The Blood Vessels

Roadways of the Body

What do Blood Vessels Do?

• Carry Blood!• Exchange nutrients, wastes, and

gases with tissues• Transport• Help maintain blood pressure• Direct blood flow to tissues (when

increased or decreased blood flow is required)

Three types of blood vessels

• Arteries• Veins• Capillaries

Three major parts of blood vessels:

• Tunica Intima:• The innermost layer; consists of

simple squamous epithelium• Tunica Media:• The middle layer; consists of smooth

muscle and elastic and collagen fibers

• Tunica Adventia:• The outermost layer; consists of

connective tissue

Arteries:

• Thick muscular walls• Blood moving under high pressure

and speed• Blood is oxygenated (except

pulmonary arteries)• Always take blood away from the

heart• Branch into arterioles• Arterioles branch into capillaries

Capillaries:• Consist of a single layer of

endothelium only one cell thick• The site of nutrient, waste, and gas

exchange between the blood and the body cells

Veins:

• Capillaries flow into venules• Venules flow into veins• Veins have thinner walls• Blood moves under lower pressure

and slower speed• Veins need valves to keep blood

moving in the correct direction• Always take blood to the heart• Carry deoxygenated blood (except

the pulmonary veins)

Heart Vessels:

1. Right common carotid artery2. Right internal jugular vein3. Right subclavian artery4. Brachiocephalic artery5. Brachiocepahlic vein6. Superior vena cava7. Left common carotid artery8. Left internal jugular vein9. Left subclavian artery10.Aortic arch

Major Arteries:

1. Brachial2. Ascending aorta3. Subclavian4. Common carotid5. Brachiocephalic6. Descending aorta7. Coronary8. Abdominal aorta9. Common illiac10. femoral

Major Veins:

1. Brachial2. Brachiocephalic3. Jugular4. Subclavian5. Superior vena cava6. Coronary7. Inferior vena cava8. Iliac9. Femoral10. Great saphenous