circulatory system

why do multicellular organisms need a transport system?

due to low SA:V and long diffusion distance

what is the difference between open and closed circulatory systems?

• open systems allow free flow

• closed keeps blood in vessels

how many chambers does the heart have in a double circulatory system?

four

what is the advantage of a double circulatory system?

increases pressure and speed of oxygenated blood delivery

what vessels supply the heart with its own blood supply?

left and right coronary arteries

what type of vessel does an artery branch into?

arterioles

where does blood flow after passing through capillaries?

venules

what layer in blood vessels can control blood flow?

smooth muscle layer

what does the elastic layer in blood vessels allow?

allows vessels to stretch and recoil

what is the function of the endothelium layer in blood vessels?

provides a smooth surface to reduce friction

how do skeletal muscles help blood flow in veins?

by contracting muscles, compressing veins and pushing blood along

where is blood pressure highest in the circulatory system?

in the aorta after ventricular contraction

what causes fluctuations in blood pressure in arteries?

ventricular contraction and relaxation

why does blood pressure decrease as it moves through the vessels?

due to branching, increased lumen size, and friction

in terms of pressure, how does blood flow directionally?

high to low pressure