The Human Circulatory System: Students must understand the human circulatory system to score well in the exam. The circulatory system is made of human blood vessels and the heart. The circulatory system provides nutrients, oxygen, and hormones to muscles, organs, and tissues throughout the body. Along with that, the circulatory system eradicates waste from organs and cells so the human body can dispose of it.

The heart pumps blood to the body through blood vessels, veins, and arteries. That is why the circulatory system is also known as the cardiovascular system. Cardio signifies the heart, while vascular refers to blood vessels.

The circulatory system transfers blood to all body tissues to make them function. Now let us know the function of the circulatory system.

The Human Circulatory System: The Function 

The circulatory system helps the body get rid of waste products, which include the following:

• Carbon dioxide from respiration (breathing)
• Waste from things one eats and drinks
• Other chemical byproducts from organs

 The Human Circulatory System: The Working System

Blood vessels include arteries, veins, and capillaries. They support the operation of your circulatory system. Blood is regularly circulated throughout the human body via these blood veins, heart, and lungs. Here’s how:

1. Oxygen-poor blood, blood that’s low in oxygen, is delivered to the lungs through the right ventricle, the lowest pumping chamber of the heart. The pulmonary trunk or the main pulmonary artery carries blood.
2. In the lungs, blood cells absorb oxygen.
3. The heart’s left atrium receives oxygenated blood from the lungs through pulmonary veins (upper heart chamber).
4. Blood with oxygen is sent from the left atrium to the left ventricle (lower chamber). Through the arteries, this heart’s muscular portion pumps blood out to the body.
5. The human circulatory system functions with the help of blood vessels that include arteries, veins, and capillaries. These blood vessels work with the heart and lungs to continuously circulate blood through your body. Here’s how:
6. Oxygen-poor blood is delivered to the lungs through the right ventricle, the lowest pumping chamber of the heart, while the pulmonary trunk or the main pulmonary artery carries blood.
7. In the lungs, blood cells absorb oxygen.
8. The heart’s left atrium gets oxygenated blood from the lungs through pulmonary veins (upper heart chamber).
9. Blood with oxygen is sent from the left atrium to the left ventricle (lower chamber). Through the arteries, this heart’s muscular portion pumps blood out to the body.
10. Blood picks up and excretes nutrients and hormones and circulates your body and organs.
11. Deoxygenated blood and carbon dioxide are returned through the veins to the heart, which pumps blood to the lungs.
12. Human lungs get rid of the carbon dioxide at the time of exhalation.

The Human Circulatory System: The Parts 

The parts of the circulatory system are given below.

• Heart – The heart is a muscular organ. It pumps blood throughout the body.
• Blood vessels – Blood vessels include arteries, capillaries, and veins.
• Blood – Blood comprises white and red blood cells, platelets, and plasma.

What Does the Circulatory System Circuit?

The circulatory system includes three circuits. Continuously, blood circulates through the heart and these below circuits.

• The pulmonary circuit

The pulmonary circuit carries blood without oxygen. It carries blood from the heart to the lungs. After that, the pulmonary veins return oxygenated blood to the heart.

• The systemic circuit

In this systemic circuit, blood full of nutrients, oxygen, and hormones travels from the heart to the rest of the body. The blood picks up waste products in the veins as the body utilizes nutrients, oxygen, and hormones.

• The coronary circuit

The heart’s arteries refer to the coronary. This circuit supplies the heart muscle with oxygenated blood. After that, the coronary circuit returns oxygen-poor blood to the right upper chamber of the heart, also known as the atrium, and sends oxygen to the lungs.

Different Types of Blood Vessels

Three main types of blood vessels are there.

• Arteries

Arteries are thin, muscular tubes. They carry oxygenated blood from the heart to other parts of the body. The largest artery in the body is the aorta. It starts at the heart and then ascending aorta travels to the chest. After that, it goes down into the stomach (descending aorta). The coronary arteries branch off the aorta. After that, they branch into smaller arteries (arterioles) as they get distant from the heart.

