Why Understanding the Cardiovascular System Matters for Students
Let’s know what is the human cardiovascular system.
The human cardiovascular system is sometimes known as the blood-vascular, or simply known as the circulatory system.
This system includes the heart, which is a muscular pumping device, and an enclosed system of vessels known as the arteries, veins, and capillaries.
As the name human body cardiovascular system implies, the blood contained in the circulatory system is pumped by the heart around a closed circle or we can say around a circuit of vessels as it passes repeatedly through the various "circulations" of the body.
In adults, the survival of the developing embryo depends on the circulation of blood to maintain homeostasis as well as a favourable cellular environment. In response to this need, the human cardiovascular system emerges early in development and attains functional status long before any other major organ system and organs. Incredible as it seems, the primitive heart begins to beat regularly early basically in the fourth week following fertilization.
Cardiovascular System Anatomy and Role of the Cardiovascular System
The important role of the human cardiovascular system is in maintaining homeostasis. It depends on the continued and controlled circulation of blood across the thousands of kilometres of capillaries that permeate each tissue and reach each and every cell of the body.
Blood performs its ultimate transport function in the microscopic capillaries.
Nutrients along with other necessary materials pass from capillary blood into the liquids around the cells that the waste is removed.
Components of the Human Cardiovascular System
After discussing what is the cardiovascular system. Let’s discuss the components of the human cardiovascular system.
The human cardiovascular system has three main components: the heart, the blood vessel, and the blood itself.
The heart is the system’s pump and the blood vessels are said to be the delivery routes.
Blood can be said as a fluid that contains oxygen as well as the essential nutrients the body needs. Blood also carries the wastes which need to be removed.
Heart
We have already discussed the cardiovascular system definition.
The heart is similar to a muscular pump that provides the force vital to circulate the blood to all the various tissues in the body.
The function of the heart is vital because, to survive, the tissues need a continuous supply of oxygen as well as essential nutrients, and metabolic waste products have to be removed.
Deprived of these necessities, cells soon undergo irreversible changes which may lead to death. While blood is the means of transportation, the heart is the organ that keeps the blood moving across the vessels. The normal adult heart pumps around five litres of blood every minute of life.
Blood Vessels
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Functions of Bloodstream and Circulation:
Circulates oxygen and flushes out carbon dioxide.
Delivers nutrients to cells.
Removes metabolic waste from excretory organs and eliminates it.
Protects the body from sickness and infection.
Coagulation stops bleeding after being injured.
Transports hormones into cells and target organs.
Helps regulate body temperature.
Human Arterial System
Let’s discuss the human arterial system.
What are Arteries?
Arteries carry oxygen-rich blood away from your heart. They are thick hollow tubes that are very elastic which enable them to dilate and constrict (narrow) as the blood is forced down through the heart. The arteries branch out and branch out, becoming smaller until small arterioles become even more elastic. Arterioles supply the capillaries with oxygen-rich blood. The aorta, being the major artery of the organism, rakes blood from the heart, branches in other arteries which deliver oxygenated blood to the rest of the body.
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How Does the Cardiovascular System Work?
The human cardiovascular system is the heart, blood vessels, and blood. Blood contains oxygen as well as other nutrients which your body needs to survive. Blood is filled with oxygen and other nutrients your body needs to survive. Simultaneously, the body dumps waste products like carbon dioxide back into the blood, so they can be eliminated.
Maintaining blood flow to all the various parts of the body is one of the essential functions of this system. The veins transfer the used blood from the body into the heart and this blood is low in oxygen (as it has been taken out by the body) and the blood is high in carbon dioxide (as the body has unloaded it back into the blood).
