biology

• The heart is located between the lungs, behind the sternum.
• consists of the heart,blood and blood vessels
• the heart is a muscular pump or organ
• the heart is located between the lungs slightly to the left side
• the heart is approximately the size of a clenched fist
• the function of the heart is to pump blood into blood vessels and throughout the body
• blood is a living fluid tissue mostly made of a pale yellow liquid called plasma
• the blood consists of 55% plasma, 4% white blood cells and platelets and 41% red blood cells
• plasma is a pale yellowish liquid consisting mainly of water and dissolved substances such as glucose,salts,gases,proteins and waste products
• the function of plasma is that it acts as a medium to carry dissolved substances throughout the body
• plasma also carries the blood cells from one part of the body to another
• blood cells comprise of 3 types namely:red blood cells,white blood cells,platelets
• red blood cells are more abundant in the blood[41%] than white blood cells
• a red blood cell is about 8 micrometers in diameter and has a biconcave shape
• they are produced in the red bone marrow
• red blood cells have no nucleus and cannot divide
• red blood cells contain a red pigment called haemoglobin which is a protein
• RCBs are adapted to carry oxygen because:they have no nucleus thus can acommodate more haemoglobin,they have cytoplasm where haemoglobin is stored,have a flattened shape and biconcave sides increasing surface area allowing oxygen to diffuse in and out rapidly