Integumentary 1 Flashcards
What structures does the integumentary system contain?
Skin, hair, nails, glands, adipose tissue, muscles and nerves
What structures of the integumentary system contain epithelium tissue
epidermis, blood vessels, sweat glands, sebaceous glands, hair
What structures of the integumentary system contain connective tissue
dermis, hypodermis, blood vessels
What structures of the integumentary system contain muscle tissue
blood vessels, arrector pili muscles
What structures of the integumentary system contain nervous tissue
sensory receptors, blood vessels
What the the three layers of skin and what are they made of?
Epidermis (stratified cuboidal keratinised epithelium)
Dermis (loose connective tissue -papillary layer and dense irregular connective tissue - reticular layer
Hypodermis (adipose and dense irregular connective tissue)
What is the purpose of keratinisation?
To produce lamellar bodies as tonofilamenta and keratohylaine granules combine.
What are the 5 layers of epidermis?
Stratum basale Stratum spinosum Stratum granulosum Stratum lucidum (only in thick skin) Stratum corneum
What are the layers of dermis?
Papillary layer (loose CT) Reticular layer (dense irregular CT, the reticular layer is the largest layer in the dermis).
What non-keratinocytes are in epidermis and in which layers?
Merkel cells found in stratum basale.
Melanocytes found in stratum basale
Langerhans cells found everywhere but mostly in stratum spinosum.
Why are stratum lucidum and corneum acidophilic
They are filled with protein and are dead so have no nuclei
What are keratinocytes?
Keratinocytes are responsible for the visible layers of the skin. They contain tonofilaments and keratohyaline granules (when they combine keratin is formed). Keratinocytes also secrete glycolipids (lamller bodies) Keratinocytes produce in the basale layer from mitosis. As they progress through the layers, keratinocytes are removed by abrasion
What is keratinisation?
It is the process as keratinocytes progress through the epidermis. It goes from cuboidal, irregular spiny, flattened with granules and then squamous. Lamellar bodies are also produced. It is done by cell divison.
Describe the stratum basale
Contain merkel cells and melanocytes. Contains many cell junctions (hemidesomones and desmosomes). Production of keratinocytes also occurs here. Melanin granules are also found here
Describe the stratum spinosum
The largest layer of the epidermis. Langerhans cells are identified here. The intercellular bridges are held by demosomes. Tonofilaments (found in keratinocytes) are found here
Describe the stratum granulosum
As the tonofilments and keratohyaline granules combine, glycolipids (lamellar bodies) are produced.
Describe the stratum lucidum and corenum
Found only in thick skin (lucidum). dead skin filled w/ keratin. Surface keratin is lost through abrasion
Describe the lifespan of keratinocytes
The lifespan is shorter the high friction areas (25-30 days) and is longer in ares w/ low friction (40-50 days). Diseases (ie psorasis) can influence this.
Describe merkle cells
Merkle cells are found in the basale layer. They are associated with light touch
Describe melanocytes
Produce melanin. located in the stratum basale.
What are the three types of melanin?
Eumelanin (black/brown)
pheomelanin (pink/skin)
Neuromelanin (in neurons)
Describe langerhans cells
Langerhans cells are dendritic cells and are associated w/ the innate immune system.
Describe the difference between thick and thin skin
Thick skin is hairless whilst thin skin contains hair however some thin skin such as the border of the lips nipples penis and clitoris do not contain hair.
Both skins have sweat glands (apocrine sweat glands = thin).
Thick skin has thicker dead cell layers (lucidum +corneum) and folds to better attach the epidermis to dermis. This is done by dermal pipillae.
