20 BOY SCOUTS OF AMERICA Campmasters With the exception of summer camp programs, our camps are served by campmasters â volunteers who staff the office, provide weekend programs, serve our campers and ensure the safety and well-being of our visitors.
In humans, mature red blood cells are flexible and oval biconcave disks. They lack a cell nucleus and most organelles, in order to accommodate maximum space for hemoglobin. Approximately 2.4 million new erythrocytes are produced per second in human adults. The cells develop in the bone marrow and circulate for about 100â120 days in the body before their components are recycled by macrophages. Each circulation takes about 20 seconds. Approximately a quarter of the cells in the human body are red blood cells.
Most blood cells are made in your bone marrow. They are constantly being made and replaced. How long a cell lasts before being replaced is called its lifespan. Your blood is made up of 4 components: red blood cells, white blood cells, platelets, and plasma. Blood Components Red blood cells (erythrocytes) Red blood cells carry oxygen from your lungs to your tissues. They also bring carbon dioxide back to your lungs. Red blood cells make up about 44% of your blood. The lifespan of a red blood cell is around 120 days. White blood cells (leukocytes) White blood cells fight infection and help you develop immunity to disease. They make up less than 1% of your blood. There are 3 types of white blood cells: granulocytes, monocytes, and lymphocytes. Each type has specific functions. There are 3 subtypes of granulocytes: Neutrophils, which help fight bacterial and fungal infections. Basophils, which are associated with immune responses, although their exact function isnât well known.