Blood vessels
Dejan Tkalec
Mentor: A. Žmegač Horvat
What are blood vessels?
 intricate networks of tubes
that transport blood
throughout the entire body
Types of vessels:
 Arteries
 Veins
 Capillaries
 Sinusoids
Arteries
Veins
 Transport blood away from
 Transport blood towards the






the heart
Carry oxygenated blood
Have relatively narrow
lumens
Have relatively more
muscle/elastic tissue
Transport blood under higher
pressure
Do not have valves (except
for the semi-lunar valves of
the pulmonary artery and the
aorta)




heart
Carry de-oxygenated blood
Have relatively wide lumens
Have relatively less
muscle/elastic tissue
Transport blood under lower
pressure
Have valves throughout the
main veins of the body
(except venae cavae)
Histology
 Arteries 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 problems
 Aneurysm - 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 arteries
 High 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 aorta
2. Arch of aorta
3. Descending aorta
4. Thoracic aorta
5. Abdominal aorta
Other major arteries
References
 http://biology.about.com/library/organs/heart/blblood.htm
 http://en.wikipedia.org/wiki/Blood_vessel
 http://www.ivy-
rose.co.uk/HumanBody/Blood/Blood_Vessels.php
 http://www.ehow.com/about_5110377_functions-bloodvessel.html
 http://video.about.com/heartdisease/How-the-HeartFunctions.htm