B7
Oxygenated/Deoxygenated blood
Humans have a double circulatory system, which is made of 2 parts:
-Pulmonary system
-Systemic system
The heart’s two upper chambers are called atria. The two lower chambers are ventricles.
They are separated by atrioventricular valves.
The left atrium receives blood from pulmonary veins, as the right one receives blood from the vena cava,
which is the blood from the rest of the body.
The blood in the left ventricle is pumped into the aorta, which takes it all around the body. In the right
ventricle it is taken by the pulmonary artery.
Left ventricle is bigger and has thicker walls because the blood pressure in it is higher than in the right
ventricle.
CHD factors are:
-Tobacco
-Diet
-Obesity
-Stress
-Genes
The three stages of heart pumping blood are:
-Relaxation: muscles relax to let the blood flow into the heart.
-Atrial contraction: muscles of the atria contract, forcing blood to enter the ventricles.
-Ventricular contraction: muscles of the ventricles contract to push the blood into the arteries.
Arteries have a small lumen, smooth lining, and a thick outer wall. They transport blood out of the heart.
Capillaries take nutrients, oxygen, and other materials to cells and take away their waste. They are very
thin, 1 cell thick.
Veins are capillaries joined up again. They keep blood flow constant, slow and smooth, and have a wide
lumen to help that. They return blood to the heart.