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thin plate
a thin membrane that is one of the calcified layers that form bones
a tiny grain

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(組織・細胞などの)薄板,薄膜
小粒,微粒

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/01/17 16:14:30」(JST)

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Red arrows indicate secreted lamellar granules, and green arrows indicate lamellar granules in the cytoplasm. Scale bar = 200 nm.

Lamellar granules (otherwise known as membrane-coating granules (MCGs), lamellar bodies, keratinosomes or Odland bodies) are secretory organelles found in type II pneumocytes and keratinocytes. They are oblong structures, appearing about 300-400 nm in width and 100-150 nm in length in transmission electron microscopy images. Lamellar granules fuse with the cell membrane and release their contents into the extracellular space.^[1]

Role in lungs[edit]

In pneumocytes, the choline-based phospholipids that are stored in the lamellar bodies serve as pulmonary surfactant after being released from the cell.

Role in epidermis[edit]

In the upper spinous layer and stratum granulosum layer of the epidermis, lamellar bodies are secreted from keratinocytes, resulting in the formation of an impermeable, lipid-containing membrane that serves as a water barrier and is required for correct skin barrier function. These granules release components that are required for skin shedding (desquamation) in the uppermost epidermal layer, the stratum corneum.^[2] These components include lipids (e.g. glucosylceramides), hydrolytic enzymes (e.g. proteases, acid phosphatases, glucosidases, lipases) and proteins (e.g. corneodesmosin).^[3] Lamellar granules have been observed to contain distinct aggregates of the secreted components glucosylceramide, cathepsin D, KLK7, KLK8 and corneodesmosin. Transportation of molecules via lamellar granules is thought to prevent enzymes from interacting with their relevant substrates or inhibitors prior to secretion.^[3]

Recent work suggests that lamellar granules form a continuous membranous structure with the trans-Golgi network

Lamellar body secretion and lipid structure is abnormal in the epidermis of patients with Netherton syndrome, a skin disorder characterised by chronic inflammation and universal pruritus (itch).^[4]

References[edit]

^ Ishida-Yamamoto A, Kishibe M. (Mar 2011). "Involvement of corneodesmosome degradation and lamellar granule transportation in the desquamation process.". Med Mel Morphol. 44 (1): 1–6. doi:10.1007/s00795-010-0513-4. PMID 21424930. Cite uses deprecated parameters (help)
^ Descargues P, Deraison C, Bonnart C, Kreft M, Kishibe M, Ishida-Yamamoto A, Elias P, Barrandon Y, Zambruno G, Sonnenberg A, Hovnanian A. (Jan 2005). "Spink5-deficient mice mimic Netherton syndrome through degradation of desmoglein 1 by epidermal protease hyperactivity.". Nat Genet 37 (1): 56–65. doi:10.1038/ng1493. PMID 15619623. Cite uses deprecated parameters (help)
^ ^a ^b Ishida-Yamamoto A, Simon M, Kishibe M, Miyauchi Y, Takahashi H, Yoshida S, O'Brien TJ, Serre G, Iizuka H. (May 2004). "Epidermal lamellar granules transport different cargoes as distinct aggregates.". J Invest Dermatol. 122 (5): 1137–44. PMC 15140216. Cite uses deprecated parameters (help)
^ Fartasch M, Williams ML, Elias PM. (Jul 1999). "Altered lamellar body secretion and stratum corneum membrane structure in Netherton syndrome: differentiation from other infantile erythrodermas and pathogenic implications.". Arch Dermatol. 135 (7): 823–32. PMID 10411158. Cite uses deprecated parameters (help)

External links[edit]

Dr. Jastrow's Electron microscopic atlas
EM at meddean.luc.edu
"Lamellar body" at Dorland's Medical Dictionary

UpToDate Contents

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English Journal

Ultrastructural analysis of buckwheat starch components using atomic force microscopy.

Neethirajan S, Tsukamoto K, Kanahara H, Sugiyama S.SourceBiosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6445, USA. s.neethi@uoguelph.ca
Journal of food science.J Food Sci.2012 Jan;77(1):N2-7. doi: 10.1111/j.1750-3841.2011.02442.x. Epub 2011 Nov 1.
Morphological and structural features of buckwheat starch granules and nanocrystals were examined using atomic force microscopy and dynamic light scattering. Partially digested starch granules revealed a clear pattern of growth rings with the central core revealing lamellar structure. Atomic force m
PMID 22260119

Lamellar granule secretion starts before the establishment of tight junction barrier for paracellular tracers in mammalian epidermis.

Ishida-Yamamoto A, Kishibe M, Murakami M, Honma M, Takahashi H, Iizuka H.SourceDepartment of Dermatology, Asahikawa Medical University, Asahikawa, Japan. akemi@asahikawa-med.ac.jp
PloS one.PLoS One.2012;7(2):e31641. Epub 2012 Feb 6.
Defects in epidermal barrier function and/or vesicular transport underlie severe skin diseases including ichthyosis and atopic dermatitis. Tight junctions (TJs) form a single layered network in simple epithelia. TJs are important for both barrier functions and vesicular transport. Epidermis is strat
PMID 22328942

Japanese Journal

Involvement of corneodesmosome degradation and lamellar granule transportation in the desquamation process

ISHIDA YAMAMOTO Akemi,KISHIBE Mari
Medical molecular morphology : official journal of the Japanese Society for Clinical Molecular Morphology 44(1), 1-6, 2011-03-01
NAID 10029036346

Involvement of corneodesmosome degradation and lamellar granule transportation in the desquamation process

山本明美,Kishibe Mari
Medical Molecular Morphology 44(1), 1-6, 2011
… Proteases involved in the degradation of corneodesmosomes and their inhibitors are secreted from lamellar granules in the granular cell layer. … Abnormalities in transportation and secretion of lamellar granules underlie ichthyosis seen in certain human diseases. …
NAID 120004606768

Perturbation of lamellar granule secretion by sodium caprate implicates epidermal tight junctions in lamellar granule function

KURODA Shohei,KURASAWA Masumi,MIZUKOSHI Koji,MAEDA Tetsuo,YAMAMOTO Takuya,OBA Ai,KISHIBE Mari,ISHIDA YAMAMOTO Akemi
Journal of dermatological science 59(2), 107-114, 2010-08-01
NAID 10027401838