Circulation

The circulatory system acts as a transportation network for our cells and tissues

It supplies nutrients and removes wastes It is 96000 km long

Circulatory system

Blood vessels: arteries

Carry blood away form the heart to the tissues Thick artery walls withstand and maintain the

pressure generated by the heart Arteries branch into smaller arteries and eventually

become arterioles Arteriole walls are much thinner. Smooth muscle

allows them to increase/decrease in diameter depending on where blood is needed

When vessels are dilated, blood pressure is lowered

Blood vessels: capillaries

Connect arteries with veins in tissues Arterioles branch into smaller vessels called

capillaries Capillary walls are only one layer of endothelial

cells thick They are the site of diffusion into and out of the

blood Nutrients diffuse from blood to tissues Wastes diffuse from tissues to blood

Blood vessels: veins Carry blood from capillaries to the heart Once blood has traveled through capillaries it enters

venules As venules join together and get larger, they become

veins Veins are composed of three layers of tissue (like

arteries) but the middle layer is much thinner Veins can stretch easily to increase blood volume Many veins contain valves (such as in your legs and

arms) which prevent back flow Skeletal muscle contractions help move blood back

to the heart

Vascular pathways: pulmonary circuit

Carries blood to and from the lungs Composed of pulmonary arteries and pulmonary

veins

Vascular pathway: systemic circuit Carries blood to all the

bodies tissues Aorta Subclavian artery/veins

(arms) Carotid arteries (neck) Iliac artery/vein (hips) Femoral artery (leg) Coronary artery (heart)

• Jugular vein (neck)

• Mesenteric arteries and veins (intestine)

• Renal artery/vein (kidneys)

• Hepatic portal vein (small intestine to liver)

• Hepatic vein (liver to inferior vena cava)

Measuring pulse

• Radial (wrist)

• Cartodid (neck)

• Brachial (arm)

• Femoral (leg)