Summary The circulatory system

Circulatory system
Blood vessels

Arteries
 Carries blood at high
pressure away from the
heart
 Stretch to allow blood
and then returns back to
normal (pulse)
 Carries oxygenated
blood (* pulmonary
artery)
 Divides into arterioles

Vein
 Carries blood at lower
pressure towards the
heart
 Have semi- lunar valves which prevent blood flowing backwards (because on
little/no pressure)
 Carries deoxygenated blood (* pulmonary vein)

Capillary
 Arteries >> arterioles >> capillaries
 Liquid part of blood (plasma and leukocytes) leak out and bathe cells = tissue
fluid
 Walls of capillaries thin and have pores  allows for interchange of
substances
 Capillary bed = capillaries that come from arteriole
 Capillaries unite at venues which lead to veins

, Heart

 NB// mirror image
 Closed system of tubes (red blood cells cant leave)

Right side

 Responsible for Circulation of deoxygenated blood
 Right atrium = thin walled and receives deoxy blood from
 Superior vena cava
 Inferior vena cava
 Coronary vein
 Right atrium to right ventricle via tricuspid valve (three flaps attached by
heart tendons to the inner wall of ventricle) : (valve allows for blood to flow
only 1 way)
 Right ventricle to lungs via pulmonary artery (allows to be oxygenated)
 Base or pulmonary artery = semi lunar valve (blood can only flow 1 way)


Left side