Circulatory

Contains valves- prevent the back flow of blood Wide lumen Relatively thin walls with less muscle and elastic tissue Carries at a lower pressure

No valves Narrow lumen - maintain high blood pressure Thick walls made of muscle and elastic tissue to prevent bursting Carries higher blood pressure Usually carries oxygenated blood (except pulmonary artery)

Made of single layers of cells • to allow substance to passs easily from the blood into the body cell Lumen small - only big enough to let one red blood cell through at a time

The right atrium

On the left atrium

The strip and ventricular muscle is relaxed The blood enters the atria through vena cava and pulmonary vein Pressure increases in the atria

The serial muscular walls contract, increasing the pressure further. —> atriovencular valves to open and the blood to flow into the ventricle The ventricle walls are relaxed

After short delay the ventricular muscle walls contract - increasing pressure beyond of the atria Atrioventrcicular calve close and seminar valve open The blood is pushed out into the arteries (aorta and pulmonary arteries)

Closes at the left side of he heart

Closes at the left side of the heart

Technology used to investigate the rhythm of the heart by producing a record of electrical activity of the heart

A specialised group of cells in the right atrium with the fastest natural intrinsic rhythm it generates a regular electrical signal and act as the heart own natural pace maker to keep the heart beating regularly

A group of cells stimulated by the wave of excitement from SAN and Atria it impose a delay before transmitting. The impulse to the bundle of his • slight delay is before the AVN stimualte the bundle of his makes sure that the atria have stopped contracting before the ventricle starts

A group of conducting fibers in the septum of the heart

Conducting fibre that penetrates down through the septum of the heart spreading between and around the ventricle This ventricle contract starts at the bottom of the ventricle so that the blood is squeezed upwards toward the main arteries

Atrial contraction

Ventricular contraction

Ventricular relaxation

Contain haemoglobin Transport of oxygen No nucleus —> more space for haemoglobin Biconcave disk —> large SA:V ratio

Lymphocytes : production of antibodies Phagocytes : involved in phagocytosis

Involved in blood clotting • prevent entry of pathogens • minimise blood loss

1) platelets stick to the sit to damage 2) chemical signal are released from the platelet to attract nearby cells and clump them together 3) thromboplastin catalyse the conversion of inactive prothrombin to active thrombin 4) thrombin then catalyse the conversion of solute fibrinogen to insoluble fibrinogen 5) thrombin then catalyse the conversion of soluble fibrinogen to insoluble fibrinogen 6) forming a mesh which traps RBCs and creates a scab