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- The heart is composed of smooth muscle. It has four chambers which contract in a specific order, allowing the human heart to pump blood from the body to the lungs and back again with high efficiency. The heart also contains “pacemaker” cells which fire nerve impulses at regular intervals, prompting the heart muscle to contract.
biologydictionary.net/heart/Heart (Human Anatomy): Overview, Function & Structure | Biology
Oct 4, 2019 · In most people, the heart is located on the left side of the chest, beneath the breastbone. The heart is composed of smooth muscle. It has four chambers which contract in a specific order, allowing the human heart to pump blood from the body to the lungs and back again with high efficiency.
Oct 31, 2024 · Heart, organ that serves as a pump to circulate the blood. It may be as simple as a straight tube, as in spiders and annelid worms, or as complex as the four-chambered double pump that is the center of the circulatory system in humans, other mammals, and birds.
- The Editors of Encyclopaedia Britannica
- In humans, the heart is situated between the two lungs and slightly to the left of center, behind the breastbone. It rests on the diaphragm, the mu...
- The heart consists of several layers of a tough muscular wall, the myocardium. A thin layer of tissue, the pericardium, covers the outside, and ano...
- The pumping of the heart, or the heartbeat, is caused by alternating contractions and relaxations of the myocardium. These contractions are stimula...
- The rhythmic noises accompanying the heartbeat are called heart sounds. The two distinct sounds are heard, a low, slightly prolonged “lub” (first s...
Nov 10, 2024 · The heart is a four-chambered muscular organ with a complex structure that allows it to efficiently pump blood throughout the body. It is divided into two halves—the right and left sides—each responsible for different aspects of circulation. The heart consists of four chambers: the right atrium, right ventricle, left atrium, and left ventricle.
- 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 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.
- Each Heart Beat Is a Squeeze of Two Chambers Called Ventricles. The ventricles are the two lower chambers of the heart. Blood empties into each ventricle from the atrium above, and then shoots out to where it needs to go.
- The Valves Are Like Doors to the Chambers of the Heart. Four valves regulate and support the flow of blood through and out of the heart. The blood can only flow one way—like a car that must always be kept in drive.
- Location of the Heart. The human heart is located within the thoracic cavity, medially between the lungs in the space known as the mediastinum. Figure 19.2 shows the position of the heart within the thoracic cavity.
- Shape and Size of the Heart. The shape of the heart is similar to a pinecone, rather broad at the superior surface and tapering to the apex (see Figure 19.2).
- Chambers and Circulation through the Heart. The human heart consists of four chambers: The left side and the right side each have one atrium and one ventricle.
- Membranes, Surface Features, and Layers. 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.
Sep 4, 2022 · As the central part of the circulatory system, the heart is responsible for pumping blood, supplying oxygen and nutrients, and removing metabolic waste such as carbon dioxide from all the...
Your heart’s main function is to move blood throughout your body. Blood brings oxygen and nutrients to your cells. It also takes away carbon dioxide and other waste so other organs can dispose of them. Your heart also: Controls the rhythm and speed of your heart rate. Maintains your blood pressure.
