where are red blood cells made in the human body
Red blood cell 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; they can be viewed as sacks of hemoglobin, with a plasma membrane as the sack. Approximately 2.4 million new erythrocytes are produced per second in human adults.[2] The cells develop in the bone marrow and circulate for about 100â€“120 days in the body before their components are recycled by macrophages. Each circulation takes about 60 seconds (one minute).[3] Approximately a quarter of the cells in the human body are red blood cells.[4][5] Nearly half of the blood's volume (40% to 45%) is red blood cells.
Stomach In classical anatomy, the human stomach is divided into four sections, beginning at the gastric cardia,[6] each of which has different cells and functions.
Red blood cell As a result of not containing mitochondria, red blood cells use none of the oxygen they transport; instead they produce the energy carrier ATP by the glycolysis of glucose and lactic acid fermentation on the resulting pyruvate.[40][41] Furthermore the pentose phosphate pathway plays an important role in red blood cells; see glucose-6-phosphate dehydrogenase deficiency for more.
Red blood cell Adult humans have roughly 20–30 trillion red blood cells at any given time, constituting approximately 70% of all cells by number.[19] Women have about 4–5 million red blood cells per microliter (cubic millimeter) of blood and men about 5–6 million; people living at high altitudes with low oxygen tension will have more. Red blood cells are thus much more common than the other blood particles: there are about 4,000–11,000 white blood cells and about 150,000–400,000 platelets per microliter.