Proud to be an American!

LAB 14 - ADAM Cardiovascular CD

Your cardiovascular system transports important substances such as oxygen and nutrients between tissues and organs. It also helps transport and eliminate waste products. Your heart, blood, and blood vessels are all components of the cardiovascular system

The Heart
  The heart is the transport system pump, and the blood vessels are the delivery routes. Using blood as the transport medium, it propels oxygen, nutrients, wastes, and other substances to and past the body cells. The heart is a hollow, muscular pump that is divided into 4 chambers. The two top chambers are called atria, and the two lower chambers are called ventricles. The two types of chambers in the heart perform different functions: the atria collect the blood that enters the heart and push it to the ventricles, which push blood out of the heart and into the arteries. In order to move blood through your heart, your heart chambers undergo alternating periods of relaxation and contraction. This allows the chambers to fill up with and pump blood. The right atrium of the heart receives deoxygenated blood from two major veins, the superior vena cava and the inferior vena cava. When this chamber contracts, blood moves out of the right atrium and into the right ventricle through the tricuspid valve. Once the right ventricle has sufficiently filled with blood, this chamber contracts, pumping blood via the pulmonary arteries into the pulmonary circuit of the cardiovascular system. Newly oxygenated blood enters the left atrium of your heart through your pulmonary veins. Once this chamber is filled with blood, the left atrial wall contracts, pushing blood into the left ventricle through the bicuspid valve. After the left ventricle has filled with blood, this chamber contracts, forcing blood out of the ventricle and into the aorta. From the aorta, blood travels through the systemic circuit of the blood vessels, bringing oxygen to tissue cells throughout the body.

The heart wall is composed of cardiac muscle which contains nuclei, intercalated disks, and cardiac myofibrils. The intercalated disks contain two types of junctions, the desmosomes which, hold adjacent muscle cells together, and the gap junctions that allow stimulating impulses to move across the heart from cell to cell.

Normal EKG Tracing P wave - atrial depolarization QRS complex - ventricle depolarization T wave - ventricular repolarization

Blood Vessels
Blood vessels are intricate networks of tubes that transport blood throughout the entire body. Blood vessel walls are composed of three layers: the tanica intima (endothelium or inner most layer), tanica media (the middle layer), and the tunica advetitia . The space in the center of blood vessels in called the lumen.

The tunica adventitia - is the strong outer covering of arteries and veins. It is composed of connective tissue as well as collagen and elastic fibers. The tunica media - is the middle layer of the walls of arteries and veins. It is composed of smooth muscle and elastic fibers The tunica intima - is the inner layer of arteries and veins. In arteries this layer is composed of an elastic membrane lining and smooth endothelium that is covered by elastic tissues.