stratum granulosum
Học thuậtThân thiện
Definition
- Noun:
- A specific epidermal layer: The stratum granulosum is a thin, granular layer of the epidermis, located beneath the stratum corneum (or beneath the stratum lucidum on thick skin like palms and soles). It is characterized by cells containing visible keratohyalin granules, which are involved in the process of keratinization. Cells in this layer undergo terminal differentiation, lose their nuclei, and die as they move toward the skin surface.
Usage Examples
- Noun:
- The stratum granulosum is a critical barrier layer in the skin.
- Under the microscope, the cells of the stratum granulosum are identifiable by their dark-staining granules.
- Keratinization actively occurs within the stratum granulosum.
Advanced Usage
- In histological description: The term is used precisely to denote this specific layer in the sequence of epidermal strata (e.g., stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum).
- The biopsy showed a normal progression from the stratum spinosum to the stratum granulosum.
Variants and Related Words
- Stratum corneum (n): The outermost, horny layer of the epidermis, composed of dead, flattened keratinocytes.
- Stratum spinosum (n): The epidermal layer beneath the stratum granulosum, characterized by cells with a spiny appearance.
- Epidermis (n): The outermost layer of the skin, of which the stratum granulosum is a part.
- Granular layer (n): A common alternative name for the stratum granulosum.
Synonyms
- Granular layer: The most direct synonym in anatomical and dermatological contexts.
Notes on Meaning
This is a specialized anatomical and histological term. It has only one primary meaning referring to this specific skin layer. It is not used in idioms, phrasal verbs, or general language.
Noun
- the layer of epidermis just under the stratum corneum or (on the palms and soles) just under the stratum lucidum; contains cells (with visible granules) that die and move to the surface