Circulatory system
The body system responsible for carrying blood, nutrients, and waste
throughout the body
Cardiac
Related to the heart
The structure of an artery, a vein and a capillary
Pulmonary
Related to the lungs
.
This is known as the pulse.
In some places in the body the arteries are relatively near the surface.
In these places you can feel the bulge as blood is forced out of the
heart into the arteries followed by the return to normal shape.
Diagram of pulse points on the body
Valves prevent a backflow of blood in the veins
It is in the capillaries that the exchange of substances takes place
between the blood and the cells. The capillaries provide a massive
surface area and thin walls for easy diffusion.
Dissolved food and oxygen move out of the blood into the cells down a
concentration gradient by diffusion. Carbon dioxide and urea move out
of the cells into the blood in the same way.
Blood moves from the arteries into the capillary network and then
into the veins
The blood pumped out of the heart is carried around the body in a
75000 mile long transport network of blood vessels. There are three
main types of blood vessels
the arteries, the veins and the capillaries.
Arteries and veins of the body
Arteries
carry blood away from the heart in most arteries blood
is bright red and oxygenated stretch as the blood is forced
through them and go back into shape afterwards (have a pulse)
have thick walls to withstand the pressure of the blood
Veins
carry blood towards the heart in most veins the blood
is deep purple red and deoxygenated no pulse often
have valves to prevent backflow of blood much thinner walls
as much lower pressure
Capillaries
huge network of tiny vessels linking arteries with veins
narrow - often one red blood cell wide very thin walls
one cell thick to allow diffusion of substances into and out of the
blood
The main artery of the systemic circuit is
the aorta which branches out into other arteries, carrying blood to
different parts of the body.