What is the need for a circulatory system?

Describe the events in the cardiac cycle. Explain 'double circulation'.

The state of equilibrium in the body with respect to various functions and to the chemical composition of fluids and tissues is called

Cords of Billroth are blood-filled spaces found in which of the following organs?

Given below are four statements $(i-iv)$ regarding the human blood circulatory system.
$(i)$ Arteries are thick-walled and have a narrow lumen as compared to veins.
$(ii)$ Angina is acute chest pain when the blood circulation to the heart muscle is reduced.
$(iii)$ Persons with blood group $AB$ can donate blood to any person with any blood group under the $ABO$ system.
$(iv)$ Calcium ions play a very important role in blood clotting.
Which two of the above statements are correct?

What is the study of the circulatory system called?