lesson 14 - circulatory system

what is the purpose of the circulatory system?

transportation, regulation, and protection

what is in plasma?

water

what does plasma help?

circulate formed elements

what are erythrocytes made of?

hemoglobin

what do erythrocytes help with?

oxygen transportation

what do leukocytes help with?

defense against foreign invaders

what are platelets?

cell fragments

what do platelets do?

they are sticky so they can form clots

what do arteries do?

carry oxygenated blood away from the heart

how many tissue layers are veins and arteries made up of?

four

why do arteries have a thicker smooth muscle layer?

they need to stretch since they pump blood

when muscles contract what happens to venous valves?

the pressure opens the valves

when water solutes in blood plasma what happens?

it gets filtered through capillary walls

what is the result of the filtration of water soluted in blood plasma?

lymph

why can’t proteins pass through capillaries?

too big

what happens to excess tissue fluid?

it drains into lymph capillaries