Label the photomicrograph of thin skin. Epidermis Dermis Stratum granulosum Stratum spinosum Stratum basale Stratum corneum?
The correct answer and explanation is:
Labeling the Photomicrograph of Thin Skin:
- Epidermis: The outermost layer of the skin. This layer is composed of stratified squamous epithelium and houses the specific strata: stratum corneum, stratum granulosum, stratum spinosum, and stratum basale.
- Dermis: Found below the epidermis, this thicker layer contains connective tissue, blood vessels, nerve endings, and adnexal structures like sweat glands and hair follicles.
- Stratum corneum: The outermost layer of the epidermis, made up of dead, flattened keratinized cells that provide a protective barrier.
- Stratum granulosum: A thin layer of granular cells where keratinization begins. The cells contain keratohyalin granules that play a role in water retention and forming the skin barrier.
- Stratum spinosum: Known as the “spiny layer” due to the appearance of desmosomes connecting adjacent cells. It provides structural strength to the epidermis.
- Stratum basale (basal layer): The deepest layer of the epidermis, composed of a single layer of basal keratinocytes. This is where cell division occurs, producing new cells that migrate upwards.
Explanation:
The thin skin is found in most parts of the body, excluding the palms and soles. It differs from thick skin in that it lacks a prominent stratum lucidum and has fewer layers in the stratum corneum.
The epidermis is avascular, relying on diffusion from capillaries in the underlying dermis for nutrients. It has a layered organization to support both protection and renewal. The stratum corneum forms a waterproof barrier. The stratum granulosum contains cells undergoing keratinization. The stratum spinosum, with its desmosomal connections, ensures structural integrity. The stratum basale, closest to the dermis, houses mitotically active cells and melanocytes responsible for pigment production.
The dermis supports the epidermis structurally and nutritionally. It contains collagen and elastin fibers, giving skin its elasticity and strength. Together, the epidermis and dermis form a protective and functional unit that shields the body from environmental harm while maintaining homeostasis.