Heart Anatomy and Physiology
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Structure and function of the human heart
The size of a fist, the human heart is protected beneath the rib cage. Made of a specialized and unique muscle tissue, it pumps life throughout the body, driven by electrical impulses controlled by the brain and hormones. Understanding the heart's basic anatomy and function is important to understanding diseases that involve not only the heart, but also the lungs, kidneys, circulatory system, and brain.
Learn more about this amazing organ below.
Contents at a Glance
Anatomical Terminology
- Cardiac: dealing with the heart
- Myocardium: the heart tissue, it is made up of cells called myocytes
- Endocardium: interior heart muscle
- Pericardium: around the heart, such as the pericardial sac, a membrane that encloses the heart
- Coronary arteries: blood vessels serving the heart muscle
- Septum: a wall of tissue dividing the left and right sides of the heart
- Valve: a one-way opening that closes to prevent blood backflow, it is present at the exits of the heart and between atria and ventricles
- Atrium: an upper heart chamber (plural, atria), they receive blood from the circulation (systemic or pulmonary)
- Ventricle: a lower heart chamber, they force blood out into the circulation (systemic or pulmonary)
- Apex: bottom of the heart
- Artery: blood vessel carrying blood away from the heart
- Vein: blood vessel carrying blood to the heart
Heart Structure
The heart is made of four chambers, and blood flows through them in order: right atria, right ventricle, left atria, left ventricle. Between the right and left sides, though, the blood goes through the lungs to exchange carbon dioxide it collected in the body for oxygen it can carry to the body.
Blood enters the right atria from the venous system, and exits the left ventricle through the aorta into the arterial system. Blood flows from the atrium to the ventricle during a heart beat based on the synchronous contraction of the heart muscle (see below). Between each atrium and ventricle, there is a valve. Valves are also found where the heart and aorta, and heart and pulmonary artery meet.
- An overview of the human heart valves
- Anatomy and pathology
- Tricuspid valve - separates the right atrium and ventricle, opens when the right atrium fills with blood returning to the heart via the veins
- Pulmonary valve - separates the right side of the heart from the pulmonary circulation, forced open by the contraction of the right ventricle
- Mitral valve - separates the left atrium and ventricle, opens when the left atrium fills with blood returning to the heart from the lungs
- Aortic valve - separates the left side of the heart and the aorta, forced open by the contraction of the left ventricle
Exterior view of the heart
Coronary arteries
- Right coronary artery - serves the right atrium and right ventricle, branches into the posterior descending artery to serve the ventricular septum and left ventricle
- Left coronary artery - starts at the aorta to branch into the left circumflex and left anterior descending
- Left circumflex artery - back of the left atrium and left ventricle
- Left anterior descending artery - front left atrium, ventricles and septum
Help for studying the heart
Functional Terminology
- Contraction: the myocardium reacts to electrical impulses by squeezing, similar to contraction in skeletal muscle
- Node: a nerve fiber bundle that conducts electrical pulses in the cardiac tissue, includes sinoatrial (SA) node and atrioventricular (AV) node
- Fibrillation: an irregular heart rhythm (arrhythmia) due to unsynchronized contraction, often rapid
Circulation
- Difference between systemic and pulmonary circulation
- The function of the human circulatory system is to transport oxygen and nutrients to the tissues, but also to transport wastes to the kidneys and ...
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Comments
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shoppershunt
May 7, 2012 @ 8:39 am | delete
- i really liked the animation of electrical system. great job..
www.healthpundit.net
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mitral16 Apr 21, 2012 @ 2:09 am | delete
- Interesting perspective! And we, the patients, should be involved and take responsibility in our lifestyle choices and health care.
Heart Valve Repair
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lena
Feb 20, 2012 @ 6:42 am | delete
- Great tips, cheers to the article author. Its understandable to me now, the effectiveness and importance is mind-boggling. Thank you once again and good luck!
http://www.themitralvalve.org
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Protasker
Feb 9, 2012 @ 7:45 pm | delete
- Fascinating, heart disease run in the family, good to know.
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kiwinana71
Feb 9, 2012 @ 4:02 pm | delete
- Very interesting lens, there is so much to keeping our hearts beating, thanks for the great photos, I felt as though it was my heart I was looking at. Thanks for sharing. Blessed
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