the circulatory system and cardiac cycle

Question 1

what is a mammal’s circulatory system an example of?

Answer 1

mass flow- there is bulk movement of substances down a pressure gradient.

Question 2

why is mass flow needed in a mammal?

Answer 2

diffusion alone would be too slow to supply the cells with enough oxygen to maintain the chemical reactions of the cell

Question 3

what kind of system is the mammalian circulatory system?

Answer 3

a closed, double circulatory system

Question 4

how is the circulatory system closed?

Answer 4

the transport medium (the blood) is contained within a network of blood vessels

this means high pressure and rapid rate of flow can be maintained

Question 5

what is the circulation to the lungs called?

Answer 5

pulmonary circulation

here deoxygenated blood is delivered to the lungs where gas exchange takes place to make the blood oxygenated

Question 6

what is the second circulation to the rest of the body called?

Answer 6

systematic circulation

here oxygenated blood is delivered to the body cells and deoxygenated blood is moved away

Question 7

why is a separate circulation to the lungs required?

Answer 7

because a lower pressure is required in the lungs to prevent accumulation of fluid in the alveoli and to allow gas exchange to occur in narrow capillaries

if there was just one circulation then the pressure drop required in the lungs would mean that there was not great enough pressure to then move oxygenated blood around body

Question 8

what is the order of the cardiac cycle?

Answer 8

diastole
atrial systole
ventricular systole