Unit 1 Section 5: The Circulatory System Flashcards
multicellular organisms need a transport system because…
they have a low surface area to volume ratio
their cells are very deep within
Single circulatory system
blood only passes through the heart once in each complete circuit of the body. (must say in each complete circuit)
Single circulatory system example
Fish: the heart pumps blood to the gills to pick up oxygen and on to the rest of the body in a single circuit.
Double Circulatory System
blood passes through the heart twice in each complete circuit of the body. (must say in each complete circuit)
Double Circulatory System
Mammals: the right side of the heart pumps to the lungs,from the lungs it travels to the left side of the heart, which pumps it to the rest of the body.
Advantage of Double Circulatory System
the heart can give the blood an extra push between the lungs and the rest of the body, making the blood travel faster.
Pulmonary and systemic systems
Pulmonary - When the blood is pumped to the lungs and back to the heart
Systemic - When the blood is pumped round the body and back to the heart.
Closed circulatory system
blood is enclosed inside blood vessels
Closed circulatory system example
(Mammals &) Fish : Heart pumps blood to arteries, which branch into capillaries, substances diffuse into and out of the blood however the blood stays in the capillaries, veins transport the blood back to the heart.
Open circulatory system
Blood flows freely through the body cavity
Open circulatory system Example
Insects: heart is segmented, contracting in waves from the back, pumping the blood into a single main artery, the artery opens up into the body cavity, the blood flows around the organs gradually making it’s way back into the heart through a series of valves. the blood doesn’t supple the cells with oxygen, this is done via the tracheal system.
