I obtained this small collection of six slides new from Brunel Microscopes Ltd – looking at the slides via my Zeiss IM microscope today I could see the following (all pictures below are with the same Bresser MikrOkular camera and 40x objective so at same scale):
(i) Mammalian red cells all are missing their nucleus – the process of production of these cells involves loss of the nucleus before the cells are released from the bone marrow – the cell hence has a doughnut shape and only lasts three months as it is already effectively “dead” without its nucleus.
(ii) Sometimes nucleated forms of red cells are released from the marrow and a couple of these can be seen in my slides – alternatively I might be wrong and these might be white cells – I am not sure!
Close up of nucleated cells in above image (below):
(iii) Bird, fish and amphibian red cells are nucleated – keep their nucleus after production. Does this mean that they are closer together on the evolutionary scale or does it mean that nucleation of the red cells better suits aspects of the environments in which all three live as opposed to the environment in which mammals live?
(iv) There are differences in size and colour between red cells of different types of animal – for example, compare the views I obtained today of cells above in fish and bird blood with that I found from frog blood below.