Skin’s top layer is a prototypical “squamous epithelium”: it contains layers of densely packed epithelial cells that form continuous sheets. The sheets stack up on top of each other, and then the whole stack sits on a basement membrane, which supports the epithelial and serves as a source of new cells for growth and regeneration. Epithelia have nerves but no blood vessels.
Epithelia are classified by the shape of the top cells. For the skin epidermis, these cells have a “polygon” shape when viewed from above, and thus, the epidermis is called a “squamous epithelium.”
Image: Here cultured epithelial cells are imaged via multiphoton microscopy, illustrating the classic polygon shape of “squamous epithelial cells.” Cell nuclei were stained for DNA using Hoechst 33342 (cyan), the Golgi apparatus expres targeted GFP (green), and actin was stained using fluorescent phalloidin (magenta).
Embryo of the dwarf cuttlefish, Sepia bandensis, stained with phalloidin (F-actin; green), DAPI (nuclei, blue), and anti Pax 3/7 (MAb DP312, red). The developing cuttlebone (purple) and eyes (yellow) were rendered using the DIC image collected during the confocal scan. The F-actin staining (green) reveals the developing musculature and brain, while Pax 3/7 (red) is expressed in a subset of neurons in the brain as well as two patches of epithelia in the mantle and portions of the arms and tentacles. The cuttlebone (purple) is a chambered, gas-filled internal shell made of aragonite that provides buoyancy control. Within each eye (yellow), the developing lens is seen as an internal sphere. Seven of the eight arms are visible along with the two tentacles that have sucker-covered ends.
Me in my head: “The Amanita phalloides holds three different poisons. There is amanitin, which works slowly and is most potent. There is phalloidin, which
acts at once, and there is phallin, which dissolves red corpuscles, although it is the least potent. The first symptoms do
not appear until seven to twelve hours after eating, in some cases not before twenty-four or even forty hours. The
symptoms begin with violent stomach pains, cold sweat, vomiting…”
Description: Confocal micrograph of osteoblast cells labeled with Alexafluor 488 that stains alpha tubulin (green) and phalloidin marking the actin (purple) and DAPI highlighting the nucleus (yellow). Osteoblasts originate in bone marrow and contribute to the production of new bone. These cells build up the matrix of bone structure and as bone is continually being reabsorbed and regenerated these are very crucial cells. Osteoblasts make up bone and osteoclasts break it down.
Confocal image (extended focus Z stack) of a Crepidula fornicata (slipper limpet) veliger larva. Stained with phalloidin (F-actin; purple), DAPI (cell nuclei, blue), anti-serotonin (yellow), and anti-acetylated tubulin (red). The shell (green) image was created from the DIC picture collected during the confocal scan. The C-shaped line of nuclei are cells at the edge of the velum; the acetylated tubulin (red) staining reveals the ciliated surface of the velum. The F-actin staining (purple) highlights the main larval retractor muscle. Serotonin (yellow) reveals the serotonergic neuron cell bodies and axons. Joyce Pieretti (University of Chicago), Manuela Truebano (Plymouth University), Saori Tani (Kobe University) and Daniela Di Bella (Fundacion Instituto Leloir)
Courtesy of Marine Biological Laboratory, Woods Hole, and Development