Blood Vessels

Blood Vessels

• Blood travels throughout the body in a series of blood vessels; Arteries, Capillaries, and Veins that each perform a specific function.

Capillaries

Capillaries

Capillaries Capillaries

ArteryArtery

VeinVein

Arteries – Pipelines from the Heart• Carry blood away from the heart.• Main transporters of oxygenated blood.• Have very thick walls of stiff connective tissue

and smooth muscle.– Because of the pressure the heart needs to beat

and send blood throughout the body.– Very elastic allowing them to expand.

Arteries

Capillaries – Unseen Pipelines• The smallest blood vessels• Connect arteries and veins.• Only one cell thick – “Swiss Cheese”– Site of exchange between blood and cells.• Diffusion of oxygen and nutrients into the cells.• Diffusion of carbon dioxide and wastes away from the

cells.

Capillaries

Veins – Pipelines to the Heart

• Carry deoxygenated blood back to the heart.– High in carbon dioxide and waste products.

• Thin walls of connective tissue and smooth muscle.

• Contain one-way valves to keep blood from flowing backward.– Contractions of skeletal muscles move the blood

inside the veins.

Veins

vein

vein

Blood Pressure

• Blood pressure is the force of your blood pushing against the walls of your arteries. – The force is strongest when your heart contracts

and weakest when your heart relaxes. • Two locations you can feel your pulse at:– Your neck– Your wrist

Blood Pressure

• Blood pressure is read as two numbers:– Systolic pressure – the pressure on the artery

when the ventricles contract.– Diastolic pressure – Pressure on the artery when

the ventricles relax.• Normal blood pressure would be 120 over 80.

Systemic Blood Pressure Readings

Chart Questions:

• Where is the blood pressure reading the strongest?

• Is this person’s blood pressure normal? – What’s the systolic reading?– What’s the diastolic reading?

• Where is the blood pressure the weakest?

Arteries

12080

Veins

Yes