Start your hassle free Education Franchisee and grow your business!

Know more
Contact Us
Need assistance? Contact us on below numbers

For Study plan details

10:00 AM to 7:00 PM IST all days.

For Franchisee Enquiry


Join NOW to get access to exclusive
study material for best results

Thanks, You will receive a call shortly.
Your cart is empty

NEET Biology Body Fluids and Circulation

Body Fluids and Circulation PDF Notes, Important Questions and Synopsis




  • Blood is a fluid connective tissue made of plasma and cellular elements. 


    Cellular elements




    Clotting factors











  • According to the ABO blood group system, there are four blood groups—A, B, AB and O. O type of blood is called a universal donor, and AB type of blood is called a universal recipient.

  • Lymph is a tissue fluid which supplies oxygen and nutrients and also has a role in the defence mechanism

  • Hearts in Vertebrates


    Amphibians & Reptiles


    • Two-chambered heart
    •  Three-chambered heart
    •  Four-chambered heart
    •  One atrium, one ventricle
    •  Two atria, one ventricle
    •  Two atria, two ventricles
  • Cardiac Cycle
    • The series of events which occur during one complete beat of the heart is called a cardiac cycle.

    • Contraction is also known as systole, while relaxation is known as diastole.

    • The duration of one cardiac cycle is 0.8 seconds.



Atrial Systole and Ventricular Diastole

  • The SA node generates an action potential which stimulates the atria to undergo contraction.

  • With the onset of the atrial systole, the ventricles undergo diastole.

  • The semilunar valves close; while the tricuspid and bicuspid valves open, blood enters the respective ventricles.

Ventricular Systole and Atrial Diastole

  • With the onset of the atrial diastole, the ventricles undergo systole.

  • The tricuspid and bicuspid valves close, preventing the backflow of blood into the respective atria.

  • Both semilunar valves open, and the ventricular blood enters the pulmonary artery from the right ventricle and the aorta from the left ventricle.

 Joint Diastole

  • It is also called general pause.

  • It lasts for 0.4 seconds.

  • Both atria and ventricles are in the relaxed state.

  • The left atrium receives blood from the lungs via four pulmonary veins, and the right atrium receives blood from the superior and inferior vena cavae.

  • Some amount of blood also enters the respective ventricles.

  • Pulmonary and aortic semilunar valves close to prevent the backflow of blood into the ventricles.


  • During each cardiac cycle, approximately 70 ml of blood is pumped out of each ventricle which is called the stroke volume.

  • ECG or electrocardiogram is the graphical representation of the electrical activity of the heart during a cardiac cycle.

  • The instrument used to obtain ECG is called an electrocardiograph.

  • Double circulation means blood passes through the heart twice.
    • Pulmonary circulation
    • Systemic circulation  

  • The hepatic portal system connects the digestive tract and the liver. The hepatic portal vein carries blood from the small intestine to the liver before it is sent into the systemic circulation.

  • The coronary system of blood vessels takes care of the circulation of blood to the cardiac wall of the heart.