Dejan TkalecMentor: A. Žmegač Horvat

Blood vessels

What are blood vessels?intricate networks

of tubes that transport blood throughout the entire body

Types of vessels:ArteriesVeinsCapillariesSinusoids

ArteriesTransport blood away

from the heartCarry oxygenated

blood Have relatively narrow

lumensHave relatively more

muscle/elastic tissueTransport blood under

higher pressure Do not have valves

(except for the semi-lunar valves of the pulmonary artery and the aorta)

VeinsTransport blood

towards the heartCarry de-oxygenated

bloodHave relatively wide

lumens Have relatively less

muscle/elastic tissueTransport blood under

lower pressureHave valves

throughout the main veins of the body (except venae cavae)

HistologyArteries and veins have the same structure:1.Tunica intima: single layer of simple

squamous endothelial cells, surrounded by a thin layer of elastic bands – internal elastic lamina

2.Tunica media (thickest layer): circularly arranged elastic fibers, connective tissue, polysaccharide substances surrounded by external elastic lamina; rich in vascular smooth muscle (especially in arteries)

3.Tunica adventitia: entirely made of connective tissue; contains nerves that supply the vessel

Functions Transporting blood away from the heart Transporting oxygenated blood across the body Transporting blood from arteries to capillaries Draining blood from capillaries into veins and

exchanging oxygen, carbon dioxide, water and salt between the body and surrounding tissues

Arterioles - main regulators of blood pressure and flow

Capillaries - assist in supplying body tissues with necessary components of blood

Common problemsAneurysm - weak spot in the wall of an

artery Atherosclerosis - narrowing of the

arteries caused by plaque deposits Heart disease - lack of blood supply to the

heart because of narrowed arteriesHigh blood pressure - can be caused by

obesity, diabetes, rich salt diet, smoking, high cholesterol, kidney disease...

Varicose veins - problems with valves that stop blood from running backwards

Aorta Largest artery in the body, originating from

the left ventricle of the heart and extending down to the abdomen, where it branches off into two common iliacs

Usually divided into 5 segments: 1.Ascending aorta2.Arch of aorta3.Descending aorta4.Thoracic aorta5.Abdominal aorta

Other major arteries

References http://biology.about.com/library/organs/

heart/blblood.htmhttp://en.wikipedia.org/wiki/Blood_vesselhttp://www.ivy-rose.co.uk/HumanBody/

Blood/Blood_Vessels.phphttp://www.ehow.com/

about_5110377_functions-blood-vessel.htmlhttp://video.about.com/heartdisease/How-

the-Heart-Functions.htm