Introduction to cardiovascular system

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      • The cardiovascular system is the primary circulatory system of the human body.

        It comprises:
        • a heart
        • blood
        • blood vessels





      • General Functions of the Cardiovascular System
      • One function of the cardiovascular system is transport. 

        Some substances carried by the cardiovascular system are dissolved or suspended in the fluid portion of the blood. 

        Others are bound up in special cellular elements called red blood cells.

        The cardiovascular system also provides protection against foreign substances. This function involves active attack by white blood cells as well as more subtle processes of the immune system.
        • Direction of Flow of Arteries and Veins
        • Blood vessels are the conduits of the cardiovascular system. They make up a closed system, since there is no place in the system where whole blood can leave.

          Arteries generally carry blood from the chambers of the heart to the tissue of the body. 

          Veins carry blood from the tissues to the chambers of the heart. 

          (Coronary arteries carry blood from the chambers of the heart inside to the walls of the heart outside.).
          • The Circulatory System
          •                      The Circulatory System
          • Blood circulation is also a two cycle system. 

            It involves both the pulmonary cycle and the systemic cycle. Blood circulates through two circuits.

            In the pulmonary cycle, blood circulates from the heart to the lungs and back to the heart. 

            In the systemic cycle, blood circulates from the heart to the rest of the body and back to the heart.

              • Fetal Circulation

                • Since the fetus is located within the uterus, its lungs do not take in air. 

              • Therefore, the pulmonary cycle does not function in the fetus.

              • Essentially, fetal blood flows to and from the placenta. 

              • There are certain bypasses in the heart to avoid the pulmonary cycle. 

              • At the time of birth, the fetal circulation is changed to the normal pattern.



        • Blood And Energy metabolism
        • The life processes cannot continue in the body’s cells without sources of energy.

          The cardiovascular system is critical to the mobilisation of energy in the following areas: 
          • Transport of glucose and oxygen
          • Transport of hormones
          • Transport of fats
          • Prioritisation of blood supply

          • Transport of Glucose and Oxygen
          • The blood carries glucose and oxygen around the body. Energy is released from the glucose during metabolic oxidation and stored in ATP molecules. This stored energy can then be retrieved when required by the life processes of the body.









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