The Cardiovascular
System!
What is the Cardiovasuclar System?
The cardiovascular system/circulatory system allows blood, nutrients, minerals, and other substances to travel throughout the body using a system of blood vessels.
The cardiovascular system consists of blood vessels, as well as one of the most important organs in the human body, the heart!
The Heart
The human heart is a very complex organ that has many different aspects. The function of the heart is to receive oxygen-poor blood from the body, renew the blood with oxygen, and pump the blood back out into the body. The vessels that are used to allow this are veins and arteries. Veins carry blood to the heart, while arteries carry blood away from the heart. Another distinction between arteries and veins are that arteries usually carry oxygen-rich blood, while veins usually carry oxygen-poor blood. The only exception to this rule is with the pulmonary artery and the pulmonary vein.
The heart consists of four chambers. They are the left atrium, left ventricle, right atrium, and right ventricle.
Right Atrium:The right atrium receives oxygen poor blood from the superior or inferior vena cava. Then, the blood is sent to the right atrium, throught the tricuspid valve.
Right Ventricle: The right ventricle receives the oxygen-poor blood from the right ventricle. Then, this blood is sent out of the heart and towards the lungs, using the pulmonary artery, through the pulmonary valve. Although the pulmonary artery carries oxygen poor blood, it is still considered an artery because it carries blood away from the heart.
Left Atrium: Once oxygen-rich blood leaves the lungs, it heads back towards the heart, using the pulmonary veins. The blood then enters the left atrium using the pulmonary veins.
Left Ventricle: The left atrium pumps the blood into the left ventricle using the bicuspid valve. Here, the oxygen-rich blood is ready to be used by the body again, so the blood leaves the heart from the left ventricle. The blood goes through the aortic valve, and leaves the heart through the aorta.
The Heart Conduction System
The heart conduction system is what makes the heart relax and contract, forcing blood into and out of the heart.
Sinoatrial Node(SA Node)/Pacemaker: Sends signals telling the heart to contract.
Atrioventricular Node(AV Node): The impulses sent from the SA Node are delayed here.
Purkinje Fibers: The impulses are finally sent to the Purkinje Fibers, forcing the ventricles to contract and send blood out of the heart and into the rest of the body.
Electrocardiogram: The way that the heart conduction system can be monitored, using electrical signals.
Blood pressure: The blood pressure is the force of blood exerted on the blood vessels. A healthy blood pressure is considered to be around 120/80.
The steps of the Conduction System:
1. The atria and ventricles are at diastole, meaning they are relaxed.
2. The atria enter systole, forcing blood into the ventricles, which are still at diastole.
3. The atria enter diastole, allowing blood to enter from the body into the atria. During this time, the ventricles are at systole, when they force blood out of the body.
A potential problem with the cardiovasculars system is the possibility of a heart attack. A heart attack occurs when the coronary artery, the artery that brings blood to the heart itself, is stopped for some reason or another. This prevents the heart from pumping, leading to death. Another disease in teh cardiovascular system is a heart murmur. In fact, Mr. Hainey had one (not for the reason I will list below). A heart murmur is actually the sound of blood passing flowing. However, a heart murmur means something is wrong with the heart, usually a problem witha valve. This may also result from your heart beating faster, causing blood to move more blodd quicker than normal. At any rate, hear murmurs may or may not be deadly depending on the cause of the heart murmur.
Want to listen to Hank explaining the circulatory system? Here is a Crash Course video to help with your understanding.
By Shaan Sandhu