â¢ The cell cycle is a series of events that takes. place from one cell division to the next. â¢ The time is takes to complete a cell cycle is. not the same in all cells.
A neuron is a nerve cell. The brain is made up of approximately 100 billion neurons. Neurons are similar to other cells in the body in some ways such as: Neurons are surrounded by a membrane. Neurons have a nucleus that contains genes. Neurons contain cytoplasm, mitochondria and other organelles.
An adult brain weighs about 1.5kg (3.3lb) and contains about 90 billion nerve cells. As well as nerve cells our brains have about 90 billion other cells, plus blood vessels to help supply the nutrients and oxygen it needs. During dementia, nerve cells in different areas of the brain become damaged and eventually die.