Also known as What Is the Heart? Your heart is a muscular organ that pumps blood to your body. Your heart is at the center of your circulatory system.
The inferior tip of the heart, known as the apex, rests just superior to the diaphragm. Anatomy of the Heart Pericardium Heart anatomy 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.The eighth season of the American television medical drama Grey's Anatomy, commenced airing on the American Broadcasting Company (ABC) on September 22, , with a special two-hour episode and ended on May 17, with the eighth season having a total of 24 episodes.
The season was produced by ABC Studios, in association with Shondaland Production Company and The Mark Gordon . Feb 10, · Introduction to the circulatory system and the heart.
Created by Sal Khan. Watch the next lesson: ashio-midori.com Size.—The heart, in the adult, measures about 12 cm.
in length, 8 to 9 cm. in breadth at the broadest part, and 6 cm. in thickness. Its weight, in the male, varies from to grams; in the female, from to grams. The heart continues to increase in weight and size up to an advanced. 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.
Heart: A powerful muscle slightly larger than a clenched fist. It is composed of four chambers, two upper (the atria) and two lower (the ventricles).
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.