blood vessels

Question 1

vessels going away from the heart

Answer 1

arteries, arterioles (several hundred million), capillaries (10 billion)

Question 2

vessels going toward the heart

Answer 2

capillaries, venules, veins

Question 3

layers of artery

Answer 3

tunica externa, tunica media, tunica interna

Question 4

tunica media

Answer 4

very thick, allowing arteries to resist pressure - responsible for vasodilation and vasoconstriction

Question 5

capillaries

Answer 5

everywhere blood is needed - only place gas exchange takes place, O2 and CO2 switch places by simple diffusion

Question 6

veins

Answer 6

blood tends to pool in veins - valves prevent backflow - skeletal muscle contraction and body movement help to get blood back to heart - tunica externa, media, interna

Question 7

chemoreceptor reflexes

Answer 7

in carotid arteries and aortic arch - responds to changes in carbon dioxide, oxygen, or ph

Question 8

babies

Answer 8

placenta=gas exchange - breath in amniotic fluid - umbilical cord blood goes to liver and right atrium

Question 9

foramen ovale

Answer 9

hole in heart with flap found in all babies between the atria - blood can go from right to left atria but not other way - purpose is to bypass pulmonary circuit