Stratum granulosum
2750627
219714773
2008-06-16T15:25:55Z
Fratrep
4541225
Repairing link to disambiguation page - [[Wikipedia:Disambiguation pages with links|You can help!]]
{{Infobox Anatomy |
Name = {{PAGENAME}} |
Latin = stratum granulosum epidermidis |
GraySubject = 234 |
GrayPage = 1064 |
Image = Skinlayers.png |
Caption = Section of epidermis. (Stratum granulosum labeled at left, third from top.) |
Image2 = |
Caption2 = |
System = |
Precursor = |
MeshName = |
MeshNumber = |
DorlandsPre = s_25 |
DorlandsSuf = 12761233 |
}}
In [[microscopic]] views of [[skin]], the '''stratum granulosum''' layer of the [[Epidermis (skin)|epidermis]] lies between the [[stratum spinosum]], below, and the [[stratum lucidum]], above, in stratified squamous keratinized thick skin of palms and soles. Thin skin, which covers the rest of the body, lacks a definite stratum lucidum and stratum granulosum.
The '''stratum granulosum''' layer typically contains 1 to 3 rows of [[squamous]] [[cell (biology)|cell]]s with many small [[basophilic]] granules in their cytoplasm.
These prominent '''keratohyalin granules''' are not membrane-bound. Keratin bundles pass through the granules, which contain a phosphorylated histidine-rich protein and other cystine-rich proteins. The cells in the stratum granulosum contain also large amounts of [[filaggrin]], a protein thought to serve in bundling keratin. Membrane-coated lamellar granules (0.1 to 0.3 micrometers) are also present and contain lipids. The lamellar granules are exocytosed in this layer to generate a waterproof barrier. This waterproofing also prevents life-sustaining nutrient transport, and thus leads to the characteristic cell death of the outer layers of keratinized epithelium.<ref>L.P. Gartner and J.L. Hiatt, Color Textbook of Histology, 3rd ed., Elsevier, 2007, p 331-336.</ref><ref>Junqueria and Carneiro, Basic Histology Text & Atlas, 11th ed., McGraw-Hill, 2005, p 361.</ref>
This is the highest layer in the epidermis where living cells are found; the stratum lucidum above appears clear due to auto-digestion of cellular organelles.
This layer also includes '''lamellar granules''' and '''tonofibrils'''.
==References==
<references/>
==External links==
* {{BUHistology|08422loa}} - "Integument: thick skin"
{{anatomy-stub}}
{{integumentary_system}}
[[Category:Integumentary system]]
[[fr:Stratum granulosum]]
[[lt:Grūdėtasis sluoksnis]]