a
Red blood cells are produced in the bone marrow through a process called hematopoiesis and are released into the bloodstream to circulate throughout the body. Their life span is typically around 120 days before they are removed by the spleen and liver.
When they reach the end of their life span. :(
Yes, it is.
1-2 years, on average
Dead blood cells
Life in Cold Blood ended on 2008-03-03.
When RBCs are at the end of their life span (about 120 days), they are "disassembled" in the spleen where things like iron are conserved. Remaining waste products are sent to the liver/gallbladder for processing and excretion.
Red blood cells don't sleep and none of the other cells in the body need to sleep. Red blood cells do die when they've reached the end of their life cycle but until then they get continually pumped around the body, removing carbon dioxide and waste products from the tissues and providing oxygen and nutrients to the tissues.
No - they have very different shapes in order to perform their specific functions. Nerve cells are long with branched 'dendrites' at the end. There are many different blood cells, one of which - red blood cells - are almost circular with an indent in the middle.
red blood cells have an average lifespan of 120 days. At the end of this period, they are sent to the spleen where they are sequestered.
120-day life span, an RBC makes about 75,000 round trips between the lungs and tissues. At the end of its life, it returns to the bone marrow where it is removed by the reticuloendothelial system (particularly the liver, bone marrow, and spleen). Despite the constant destruction and production of RBCs (about 300 billion are destroyed and replaced each day), the body is able to maintain a fairly constant number
Science at this time can find no end to black holes. They seem to last forever.