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33 Cards in this Set
- Front
- Back
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What does skin do?
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Protects, sensory, respire, excrete, thermoregulate, movement, homeostasis, nourishment, communication, vit. D synthesis
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Structure of Integument: 4 layers
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non-living epidermal covering, epidermis, dermis, body wall
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Non living epidermal covering
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from the ectoderm. A mucoid coat or cornified cells made by epidermis and dermal derivatives poking through
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Epidermis
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from the ectoderm, maintained by cell division to make secretory glands and house speciailized derivatives of cornified cells.
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Dermis
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Mostly mesoderm, collagen and connective tissue. Made to be tough, it holds components in place and produces bony derivatives
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Body wall
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thin layer of somatic mesoderm connective tissue.
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Aquatic integuments
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A thick epidermis and have many glands to upkeep that mucous coat
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Terrestrial integuments
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A thin epidermis and either thin stratum corneum and large glands or thick stratum corneum and dermal derivitives
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Development of the cornified layer
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cells divide, move out, synthesize keratin, become flat, die. Cyclic in squamates and in dandruff in mammals
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Cornified structures become specialized for?
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Protection, offense, defense, thermoregulation, moisture barrier
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Basic cornified structure is illustrated by?
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Epidermal scales
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Where are epidermal scales found?
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Squamates, crocs, birds, a few mammals
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What are specialized structures from the corneum?
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Scales and derived scales such as epidermal scales, lamprey teeth, tadpole beaks, hair, feathers, claws, nails, hooves, beaks, bovine horns, hair horns, baleen, palatine rugae, ischial tuberosities, rattle
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What is the dermis composed of?
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Collagenous connective tissue
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Is the dermis flexible?
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Yes. It can stretch and rebound
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What are the universal components from outside the dermis?
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Blood vessels, nerves, pigment cells
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Other components from outside the dermis?
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Lyphatics, gases of glands, bases of other epidermal derivatives
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What are the two primary contributions of dermis to the integument?
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Holding components in place and making dermal bone and their derivitaves
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What is the structure of primitive dermal bone?
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Enamel coat (hard covering, denticle paint job). Dentine (hard support for enamel). Spongy bone and lamellar bone
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What derivatives of dermal armor do scales have?
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Depending on the type of scale, it can have any combination of all four types (some don’t have all four)
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What derivatives of dermal armor do gnathostome teeth have?
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Enamel and dentin
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Where are dermal cranial bones derived from?
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Dermal armor
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Where are dermal pectoral girdle bones derived from?
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Dermal armor
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Where are dermal pigment cells from?
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Neural crest
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Chromatophores
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cells containing pigment granules
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What are the types of dermal pigment cells?
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Chromatophores, melanophores, xanophores, erythrophores, iridophores.
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Melanophores
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melanin – controls brown and black colors and block others. Controls light penetration
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Xanthophores
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light reflection. Yellow pigments
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Erythrophores
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light reflection. Red pigments
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Iridophores
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light reflection. Contain quinine crystals that reflect and refract light for iridescence
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Is tanning a fast or slow color change?
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Slow
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Is a color change via granules fast or slow?
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Fast
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How does melanin pump around the chromatophore?
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Melanin is pumped into the “pit” and you get clear/white color. Melanin is pumped into the fingers and you get brown/black coloration
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