrane that produces serous fluid to lubricate the heart and prevent friction between the ever beating heart and its surrounding organs. Besides lubrication, the pericardium serves to hold the heart in position and maintain a hollow space for the heart to expand into when it is full.
The pericardium has 2 layers—a visceral layer that covers the outside of the heart and a parietal layer that forms a sac around the outside of the pericardial cavity.
Structure of the Heart Wall The heart wall is made of 3 layers: The epicardium is the outermost layer of the heart wall and is just another name for the visceral layer of the pericardium. Thus, the epicardium is a thin layer of serous membrane that helps to lubricate and protect the outside of the heart.
Below the epicardium is the second, thicker layer of the heart wall: The myocardium is the muscular middle layer of the heart wall that contains the cardiac muscle tissue.
Myocardium makes up the majority of the thickness and mass of the heart wall and is the part of the heart responsible for pumping blood. Below the myocardium is the thin endocardium layer.
Endocardium is the simple squamous endothelium layer that lines the inside of the heart. The endocardium is very smooth and is responsible for keeping blood from sticking to the inside of the heart and forming potentially deadly blood clots.
The thickness of the heart wall varies in different parts of the heart. The atria of the heart have a very thin myocardium because they do not need to pump blood very far—only to the nearby ventricles. The ventricles, on the other hand, have a very thick myocardium to pump blood to the lungs or throughout the entire body.
The right side of the heart has less myocardium in its walls than the left side because the left side has to pump blood through the entire body while the right side only has to pump to the lungs.
Chambers of the Heart The heart contains 4 chambers: The atria are smaller than the ventricles and have thinner, less muscular walls than the ventricles. The atria act as receiving chambers for blood, so they are connected to the veins that carry blood to the heart.
The ventricles are the larger, stronger pumping chambers that send blood out of the heart. The ventricles are connected to the arteries that carry blood away from the heart. The chambers on the right side of the heart are smaller and have less myocardium in their heart wall when compared to the left side of the heart.
This difference in size between the sides of the heart is related to their functions and the size of the 2 circulatory loops. The right side of the heart maintains pulmonary circulation to the nearby lungs while the left side of the heart pumps blood all the way to the extremities of the body in the systemic circulatory loop.
Valves of the Heart The heart functions by pumping blood both to the lungs and to the systems of the body. The heart valves can be broken down into two types: The atrioventricular AV valves are located in the middle of the heart between the atria and ventricles and only allow blood to flow from the atria into the ventricles.
The AV valve on the right side of the heart is called the tricuspid valve because it is made of three cusps flaps that separate to allow blood to pass through and connect to block regurgitation of blood. The AV valve on the left side of the heart is called the mitral valve or the bicuspid valve because it has two cusps.
The AV valves are attached on the ventricular side to tough strings called chordae tendineae. The chordae tendineae pull on the AV valves to keep them from folding backwards and allowing blood to regurgitate past them.
During the contraction of the ventricles, the AV valves look like domed parachutes with the chordae tendineae acting as the ropes holding the parachutes taut. The semilunar valves, so named for the crescent moon shape of their cusps, are located between the ventricles and the arteries that carry blood away from the heart.
The semilunar valve on the right side of the heart is the pulmonary valveso named because it prevents the backflow of blood from the pulmonary trunk into the right ventricle.
The semilunar valve on the left side of the heart is the aortic valvenamed for the fact that it prevents the aorta from regurgitating blood back into the left ventricle.
The semilunar valves are smaller than the AV valves and do not have chordae tendineae to hold them in place.Axis Scientific Human Heart Anatomy Model, Enlarged to 3 Times Life Size, Removable Aorta and Superior Vena Cava, Shows Internal Heart Structures, Includes Colorful Study Guide and 3 .
Basic anatomy and function of the heart The heart is a muscular organ that pumps blood to all the tissues in your body through a network of blood vessels. The human heart is an organ that pumps blood throughout the body via the circulatory system, supplying oxygen and nutrients to the tissues and removing carbon dioxide and other wastes.
Contrary to the official theory, findings from embryology and other sources have shown that the heart is not a mechanical pump pushing blood through the blood vessels but that the blood is instead propelled by its own biological force boosted by the heart.
Product Features 2-piece heart has labeled parts on one side and letters on the other. This is an emergency situation as it can precede a heart attack, serious abnormal heart rhythm, or cardiac arrest. Myocardial infarction (heart attack): A coronary artery is suddenly blocked.