The Circulatory System Parts and Function
The 3 main parts of the Circulatory System The Heart The Blood Vessels Blood
THE HEART
Parts of The Heart The Atria -Receiving Chambers The Ventricles -Pumping Chambers The Valves -Controls Flow The Septum -Divides the Heart
Cardiac Cycle Systole – contraction of heart muscle Diastole – relaxation of heart muscle
Heart sounds (lub-dup) are associated with closing of heart valves. First sound occurs as AV valves close and signifies the beginning of systole. Second sound occurs when SL (semilunar) valves close at the beginning of ventricular diastole.
Blood Vessels
Types of Blood Vessels Arteries -Carry blood away from the Heart -The Aorta is the largest artery Veins -Carry blood to the Heart -Veins contain valves -The Vena Cava is the largest vein Capillaries -Known as the “Distribution Pipes”
Blood
Blood accounts for 8% of body weight. Its volume in healthy adult males is 5-6 liters. The blood has many functions: transports nutrients to cells throughout body delivers oxygen, removes carbon dioxide carries hormones protecting the body from infection
The Composition of Blood The Plasma (Fluid) makes up 55% of the blood volume. The Solids (Cells) make up 45% of the blood volume.
Blood Plasma 97% Water Other 3% -Antibodies and Proteins - Nutrients and Wastes
Blood Solids Red Blood Cells -Carry oxygen -Contain Hemoglobin White Blood Cells -Attack bacteria & other invaders Platelets -Control the blood clotting process