• Veins

These blood arteries deliver the heart with blood that has lost oxygen. Veins (venules) start small and grow bigger as they move closer to the heart. The heart receives blood from two major veins. Blood from the upper body (head and arms) is transported to the heart by the superior vena cava. Blood is transported to the heart via the inferior vena cava from the lower body (stomach, pelvis, and legs). Leg veins feature valves to prevent blood flow backwards.

• Capillaries

These blood channels link veins and tiny arteries (arterioles) (venules). Oxygen, carbon dioxide, nutrients, and waste materials can travel through capillaries’ thin walls and into and out of cells.

The Circulatory System Organs

The heart is the only circulatory system organ. Blood travels from the heart to the lungs to acquire oxygen. The lungs are one of the most crucial parts of the respiratory system. After that, the heart pumps oxygenated blood to the rest of the body through arteries.

Conditions that Affect the Circulatory System

The health of the circulatory system can be affected by different conditions. Check the details below.

• Aneurysms

Aneurysms is a condition that occurs when an artery wall enlarges and weakens. The weak spot bulges because blood flows through the artery. The weak spot may also tear, and it can cause a life-threatening rupture. Aneurysms can affect any artery. But the most common ones are brain aneurysms, aortic aneurysms, and abdominal aortic aneurysms.

• High blood pressure

Arteries circulate blood throughout the body by working hard. When the force of blood gets too high against the blood vessel walls, a human gets high blood pressure. When the arteries become less elastic or stretchy, less blood and less oxygen reach organs like the heart. High blood pressure puts the human body at risk of strokes, cardiovascular disease, and heart attacks.

• Plaque deposits

Fat and other chemicals may accumulate in the blood due to diabetes and high cholesterol. On the arterial walls, these chemicals accumulate as plaque-like deposits. Atherosclerosis, also known as clogged or hardened arteries, is an ailment. Atherosclerosis makes heart attacks, kidney disease, coronary artery disease, peripheral artery disease, and other artery illnesses more likely.

• Venous disease

Venous Disorders typically affect veins in the lower body. When blood can’t return to the heart and collects in leg veins, issues like chronic venous insufficiency and varicose veins develop. A potentially fatal pulmonary embolism can result from deep vein thrombosis (DVT), a blood clot in the legs.

How Should We Prevent Circulatory System Problems?

Follow these below steps to protect the health of the circulatory system.

• A minimum of 150 minutes of physical activity is necessary for the human body every week.
• A heart-healthy diet full of vegetables and fiber is a must. Along with that, humans must avoid processed foods.
• We should find different ways to avoid stress completely. 
• Maintaining a healthy weight is also crucial for the human body.
• We must manage conditions like high blood pressure, high cholesterol, and diabetes.
• Smoking is always injurious in these conditions. Therefore we must quit it.

How Large is the Circulatory System?

A human body consists of over 60,000 miles of blood vessels. They circulate 1.5 gallons of blood daily.

What are the Definitions of Red Blood and Blue Blood?

Blood is always red. The protein in red blood cells called haemoglobin, which is high in iron, combines itself with oxygen to give blood its red colour. Red blood contains a high oxygen content. Your veins carry blood with little oxygen. Due to the possibility of blue-looking veins under the skin, we commonly know this as blue blood. Although the veins are blue, the blood itself is crimson due to low oxygen levels.

Do Arteries Only Carry Oxygenated Blood?

Yes, for most of the parts, arteries only carry oxygenated blood. But there are exceptions like pulmonary arteries and veins. While pulmonary arteries transfer deoxygenated blood to the lungs, pulmonary veins work to return the oxygenated blood to the heart.
The circulatory system plays a crucial role in keeping humans alive. Blood vessels transfer blood to the lungs for oxygen. After that, the human heart pumps oxygen-rich blood to the rest of the body through arteries. On the other hand, veins help the body get rid of waste products. Conditions like atherosclerosis, high blood pressure, and high cholesterol can affect the circulatory system’s health. Anyone with one of these conditions must talk to a healthcare provider. Doctors can guide them on the steps they can take to protect their cardiovascular health.

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