Blood Vessels Circulatory System Blood vessels are organs

Blood Vessels Circulatory System

Blood vessels are organs that carry the blood throughout your body.

Blood Vessels • Did you know that your blood circulates through about 90, 000 kilometres of blood vessels in your body? • A kilometre is 1, 000 meters or 0. 621 miles!

There are three types of blood vessels: arteries, capillaries, and veins.

Arteries • Arteries are blood vessels that carry blood away from the heart. • With the exception of the pulmonary artery, they carry oxygen rich blood.

Arteries • Each time the heart contracts (squeezes), blood is pumped out at high pressure. • Arteries are thick, strong, and made of three layers of tissue that help them withstand that pressure.

Artery Arteries = Away

Veins • Veins are blood vessels that carry blood towards the heart. • With the exception of the pulmonary veins, they carry oxygen poor blood. • Veins are aided in pushing blood back toward the heart by the skeletal muscles, as they contract and squeeze nearby veins.

Veins • Like arteries, veins have three tissue layers. But veins have thinner walls because they do not receive blood directly from the heart. • The largest veins have one way valves to prevent backflow and keep blood flowing toward the heart.

Vein VEINS have VALVES and VENTURE back!

The importance of valves … Varicose Veins

Capillaries • Capillaries are the smallest blood vessels where the exchange of materials with cells (through the process of diffusion) takes place. • They form a net likestructure throughout your tissues.

Capillaries • Capillary walls are only one cell thick and may be so narrow that blood cells must pass through in single file. • Oxygen and other materials diffuse through capillary walls into the tissues and then into cells.

The Flow of Blood • Each heart beat pushes about 90 millilitres of oxygenated blood from the heart into the aorta, the body's largest artery. • From there, the blood flows to smaller arteries and then capillaries. • Eventually, it transfers its oxygen to body cells and returns back to the heart through the veins.

Blood Pressure • Contractions of the heart generate blood pressure. • Blood pressure keeps the blood flowing in the right direction. • Valves in the veins prevent the back flowof blood.

Blood Pressure • Blood pressure is a measure of the force of blood pushing against the walls of the arteries. • It is measured in millimetres of mercury (mm Hg). • Normal adult blood pressure is around 120/80 mm Hg.

Heartbeat The rhythmic change in blood pressure is called a pulse.

Sphygmomanometer (sphyg· mom· a· nom· e· ter) The tool used to measure blood pressure.

Sphygmomanometer • The cuff is pumped up with air to restrict blood flow in the arm. • As the pressure in the cuff is released, blood starts flowing again. • You can hear the flow of your blood in a stethoscope.

Helpful Videos • Ted Ed: How Blood Vessels Work https: //www. youtube. com/watch? v=Ab 9 OZs. DECZw • Types of Blood Vessels https: //www. youtube. com/watch? v=Cj. N Kb. L_-cw. A

Helpful Videos • Crash Course: Blood Vessels, Part 1 https: //www. youtube. com/watch? v=v 43 ej 5 l. Ce. Bo • Crash Course: Blood Vessels, Part 2 https: //www. youtube. com/watch? v=ZVkl Pw. GALp. I