The Cardiovascular System

Transports blood, oxygen and nutrients to the body

Consists of the heart, blood and blood vessels

Blood: four main components: RBC, WBC, platelets, plasma

Haemoglobin: the pigment that binds oxygen for transport in the blood

Red blood cells: erythrocytes

carries oxygen, nutrients, waste

White blood cells: leucocytes

Fights diseases and protects the body from infection

Platelets: thrombocytes

Gather at the site of injury and help the clotting process

Plasma: mixture of water and dissolved substances (protein, electrolytes, nutrients)

 

Blood Vessels

Artery:

Thickest wall

Can withstand the high pressure created by the heart

Carries blood away from the heart

Capillary:

Thinnest wall

Site of exchange

Form extensive branching network through tissues

Vein:

Less muscular and stretchy

Blood moves through at a lower pressure

Special valve to help flow blood only one way

Carries blood towards the heart

 

The Heart

Atria: receives blood

Ventricles: eject blood from the heart

Septum: divides heart into left and right

R: receives deoxygenated blood

  1. Right atrium receives deoxygenated blood through the vena cava

  2. Deoxygenated blood moves through the right atrium

  3. Blood moves through the tricuspid valve into the right ventricle

  4. Blood moves from the right ventricle to the pulmonary artery through the pulmonary valve

  5. Blood is then pumped to the lungs via the pulmonary artery

L: receives oxygenated blood

  1. Left atrium receives oxygenated blood through the pulmonary vein

  2. Oxygenated blood moves through the left atrium

  3. Blood moves through the mitral/bicuspid valve into the left ventricle

  4. Blood moves from the left ventricle to the aorta through the aortic valve

  5. Blood is then pumped to the body via the aorta

 

Pulmonary Circuit

  • deoxygenated blood from the body, to the lungs

  • The right atrium takes in deoxygenated blood from the superior and inferior vena cava

  • Blood is pumped down into the right ventricle and taken to the lungs through the pulmonary artery where oxygen replaces carbon dioxide

  • Blood becomes oxygenated

 

Systemic Circuit

  • Oxygenated blood to the body

  • Oxygen carrying blood from the lungs enters the left atrium through the pulmonary veins

  • Blood is pumped into the left ventricle and is sent to the body through the aorta

 

The cardiac cycle

Begins with an impulse initiated by the SA node

The left and right side work together simultaneously

Each atrium receives blood from a vein pushing it into their own respective ventricles

The blood is then pumped out of the heart through an artery

The blood is then sent to the body or to the lungs

The cardiac cycle doesn't require a nerve stimulation to make the heart muscle contract

Myogenic contraction: the heart contracts by itself