circulatory systems Flashcards
what is a single circulatory system
blood only passes through the heart once per circuit
what organisms have a single circulatory system
fish
what is a double circulatory system
blood passes through the heart twice per circuit
describe the circulatory system of fish
heart pumps blood to the gills to pick up oxygen and then to the rest of the body to deliver oxygen
describe the circulatory system of humans
the right side of the heart pumps blood towards the lungs to pick up oxygen
from the lungs it travels to the left side of the heart which pumps it around the body
when blood returns to the heart it enters at the right side again
what is an advantage of the mammalian system compared to the fish
gives the blood an extra blood so oxygen is delievered more rapidly
what is a closed system
blood is enclosed within blood vessels
who has a closed system
all vertebrates such as fish and mammals
describe a closed system
heart pumps blood into arteries which branch out into many capillaries
substances such as oxygen diffuse from the blood in the capillaries into body cells
veins take the blood back to the heart
what is an open system
blood isnt enclosed in vessels all the time
who has an open system
some invertebrates (insects)
describe an open system
the heart is segmented and contracts in a wave starting from the back pumping blood into one single main artery
artery opens up into the body cavity
blood flows through the organs gradually returning to the heart via valves