All the veins drain into the superior as well as inferior vena cava which then drain into the right atrium. The right atrium pumps blood through the right ventricular. Then the right ventricle pumps blood to the pulmonary trunk, through the pulmonary arteries, and then into the lungs. In the lungs, the blood recovers the oxygen that we breathe and then removes the carbon dioxide. The blood then becomes rich in oxygen. From the lungs, blood drains into the left atrium and then is pumped into the left ventricle. Then the left ventricle pumps this oxygen-rich blood out into the aorta which then distributes it to the rest of the body through other arteries. The primary arteries that branch out of the aorta and take blood to specific areas of the body are given below:
Carotid arteries, the artery which takes blood to the neck and head
Coronary arteries, the artery which provides blood supply to the heart itself
Hepatic artery, the artery which takes blood to the liver with branches going to the stomach
Mesenteric artery, the artery that takes blood to the intestines
Renal arteries, the artery that takes blood to the kidneys
Femoral arteries, the artery that takes blood to the legs
This allows the body to use the oxygen in the blood to perform its normal functions. That blood will come back to the heart again through the veins and the cycle continues.
FAQs on Human Cardiovascular System Explained
1. What is the human cardiovascular system and what are its main components?
The human cardiovascular system, often called the circulatory system, is a vital organ system responsible for transporting substances throughout the body. It consists of three primary components:
- The Heart: A muscular organ that pumps blood.
- Blood Vessels: A network of tubes including arteries, veins, and capillaries, through which blood flows.
- Blood: A fluid connective tissue that carries oxygen, nutrients, hormones, and waste products.
2. What are the main functions of the cardiovascular system?
The primary function of the cardiovascular system is transportation and regulation to maintain homeostasis. Its key roles include:
- Transport of Oxygen and Nutrients: It delivers oxygen from the lungs and nutrients from the digestive system to all body cells.
- Removal of Waste Products: It carries metabolic wastes like carbon dioxide and urea to the lungs and kidneys for excretion.
- Hormone Circulation: It transports hormones from endocrine glands to their target organs.
- Protection: It contains white blood cells and antibodies to fight infection and platelets to clot blood after an injury.
- Thermoregulation: It helps regulate body temperature by distributing heat.
3. How does double circulation work in humans and why is it important?
Double circulation is a process where blood passes through the heart twice for each complete circuit of the body. It involves two pathways:
- Pulmonary Circulation: Deoxygenated blood is pumped from the right ventricle to the lungs for oxygenation and returns to the left atrium.
- Systemic Circulation: Oxygenated blood is pumped from the left ventricle to the rest of the body and deoxygenated blood returns to the right atrium.
4. What is the difference between arteries, veins, and capillaries?
Arteries, veins, and capillaries are the three types of blood vessels, differing in structure and function. Arteries carry oxygenated blood away from the heart (except the pulmonary artery), have thick, elastic walls to withstand high pressure. Veins carry deoxygenated blood towards the heart (except the pulmonary vein), have thinner walls, and contain valves to prevent the backflow of blood. Capillaries are microscopic vessels that connect arteries and veins, with extremely thin walls (one-cell thick) to allow for the exchange of gases, nutrients, and waste between blood and body tissues.
5. What is the cardiac cycle and what major events occur during one cycle?
The cardiac cycle refers to the sequence of events that takes place from the beginning of one heartbeat to the beginning of the next. It consists of two main phases:
- Systole: This is the contraction phase. The atria contract first (atrial systole) to push blood into the ventricles, followed by the ventricles contracting (ventricular systole) to pump blood out of the heart into the aorta and pulmonary artery.
- Diastole: This is the relaxation phase, where the heart chambers fill with blood.
6. Why is blood pressure measured with two numbers, such as 120/80 mmHg?
Blood pressure is measured with two numbers because it reflects the two phases of the cardiac cycle.
- The top number is the systolic pressure. It represents the maximum pressure your heart exerts on the artery walls while the ventricles are contracting (systole) to pump blood out.
- The bottom number is the diastolic pressure. It represents the minimum pressure in the arteries when the heart muscle is relaxing (diastole) between beats and refilling with blood.
7. How is the heartbeat regulated in the human body?
The human heartbeat is intrinsically regulated by a specialised cardiac muscle tissue known as the nodal tissue. The process is initiated by the Sino-Atrial (SA) node, located in the right atrium, which is why it's called the 'pacemaker'. The electrical impulse generated by the SA node causes the atria to contract. This impulse then travels to the Atrio-Ventricular (AV) node, which relays it to the ventricles via the 'bundle of His' and Purkinje fibres, causing them to contract. This ensures a coordinated and rhythmic heartbeat.
