what is the meaning of blood vessels
Answers
Answer:
blood vessels are actually ducts that carry blood throughout the body.
there are 3 kinds of blood vessesls-
- capillaries
- veins
- artillery
Answer:
Blood vessel
Blood vessel, a vessel in the human or animal body in which blood circulates. The vessels that carry blood away from the heart are called arteries, and their very small branches are arterioles. Very small branches that collect the blood from the various organs and parts are called venules, and they unite to form veins, which return the blood to the heart. Capillaries are minute thin-walled vessels that connect the arterioles and venules; it is through the capillaries that nutrients and wastes are exchanged between the blood and body tissues.
Explanation:
◉LET'S EXPLORE MORE
✯Types of Blood Vessels
Three types of blood vessels are:
- Arteries
- Veins
- Capillaries
☆Arteries
Arteries are strong tubes and muscular in nature. These blood vessels carry oxygen-rich blood from the heart to all the tissues of the body. Aorta is one of the main arteries that arise from the heart and branches further.
☆Veins
Veins are elastic blood vessels which carry deoxygenated blood from all parts of the body to the heart. An exception is the umbilical and pulmonary veins. The Pulmonary vein carries oxygenated blood to the heart from the lungs and umbilical vein carries oxygenated blood from the placenta to the foetus.
☆Capillaries
On reaching tissues, arteries branch further into extremely thin tubes called capillaries. Capillaries bring about the exchange of substances between blood and tissues.
✧Sinusoids
- Sinusoids are a special type of wider capillaries present in bone marrow, liver, lymph nodes, spleen and some endocrine glands. They may be continuous, discontinuous or fenestrated.
✯Layers of Blood Vessels
Both arteries and veins consist of three layers.
☆Tunica Intima:
- It is one of the innermost and thinnest layers of arteries and veins. It comprises of endothelial cells. They are in direct contact with the flow of blood.
☆Tunica Media:
- It is the middle layer of an artery or vein. Tunica media is made up of smooth muscle cells.
☆Tunica Externa:
- It surrounds tunica media. It is made up of collagen and also supported by the elastic lamina in arteries.
✯Functions of Blood
Blood is responsible for the following body functions:
☆Fluid Connective Tissue
- Blood is a fluid connective tissue composed of 55% plasma and 45% formed elements including WBCs, RBCs, and platelets. Since these living cells are suspended in plasma, blood is known as a fluid connective tissue and not just fluid.
☆Provides oxygen to the cells
- Blood absorbs oxygen from the lungs and transports it to different cells of the body. The waste carbon dioxide moves from the blood to the lungs and exhaled.
☆Transports Hormone and Nutrients
- The digested nutrients such as glucose, vitamins, minerals, and proteins are absorbed into the blood through the capillaries in the villi lining the small intestine.
The hormones secreted by the endocrine glands are also transported by the blood to different organs and tissues.
☆Homeostasis
- Blood helps to maintain the internal body temperature by absorbing or releasing heat.
☆Blood Clotting at Site of Injury
- The platelets help in the clotting of blood at the site of injury. Platelets along with the fibrin form clot at the wound site
☆Transport of waste to the Kidney and Liver
- Blood enters the kidney where it is filtered to remove nitrogenous waste out of the blood plasma. The toxins from the blood are also removed by the liver.
☆Protection of body against pathogens
- The White Blood Cells fight against infections. They multiply rapidly during the infections.