Integument Flashcards
(56 cards)
The functions of this include barrier for protection, sensation and excretion, thermoregulation, and synthesis of Vitamin D3.
Integument
What is the integument composed of?
Epidermis (epithelial layer – ectoderm)
Dermis (CT layer – mesoderm)
Deep to the dermis lies the ________, a loose CT layer that binds the skin to underlying tissues and corresponds to the superficial fascia.
Hypodermis
The epidermis is made of what epithelial cell type?
Stratified squamous keratinized epithelium
***Composed of keratinocytes
These are irregular projections at epidermal-dermal junction. They interdigitate with epidermal ridges to strengthen adhesion.
Dermal papillae
Fingerprints, palms, and soles are (THICK/THIN) skin.
Thick (five layers)
Glands, hair follicles, and most of the body is (THICK/THIN) skin.
Thin (four layers)
The epidermis consists of 4-5 layers which are…
Stratum corneum Stratum lucidum Stratum granulosum Stratum spinosum Stratum basale
The epidermis has 4-5 layers consisting of what different types of cells?
Keratinocytes
Melanocytes
Merkel cells
Langerhans cells
This is the predominant cell type of the epidermis. It produces keratins (85 percent of cells) and participate in the epidermal water barrier. Will produce ‘cornified’ cells, full of keratin.
Keratinocytes
This layer of the epidermis has a single-layer of keratinocytes with stem cells interspersed. It is mitotically active, and made of cuboidal/low columnar cells. Contains melanin.
Stratum basale
The Stratum basale is bound apically by ________ and basally by _________.
Desmosomes
Hemidesmosomes
This is the thickest layer of the epidermis. It has polyhedral cells with central nuclei and spiny processes. Keratin filaments assemble here into microscopically visible bundles called tonofibrils.
Stratum spinosum
***Tonofibrils associated with desmosomes, resulting in a spiny appearance. Called “prickle layer”
This layer of the epidermis consists of three to fiver layers of flattened cells. It is filled with keratohyaline granules and lamellar granules (small ovoid structures containing lipids and glycolipids).
Stratum Granulosum
***Lamellar granules undergo exocytosis and release lipids, creating an impermeable layer that protects against water loss
In the Stratum Granulosum, the keratohyaline granules are composed of…
Tonofibrils + Filaggrin (bundling protein)
In this layer of the epidermis, there is 15-20 layers of squamous, keratinized cells filled with filamentous keratins. Cells are anucleate and coated by an extracellular layer of lipids.
Stratum Corneum
In the Stratum Corneum, fully keratinized ‘cornified’ cells called ________ are continuously shed as desmosomes break down.
Squames
This epidermal layer is found ONLY in thick skin. It is a thin, translucent layer of flattened eosinophilic keratinocytes held together by desmosomes. Nuclei and organelles have been lost and the cytoplasm is almost exclusively keratin filaments.
Stratum Lucidum
These cells produce melanin and transfer it to keratinocytes. They are neural crest-derived and scattered along the Stratum Basale.
Melanocytes
This is a pigment protein that protects nuclei form UV radiation.
Melanin
In an ________-________ unit, one melanocyte maintains an association with a specific number of keratinocytes (1:10).
Epidermal-melanin
What are the steps in melanin production?
Tyrosinase converts Tyrosine into DOPA, DOPA is then polymerized into Melanin
Melanin production reactions occur in membrane-bound organelles called __________. As melanin increases these organelles, they are converted into _________. These are then transferred to keratinocytes where they give the “pigment donation”.
Premelanosomes
Melanosomes
The cells are APCs that provide defense against pathogens (developed from monocyte precursor). Identifiable in Stratum Spinosum, and appear as pale cytoplasm with long processes.
Langerhans cells
