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The Human Heart

The human heart, approximately the size of a closed fist and weighing around 300g, consists of four chambers separated by the septum, which prevents blood mixing. Valves within the heart ensure unidirectional blood flow and maintain pressure, while coronary arteries supply the heart muscle with oxygenated blood. Proper function of these structures is crucial to prevent conditions like angina or heart attacks.

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10 views3 pages

The Human Heart

The human heart, approximately the size of a closed fist and weighing around 300g, consists of four chambers separated by the septum, which prevents blood mixing. Valves within the heart ensure unidirectional blood flow and maintain pressure, while coronary arteries supply the heart muscle with oxygenated blood. Proper function of these structures is crucial to prevent conditions like angina or heart attacks.

Uploaded by

fatima
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as PDF, TXT or read online on Scribd
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The Human Heart

Mammalian Heart Structure

Heart structure

• The human heart has a mass of around 300g and is roughly the size of a closed fist

• The heart is a hollow, muscular organ located in the chest cavity

• It is protected in the chest cavity by the pericardium, a tough and fibrous sac

The human heart has four chambers and is separated into two halves by the septum

• The heart is divided into four chambers. The two top chambers are atria and the bottom
two chambers are ventricles
• The left and right sides of the heart are separated by a wall of muscular tissue, called
the septum. The portion of the septum which separates the left and right atria is called
the interatrial septum, while the portion of the septum which separates the left and
right ventricles is called the interventricular septum

• The septum is very important for ensuring blood doesn’t mix between the left and right
sides of the heart

Valves in the heart

• Valves in the heart:

o Open when the pressure of blood behind them is greater than the pressure in
front of them

o Close when the pressure of blood in front of them is greater than the pressure
behind them

• Valves are important for keeping blood flowing forward in the right direction and
stopping it flowing backwards. They are also important for maintaining the correct
pressure in the chambers of the heart

• The right atrium and right ventricle are separated by the atrioventricular valve, which is
otherwise known as the tricuspid valve

• The right ventricle and the pulmonary artery are separated by the pulmonary valve

• The left atrium and left ventricle are separated by the mitral valve, which is otherwise
known as the bicuspid valve

• The left ventricle and aorta are separated by the aortic valve

• There are two blood vessels bringing blood to the heart; the vena cava and pulmonary
vein

• There are two blood vessels taking blood away from the heart; the pulmonary
artery and aorta

Coronary arteries

• The heart is a muscle and so requires its own blood supply for aerobic respiration

• The heart receives blood through arteries on its surface, called coronary arteries

• It’s important that these arteries remain clear of plaques, as this could lead to angina or
a heart attack (myocardial infarction)
The coronary arteries cover the outside of the heart, supplying it with oxygenated blood

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