The Heart Where is your heart n Can

The Heart

Where is your heart n Can you locate your heart… – Why can you feel it in this location…

Fun Facts n Your heart is about the size of a large fist. n It has a mass of approximately 300 grams. n The heart is a tough muscular organ which beats about 70 times and pumps 5 litres of blood every minute. n Pumping over 7000 litres of blood each day, it has pumped about 35 million litres in your life time as a grade 11 student. Overview: https: //www. youtube. com/watch? v=H 04 d 3 r. JCLCE

The Heart n The heart is almost entirely muscle. It is composed of cardiac muscle called the myocardium. n It has 4 chambers.

Anatomy of the Heart • The heart has 2 atria (upper chambers). • Both atria have very thin walls used to collect blood returning to the heart through veins (waiting room). • The heart has 2 ventricles (lower chambers). • The ventricles have very thick muscular walls that contract forcefully, pushing blood out of the heart to the lungs and body through arteries. • Septum: Muscular central wall dividing the mammalian heart into 2 halves.

Major Veins There are 2 main veins that bring deoxygenated blood from the body to the heart: n 1) Superior Vena Cava – Veins from the head and upper body feed into the superior vena cava, which empties blood into the right atrium of the heart. n 2) Inferior Vena Cava – Veins from the legs and lower torso feed into the inferior vena cava, which empties blood into the right atrium of the heart. n

The Pericardium The heart is surrounded by a thin, tough, fluidfilled membrane called the pericardium. The pericardial fluid bathes the heart, preventing friction between its outer wall and the membrane.

Valves n n The chambers of the heart are separated by valves. Atrioventricular (AV) valves: Two valves which regulate the flow of blood between the atria and ventricles. The pressure of the blood in the atrium forces the valve open, but when pressure develops in the ventricle, the pressure pushes the flaps open against each other, effectively closing the opening. 1) Tricuspid valve: Regulates blood flow between the right atrium and right ventricle. 2) Bicuspid (mitral) valve: Allows oxygen-rich blood from your lungs to pass from the left atrium into the left ventricle.

Valves Continued Semilunar valves: Two valves which regulate the flow of blood between the ventricles and the major vessels leaving those ventricles. n 1) Pulmonary semilunar valve: Located between the right ventricle and the pulmonary artery to prevent the backflow of blood. n 2) Aortic semilunar valve: Prevents backflow into the left ventricle from the aorta when the ventricle relaxes. n

The Heart Rap: https: //www. youtube. com/watch? v=KSbb. Dnb. SEy. M

Pulmonary vs. Systemic Circuit In the pulmonary system, deoxygenated blood leaves the heart through the pulmonary trunk which branches into the left and right pulmonary arteries, goes to the lungs, and returns to the heart through the left and right pulmonary veins (with oxygenated blood). n In the systemic system, oxygenated blood leaves the heart through the aorta, goes to all the organs of the body through the systemic arteries, and then returns the deoxygenated blood to the heart through the systemic veins. n

1) Label the diagram of the heart! 2) Use two different colours to distinguish between the areas of the heart that carry oxygenated blood and the areas carrying deoxygenated blood.