Red blood cell being dissolved in body fluid) was an important step in the evolution of vertebrates as it allows for less viscous blood, higher concentrations of oxygen, and better diffusion of oxygen from the blood to the tissues. The size of red blood cells varies widely among vertebrate species; red blood cell width is on average about 25% larger than capillary diameter, and it has been hypothesized that this improves the oxygen transfer from red blood cells to tissues. The red blood cells of mammals are typically shaped as biconcave disks: flattened and depressed in the center, with a dumbbell-shaped cross section,
The Blood Cell The Blood Cell The Blood Cell is a BBC Books original novel written by James Goss and based on the long-running British science fiction television series "Doctor Who". It features the Twelfth Doctor and Clara Oswald. The book was released on 11 September 2014 along with "Silhouette" and "The Crawling Terror". "The Blood Cell" gained generally positive reviews, calling it an "effective chiller". Most of them commented the unusual way of narration from the first-person perspective of the administrator of the prison in which the book is set known as the Governor. More grim and darker tone is also noted.