Supply of Blood

The heart acts as a pump that normally beats about 60-100 times per minute. It pumps blood through our body and carries oxygen to all the tissues and cells of the body. The blood supplied with oxygen then returns to the heart with carbon dioxide. The heart then sends blood to the lungs to increase oxygen. This cycle is repeated several times. This is known as the circulatory system. The circulatory system is responsible for the supply of blood throughout our body. The circulatory system is also known as the cardiovascular system. There are two types of circulatory systems in the human body – systemic and pulmonary circulatory systems. 

The circulatory system

The circulatory system can be broadly divided into two types – the close circulatory system and the open circulatory system. The blood does not directly contact the tissue in the closed circulatory system. In this system, the blood pressure is high. This circulatory system is found in echinoderms, molluscs and all vertebrates. The respiratory pigments present in the blood flowing through this system are contained in red blood cells. The closed circulatory system is more efficient because blood volume can be regulated by the contraction and relaxation of the smooth muscles of blood vessels. Blood flows through the heart and a closed chamber consisting of blood vessels in the closed circulatory system. Gas and nutrients enter the interstitial fluid through the walls of the capillaries. The lymphatic system is composed of lymph capillaries, lymph and lymph vessels. It is an extension of the circulatory system.

Blood flows from large open spaces, fissures, and interstitial sinuses in an open circulatory system. In this system, the blood pressure is very low. They are found in higher invertebrates, namely shrimp, insects, etc. The supply of blood is in direct contact with the tissues. The exchange of gas and nutrients occurs directly between the tissue and the blood. Blood flow cannot be stopped because it flows through an open space. The exhaled pigment in the blood flowing through this system dissolves in plasma. There are no red blood cells involved.

How Does The Heart Supply Itself With Blood?

The blood supply begins when the heart is at ease in between heartbeats. Blood flows from the atria or the upper two chambers to the lower two chambers (ventricular), causing the heart to expand. The ventricles then pump blood into the aorta at the ejection stage. The left ventricle pumps oxygen-rich blood into the aorta of the systemic circulation. The blood goes to the larger arteries and finally to the capillary network. Blood supplies the necessary nutrients, oxygen, and other important substances to the other parts of the body. Blood also absorbs waste products, carbon dioxide and other unwanted substances from the other parts of the body to be purified by the heart. The veins collect the deoxygenated blood and send it to the right atrium and right ventricle. 

This condition marks the beginning of pulmonary circulation, where the right ventricle pumps deoxygenated blood into the pulmonary arteries. This artery branches into smaller arteries and eventually into capillaries. Capillaries form a small network surrounding the air sac called the alveoli in the lungs. Here, carbon dioxide is released from the bloodstream into the air in the alveoli. When you exhale, carbon dioxide is emitted from your body. Fresh oxygen enters the bloodstream through the alveoli when you breathe in, making the blood oxygen-rich. The blood rich in oxygen then travels from the lungs through the pulmonary veins to the heart’s left ventricle. Subsequent heartbeats lead to a new systemic cycle.

The circulatory system works with the help of blood vessels such as veins, capillaries and arteries. These blood vessels work with the lungs and heart to continuously circulate blood throughout the body.

Supply Of Blood In Kidney 

The renal arteries are an important part of the circulatory system associated with blood supply to the kidney. They carry blood from the heart’s main artery or aorta to the kidneys. About half a cup of blood flows per minute from the renal arteries through the kidneys. 

Your kidney is part of the urinary system. They filter the blood waste and excess water that your body excretes while urinating. A healthy kidney can filter up to 150 litres of blood per day. There are two renal arteries, one for the right kidney and one for the left kidney. Each renal artery enters the kidney at a point called the hilum. This area is the entrance and exit of blood vessels and nerves leading to the kidneys. 

The arteries branch into small blood vessels all over the kidney. The branches of the renal arteries include: 

• Nephrons: Blood from the renal arteries flows into a small filter in the kidney called the nephron. 

• Glomerulus: A group of small blood vessels in each nephron (glomerulus) allows waste products and water to flow into the tubules and filter impurities. Proteins and blood cells remain in the glomerulus. 

• Tubules: When the tubules remove the waste products, the blood vessels adjacent to the tubules reabsorb the filtered fluid and nutrients and minerals. The water and waste products left in the renal tubules constitute urine and are subsequently excreted from the body. 

• Renal veins: Filtered blood exits the kidneys through the renal veins and circulates throughout the body. The blood supply of the kidney diagram helps in understanding the divisions well. 

Conclusion

Our circulatory system plays an important role in keeping us alive. The blood vessels supply blood to the lungs for oxygen; the oxygenated blood is supplied to the heart. The heart then pumps the oxygen-rich blood from the arteries to the rest of the body. Symptoms such as high cholesterol, high blood pressure and atherosclerosis can affect cardiovascular health. If we have any of these conditions, talking to the doctor can help and direct us to take steps to protect our cardiovascular health.