The Features, Structures and Functions of the Heart

Receives deoxygenated blood returning to the heart from the vena cava and pumps it to the right ventricle. Left atrium: Receives oxygenated blood returning to the heart from the pulmonary veins and pumps it to the left ventricle. Ventricles thicker walls (than atria), the left is thicker than the right as blood must be pumped all around the body tendinous chords papillary muscles interventricular septum (separates ventricles) Right ventricle: Receives deoxygenated blood from the right atrium and pumps it to the pulmonary artery in which it is transported to the lungs.

Left ventricle: Receives oxygen-rich blood from the left atrium and pumps it to the aorta which distributes it around the rest of the body. Atrioventricular valves anchored to the walls by chord tendinae composed of endocardium (epithelial) and connective tissue flap-like structures located between the atria and ventricles Keeps the valves from prolapsing into the atria when they close and prevents back flow of blood as it is pumped from the atria to the ventricles physiological differences between children adults.

Tendinous cords cord-like tendons 80% collagen (structural protein) and 20% elastin and endothelial cells Connects the papillary muscles to the tricuspid valve and the mitral valve in the heart. Close and open the valves and make sure they do not collapse into the atria. Septum thick and muscular upper section is thinner and more fibrous slanted backwards and to the right and curves to fit the oval shape of the ventricle Separates the left ventricle from the right ventricle to prevent oxygenated and deoxygenated blood from mixing.

Semilunar valves consists of three crescent shaped cusps (flaps of tissue) do not have tendinous chords Prevents blood flowing back intro the ventricles after contraction, links the ventricles to the pulmonary artery and aorta. Aorta a tube about a foot long and just over an inch in diameter largest artery in the human body composed of three layers containing connective tissues and elastic fibres Supplies oxygen-rich blood from the heart to the rest of the body. The fibres allow the aorta to stretch to prevent over-expansion from the pressure that is exerted on the walls by blood flow. Vena Cava two large veins (superior and inferior vena cava).

Carries deoxygenated blood from various regions of the body to the right atrium of the heart. Superior vena cava transports blood from the head, neck, arm and chest regions of the body to the right atrium. Inferior vena cava brings blood from the lower body regions (legs, back, abdomen and pelvis) to the right atrium. Pulmonary vein there are four, two from each lung wide with very little elastic or muscular tissue contains valves to prevent back flow of blood large lumen thin muscular wall (endothelium) Receives oxygenated blood from the lungs and drains it into the left atrium of the heart.

 Pulmonary artery begins at the base of the right ventricle short and wide (approx 5cm in length and 3 cm in diameter) Carries deoxygenated blood from the right ventricle in the heart to the lungs. Divided into the left and right pulmonary arteries. The blood it carries is then enriched with oxygen and resent to the left ventricle from where it is distributed. Coronary arteries first blood vessels that branch off from the aorta run along the outside of the heart and have small branches that dive into the heart muscle to bring it blood can dilate to increase blood flow Supplies blood to the atria, ventricles and septum of the heart.