Blood Vessels Flashcards
What is the vascular tree
Closed system of vessels
What do arteries do
Carry blood away from heart to tissues
What are arterioles
Smaller branches of arteries
What are capillaries
Smaller branches of arterioles. Smallest vessels
What are venules
Formed when capillaries rejoin. Return blood to heart
What are veins
Formed when venules merge. Return blood to heart
Systemic circulation
provides the functional blood supply to all body tissue. It carries oxygen and nutrients to the cells and picks up carbon dioxide and waste products. Systemic circulation carries oxygenated blood from the left ventricle, through the arteries, to the capillaries in the tissues of the body.
Pulmonary circulation
is the system of transportation that shunts de-oxygenated blood from the heart to the lungs to be re-saturated with oxygen before being dispersed into the systemic circulation.
Arteries carry blood ……
Away from heat
Veins carry blood …..
Back to heart
Special features of arteries
Thick, highly elastic walls, large radii
Special features of arterioles
Highly muscular, well innervated walls, small radii
Special features of capillaries
Thin walls, large total cross sectional area
Special features of veins
Thin walls compared to arteries, highly distension, large radii
How many layers/tunics of artery’s and veins
Tunica intima
Tunica media
Tunica adventita
Tunica intima
Inter most, includes endothelium squamous cells
Tunica media
Middle, mainly circular smooth muscle and elastin
Tunica addventita
Outer, Fibrous connective tissue, rich in collagen and elastin
Arteries serve as ….
Rapid transit pathways for blood from heat to organs. Their large radius offer little resistance to blood flow
What do arteries also act as
Act as pressure reservoir to provide driving force for
blood when heart is relaxing
- Due to elastic nature of arterial walls
What do collagen fibres provide
Tensile strength
What do elastin fibres provide
Elasticity to arterial walls
What is blood pressure
Force exerted by blood against a vessel wall
Wh at does blood pressure depend on
Volume of blood contained within vessel
Compliance of vessel walls
What is systolic pressure
Peak pressure exerted by ejected blood against vessel wall during cardiac systole
Averages 120mm Hg
What is diastolic pressure
Minimum pressure in arteries when blood is draining off into vessels downstream
Averages 80mm Hg
What can blood pressure be measured by
Indirectly with sphygmomanometer
What are korotkoff sounds
Sounds heard when determing blood pressure. Distinct from heart sounds associated with valve closure
What is pulse pressure and example
Pressure difference between systolic and diastolic pressure
If BP is 120/80, the pulse pressure is 40mm Hg (12-80)
What is mean arterial presure
Average pressure driving blood forward into tissues throughout cardiac cycle
Formula for approving mean arterial pressure
Diastolic presure + 1/3 pulse pressure
