How is the flow of blood to the organs regulated ?

In a closed circulatory system, the I. blood is found in vessels II. Arterial musculature and precapillary sphincter regulate flow of blood to the organs III. The circulating fluid baths internal organs directly. IV. The body cavity, called haemocoel is found. Choose the correct answer

The atrial systole increase the flow of blood into the ventricles by about

Describe the flow of blood through the heart of human beings.

Assertion : In open circulatory system blood is pumped by heart passes throgh large vessels into open spaces or body cavities called sinuses. Reason : This distribution of blood to different organs, is well regulated.

In which of the following organism the regulation of blood flow cannot be precisely regulated?

In which of the following organisms the regulation of blood flow cannot be precisely regulated?

How are the genes that code for enzymes regulated ?