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Blood Circulation

The movement of blood throughout the body is referred to as blood circulation. The heart and blood vessels are a part of the circulatory system. It is sometimes referred to as the cardiovascular system, where cardio refers to the heart and vascular refers to blood vessels. The circulatory system distributes oxygen, nutrients, and hormones to the body's muscular tissue and organ systems.

Additionally, the circulatory system aids in the body's chemical and waste elimination. Blood is circulated throughout the body by the heart through a system of arteries and veins known as blood vessels.

Parts of the Circulatory System

The parts included in the circulatory system are as follows:

  1. Heart is a muscular organ that circulates blood throughout the body.
  2. Blood Vessels include arteries, veins, and blood capillaries.
  3. Blood is a mixture of red blood cells, white blood cells, plasma, and blood platelets.

Important Functions of the Circulatory System

The circulatory system's primary function is to transport blood throughout the body. Organs, muscles, and tissues function to support human survival. The circulatory system facilitates the body's waste-removal process. Among these wastes are:

  1. Carbon dioxide is produced by respiration.
  2. Various chemical waste and by-products from the organs.
  3. Debris from the food and beverages people consume.

Working of the Circulatory System

The circulatory system's primary objective is to distribute blood throughout the body using blood vessels such as arteries, veins, and capillaries. The blood vessels circulate blood to the whole body in cooperation with the heart and lungs.

Blood Circulation

It includes the following steps:

  1. The right ventricle, or bottom right pumping compartment of the heart, sends deoxygenated blood to the lungs. The blood then passes through the pulmonary trunk, which is linked to the main pulmonary artery.
  2. The blood cells absorb oxygen.
  3. The oxygenated blood is transported from the lungs through the pulmonary veins to the left atrium, the uppermost heart chamber.
  4. The oxygenated blood is then sent into the lower chamber by the upper section called the left ventricle. This segment of the heart distributes blood throughout the body via arteries.
  5. Blood collects and excretes nutrients, hormones, and by-products as it flows through the body's organs.
  6. Veins carry carbon dioxide and deoxygenated blood away from the body before returning it to the heart, which pumps it back to the lungs.
  7. Whenever individuals exhale, the lungs eliminate CO2 (carbon dioxide).

Types of Circulatory Systems

There are three circuits in your circulatory system. Blood flows continuously via these circuits, your heart, and other organs:

  1. Pulmonary Circulation: This phase of the cycle transports blood that has lost its oxygen content from the heart, through the lungs, and back to the heart.
  2. The Systemic Circulation: This circulatory system transports blood, which carries nutrients, hormones, and oxygen from the heart to the rest of the body. As the body uses oxygen, nutrients, and hormones, waste products are absorbed by the blood in the veins.
  3. The Coronary Circulation: The coronary arteries are those that nourish your heart. This circuit is responsible for supplying the cardiac muscle with blood that is rich in oxygen. The coronary circuit subsequently sends the blood, now depleted of oxygen, back to the right atrium or upper chamber of the heart.

Types of Blood Vessels


Vascular structures called arteries carry blood away from the heart. They have thick walls and a small lumen to withstand the intense pressure caused by the heart's forced contractions. The arteries begin to segment as they move toward the more peripheral tissues, with every division having a smaller diameter and thinner wall. The aorta and the pulmonary artery are the two major arteries that leave the heart. The arteries that supply the heart's tissues with oxygenated blood are known as the coronary arteries.

Small and muscular tension vessels, or arterioles, take blood to organ systems, distributing arteries from the heart and their significant branches and conducting arteries with very flexible walls.

The conducting arteries have the most significant pressure, which lowers to the afferent arteriole, which has the lowest pressure. The tunica media (mid), tunica external (outside), and tunica intima (inner) are the multiple sections that make up the artery walls.


Muscular venules combine to form veins. Veins have a larger lumen and a thin wall than arteries. The inner layer of the vein contains significantly less muscle than the outermost surface, but the wall structure is comparable to that of arteries. Veins are capacitance vessels, which indicates they have a variable thickness wall and may expand to absorb high amounts of blood.

The valves, swellings of the tunica interna into the vascular lumen, are present in most peripheral veins. When the blood flow direction changes, valves are silently closed to stop the blood from flowing backwards into veins. Valves are missing in the thoracic and abdominal veins.


The body's tissues are covered in an extensive network of tiny capillaries. Capillaries join arteries and veins altogether. It is where the actual exchange of gases takes place. Oxygen-rich blood is transported from the streets to the capillaries. After passing through capillaries and into veins, the waste blood is delivered to the heart and lungs through circulation. The transfer of gases, nutrients, and wastes is facilitated because capillary walls are densely packed. These capillaries are so fine that red blood cells flow in a single line.

Signs of inadequate blood flow

Poor circulation has several indications and symptoms, which include:

  1. Chest pain
  2. Dizziness or breathlessness, loss of breathing tiredness pain, limb weakness, or numbness, swollen limbs, and slow or quick heartbeat or pulses

The signs and symptoms vary according to the type of cardiovascular disorder. For example, the aforementioned leg and foot problems might arise from peripheral arterial disease.

  1. Freezing feet or legs during walking or resting leg cramps
  2. Alteration of leg colour, change of thickness or colour of nails
  3. Losing hair on one's foot and legs
  4. On the legs and feet, there are ulcers that never heal.

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