Name the 5 layers of the epidermis from superficial to deep.
Stratum Corneum Stratum Lucidum Stratum Granulosum Stratum Spinosum Stratum Basale
Which epidermal layer is only present in thick skin?
Cell type that makes up the stratum basale.
Simple Columnar: this layer undergoes mitosis to replenish the skin cell population
How are cells in the stratum spinosum connected?
Most superficial epidermal layer that is not keratinized, however, contains granules of keratohyalin
In which epidermal layer do cells lose their nucleus?
Stratum Lucidum in thick skin
Stratum Corneum in thin skin
Name and describe the two layers of the dermis.
1. Papillary Layer: superficial dermal layer, forms dermal papilla into the epidermis, forms dermal ridges in thick skin (forms fingerprints), contains sensory nerve endings, Thin type I and Type II collagen fibers
2. Reticular Layer: deep dermal layer containing smooth muscle units, Type 1 collagen/ elastic fibers
Major components of the Hypodermis.
Glands, blood vessels
Arrector pili muscles
Name the Function of the two structures labeled in this picture.
The ones labeled KG and the "tail-less" arrows
KG: keratohyalin granule, found in the stratum granulosum keratinocytes to induce aggregation of filaggrin and trichohyalin filments and induce keratinization
The arrows are pointing to lamellar bodies that are exocystosed into intercellular spaces to act as a water barrer.
Where are melanocytes located and how do they function?
Located in the stratum basale.
The melanocytes respond to UV radiation and produce melanin. The melanin is sent up the dendritic processes and the tips of these processes are phagocytosed by the keratinocytes.
Location and function of Langerhans Cells.
Antigen Presenting Cells in the epidermis. They are mainly located in the stratum spinosum.
Function of this structure and its location.
Pacinian Nerve Ending: detects mechanical or vibratory pressure. Located in the Reticular layer of the dermis and hypodermis.
Location and function of the meissner corpuscle.
Found in the papilla of the dermal papillary layer. Touch, pressure, and temperature sensation.
Apocrine gland associated with the hair follicle.
Holocrine Gland associated with the hair follicle.
Sebaceous Glands: the nuclei gradually get smaller as the cell undergoes apoptosis to become sebum (oil) secretion
Layer of the hair follicle that contains melanocytes to give hair its color.
Matrix cells that surround the dermal papilla
What makes up the external root sheath of the hair follicle?
It's just a continuation of the epidermis.
Name the 3 layers of the inner root sheath
1. Henle's Layer: outermost, cuboidal cells
2. Huxley's Layer: middle layer, squamous cells
3. Cuticle of the hair follicle: inner layer, squamous cells
What is the:
Nail Matrix: germinative layer forming hard keratin
Eponychium: edge of skin covering the nail root
Hyponychium: skin nail junction
Lunula: cresent shaped white area at the end of the nail