Category Archives: Cells

Telomeres

telomere is a region of repetitive nucleotide sequences at the end of a chromosome, which protects the end of the chromosome from deterioration or from fusion with neighboring chromosomes.Telomere regions deter the degradation of genes near the ends of chromosomes by allowing chromosome ends to shorten, which necessarily occurs during chromosome replication. Over time, due to each cell division, the telomere ends become shorter. (from medical school tumblr)

Large image at nerd-alert.net (link).  FISH detection of telomeres in metaphase human chromosomes (obtained from a lymphocyte), using a telomeric DNA probe. In this image, the telomeres light up yellow, whereas the rest of the chromosome is shown in blue.

 

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Purkinje Cells

Purkinje cells are some of the largest neurons in the human brain  with an intricately elaborate dendritic arbor, characterized by a large number of dendritic spines. Purkinje cells are found within the Purkinje layer in the cerebellum. Purkinje cells are aligned like dominos stacked one in front of the other.

Image source post-mitotic tumblr (link).  Photo credit Thomas Deerinck

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Neutrophils TEM

Granulocytes are a category of white blood cells characterized by the presence of granules in their cytoplasm.  They are also called polymorphonuclear leukocytes (PMN or PML) because of the varying shapes of the nucleus, which is usually lobed into three segments. In common parlance, the term polymorphonuclear leukocyte often refers specifically to neutrophil granulocytes, the most abundant of the granulocytes. Granulocytes or PMN are released from the bone marrow by the regulatory complement proteins. (from wikipedia)

Image by Rob Young.  From Wellcome images (link)

Fungal elements engulfed by neutrophils- col
Colour enhaced transmission electron micrograph
showing fungal bodies (blue) being engulfed by
polymorphonuclear leucocytes (yellow) deep in the
corneal stroma. The fungal hyphae within the cells
are approximately 1.1nm in diameter.

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Osteocytes SEM

Scanning electron micrograph of osteocytes in bone. The sample was prepared by embedding the bone in resin, which was subsequently etched with perchloric acid. This image was created by removing the entire mineral in the sample leaving a replica of the cells. Therefore, what is observed is the resin that filled the spaces in the bone and the spaces inside the cells.  (from Wellcome Images)

Osteocytes SEM from Wellcome images (link).  Credit: Kevin MacKenzie, University of Aberdeen

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