What are the functions of the circulatory system?

• The circulatory system carries oxygen and nutrients between the central organs like the lungs, liver, and tissues. It also carries waste products like carbon dioxide and nitrogen compounds to the lungs and kidneys for disposal. 
• We evolved in the sea. As a result, our cells require a similar environment to function best. This is maintained by a balance of electrolytes, water, and body heat. The circulatory system, in collaboration with the drainage or lymphatic system, takes care of this. 
• Our immune system components are manufactured centrally in our liver, lymphatic tissues, and bone marrow. In addition, the circulatory system carries these to different areas for both proactive and reactive defence. 
• The circulatory system also helps control body heat and keep it uniform. For example, when the weather outside is cold, our blood vessels in the limbs contract and help regulate the loss of body heat. 
• Hormones secreted by central glands regulate our body functions. The circulatory system enables these hormones to exert their function by carrying them to the target areas. 

What are the components of the circulatory system?

• Blood circulatory system:

The circulatory system carries blood between the lungs and various tissues through the heart and a vast network of arteries, arterioles, capillaries, venules, and veins. Blood contains Red Blood Cells (RBCs) which help transport oxygen and carbon dioxide. Other cells called White Blood Cells (WBCs) are immune cells and come in different varieties, serving different immune functions. Blood also has platelets. Platelets help clotting prevent leakage and blood loss from an injury. You can read more about how the blood circulatory system functions here and how the heart pumps blood here. 

• Lymphatic system:

The lymphatic system serves as a network of drains, bringing back fluid leaked into the extracellular spaces to the blood circulatory system. It also checks foreign substances and potential cancers and infections through deep integration with the immune system in areas known as nodes. 

How big is the circulatory system?

Imagine a pipeline network spanning over 1,00,000 km with a throughput of 7200 litres of fluid daily. That is your circulatory system!

What are the common conditions that affect the circulatory system?

• Aneurysms - When the wall of an artery (which carries blood at higher pressures) gets weaker, the blood pressure acts against it and causes it to bulge out, similar to how you find blisters on your vehicle’s tires when the walls weaken. The weak spot risks having a tear, which could be life-threatening. The most common ones occur in the aorta or the brain, although they may occur in any artery.
• High blood pressure - High pressure in the blood vessels may occur for various reasons. Over time, the pressure starts affecting the walls of your arteries, which begin to lose elasticity. This affects circulation and puts more pressure on the heart, affecting it negatively.
• Plaque deposits - High cholesterol and high inflammation (reactivity) due to uncontrolled diabetes can lead to small deposits forming in the inside walls of the arteries. This is known as atherosclerosis. It increases the chances of blood clots that cause strokes and heart attacks and leads to conditions like Peripheral Artery Disease and Kidney disease. 
• Venous disease - Venous diseases like varicose veins and venous insufficiency occur when the veins cannot return all the blood it receives back to the heart. Since getting blood to flow upwards is most difficult, these conditions usually affect the lower half of the body. For example, a blood clot called deep vein thrombosis in the legs can lead to severe life-threatening conditions. 

How can you take care of your circulatory system better?

• Maintain an active lifestyle
• Exercise regularly with enough intensity for your body
• Sleep well - Lack of sleep raises your BP
• Eat good fats and maintain a balanced diet, not heavy on fats
• Eat less sugar and keep sugar levels and diabetes under check
• Find mental peace and work on your anxieties
• Maintain a healthy weight
• Do regular checkups and keep a tab of critical values like lipids and sugar levels.
• Quit smoking and drinking