What Is Inside your Veins?
Blood
Blood is a specialized body fluid that circulates throughout the cardiovascular system of humans and other vertebrates. It transports oxygen, nutrients, hormones, and waste products throughout the body. Blood also plays a role in immune defense and thermoregulation.
Components of Blood
Blood is composed of several different components, including:
* Plasma: The liquid component of blood that makes up about 55% of its volume. Plasma is composed of water, electrolytes, proteins, hormones, and waste products.
* Red blood cells (erythrocytes): These cells carry oxygen from the lungs to the rest of the body. They contain a protein called hemoglobin, which binds to oxygen molecules.
* White blood cells (leukocytes): These cells help fight infection. There are several different types of white blood cells, each with a different function.
* Platelets (thrombocytes): These cells help stop bleeding by forming blood clots.
Blood Clotting
When blood vessels are damaged, platelets and fibrinogen (a protein found in plasma) work together to form a blood clot. The clot plugs the hole in the blood vessel and prevents further bleeding.
Blood Type
Blood type is determined by the presence or absence of certain antigens on the surface of red blood cells. There are four main blood groups: A, B, AB, and O. People with the same blood type can donate blood to each other without any problems.
Blood Transfusions
Blood transfusions are sometimes necessary to replace blood that has been lost or to treat certain medical conditions. Blood transfusions can be life-saving, but they can also be dangerous if the donor and recipient have different blood types.
Blood Clots
Blood clots can form in arteries or veins. Arterial blood clots can cause heart attacks or strokes. Venous blood clots can cause deep vein thrombosis (DVT) or pulmonary embolism (PE). Blood clots can be life-threatening.
Blood Pressure
Blood pressure is the force of blood against the walls of blood vessels. High blood pressure (hypertension) can damage the arteries and lead to heart disease, stroke, kidney failure, and other health problems.