How Does The Circulatory System Work: Diagram, Steps, Function

What Is A Circulatory System?

The circulatory system is also called the cardiovascular system. It is a complex network of the heart, blood, and blood vessels. It aims to transport oxygen, nutrients, hormones, and cellular waste throughout the body. The circulatory system ensures the delivery of needs for every cell to live and function well and, ultimately, the removal of metabolic waste that may be detrimental to the then operation of a cell.

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It regulates all human physiological functions such as body temperature, pH levels, and fluid balance in the body for homeostasis. The body is prone to diseases and other serious problems if the circulatory system fails. Since the normal function of the circulatory system is important for a human being's health, it is part of the immune response and aids in the repair of tissues and, in general, the vitality, and well-being of an individual.

Components Of The Circulatory System

The circulatory system is constituted by basically the main parts that provide for blood flow within the complete human body.

Heart

• There are four chambers, two atria (upper chambers) and two ventricles (lower chambers).

• These chambers provide space for four valves—the tricuspid, pulmonary, mitral, and aortic which are used to control the flow of blood.

• The heart is a pump that pushes blood into the circulatory system.

• The blood is pushed to transport oxygen and nutrients to the tissues and, in turn, remove waste products.

Blood Vessels

• Arteries carry oxygenated blood from the heart. Veins carry deoxygenated blood back to the heart.

• Capillaries allow gas exchange, the exchange of nutrients at the tissue level, and the elimination of wastes in the blood.

• The arteries are endowed with various muscles which can withstand high pressure.

• Veins have numerous valves to prevent backflow.

• Capillaries are thin-walled to allow easy exchange of substances.

Blood

• The four components of blood are red blood cells, white blood cells, platelets, and plasma.

• Red blood cells are known for the transport of oxygen,

• White blood cells act as infection-fighting agents.

• Platelets contain the clotting mechanism of blood, and plasma is for carrying nutrients, some hormones, and waste, alongside water.

Diagram: Human Circulatory System

Functions Of The Circulatory System

The circulatory system performs activity through the interaction of many interwoven paths to move blood and, thus, oxygen from the lungs to the various tissues of the body.

Pulmonary Circulation

• Blood, which is deoxygenated, is pumped from the right ventricle into the lungs through the pulmonary arteries.

• In the lungs, blood is oxygenated, and from there, it enters the left atrium through the pulmonary veins.

• Carbon dioxide is exchanged for oxygen and this oxygen binds with the hemoglobin present in red blood cells.

Systemic Circulation

• The oxygen-rich blood from the left ventricle is pumped away through the aorta to the general body circulation, where the oxygen and nutrients are provided to cells.

• Deoxygenated blood, full of waste products, returns to the heart through veins, and the systemic circuit is completed.

Coronary Circulation

• The coronary arteries supply oxygenated blood to the heart muscle, which the heart cannot do without to work well.

• Adequate coronary circulation is thus needed to prevent ischemic conditions, such as those of heart attack.

Mechanisms Controlling Circulatory System

Several mechanisms take part in controlling the circulatory system so that it works properly or adjusts to the requirements of the body.

Heart Rate And Cardiac Output

• Stress, exercise, hormones, and autonomic nervous system inputs are a few stimuli that can increase or decrease heart rate.

• The volume of blood pumped by the heart in one minute is the cardiac output, and it is a key driver of the overall metabolic demand for oxygen from all the tissues in the body.

Blood Pressure Regulation

• The pressure exerted by blood on the walls of the arteries during systole is called systolic pressure, and the measure of the force when the heart relaxes is diastolic pressure.

• The autonomic nervous system is responsible for regulating the diameter of the blood vessels and the heart rate in response to appropriate stimuli to supply the heart with blood.

Homeostatic Mechanisms

• Regulation of blood volume and blood pressure is a function of the kidneys not independent of renal function.

• The long-term regulation of blood pressure is integrally related to the control of the balance of the body's fluids and electrolytes.

• Various sensors and effectors within the body affect the circulatory parameters, leading to homeostasis.

Disorders Of The Circulatory System

The derangements in the circulatory system may seriously impact overall health, so an apt approach to prevention and management is required.

Common Disorders

• Hypertension: Sustained higher-than-normal pressure, threatening damage to blood vessels and organs.

• Atherosclerosis: Fatty plaque deposition within arteries, which leads to reduced blood supply.

• Heart Attack: Obstruction of coronary arteries; subsequently, occlusion of the heart's muscle.

• Stroke: The interruption of blood flow to the brain resulting in neurological damage.

Prevention And Management

• Healthy eating, exercise, and abstaining from smoking and overconsumption of alcohol may prevent circulatory disorders.

• Medications to lower blood pressure and cholesterol, and surgical procedures such as angioplasty are used to treat and manage circulatory system disorders.

Circulatory System In Other Organisms

The circulatory system of different organisms varies, reflecting evolution to meet their different environments and needs.

Comparative Circulatory Systems

• Vertebrates usually possess a closed circulatory system in which blood is confined within vessels.

• Invertebrates mostly have an open circulatory system where the blood bathes the organs.

• Open systems facilitate direct contact of blood with the tissues.

• Closed systems allow the efficient exchange of nutrients and gases from tissues to blood because of the existence of capillaries.

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