Integumentary System Flashcards
primary role of the integument
protection
protects the internal organs from mechanical injury
Dermal armors
secrete slimy or noxious substances
Glands
provide protective coloration
Serves as barrier to the rays of the sun
Pigments
Exteroceptive Role of the integument
Protective in its most primitive state
Naked nerve endings are stimulated when foreign objects contact the skin
The only role of cutaneous receptors in agnathans
More complex receptors are found in other fishes and tetrapods and highly used for survival
Some Roles of the Integument
Protective Role
Exteroceptive Role of the integument
Respiration
Excretion
Thermoregulation
Locomotion
Maintenance of Homeostasis
Nourishment
Pheromones
Skin Coloration
Roles of the Integument
Naked nerve endings are stimulated when foreign objects contact the skin
The only role of cutaneous receptors in agnathans
More complex receptors are found in other fishes and tetrapods and highly used for survival
Exteroceptive Role of the integument
Roles of the Integument
Supplements gills and lungs of many amphibians (aquatic urodeles)
Respiration
Scales and cornified epithelium are not conducive for cutaneous respiration
true
_____________ rely its respiration entirely on the skin (they don’t have gills or lungs)
Plethodontid salamander
Roles of the Integument
CO2 excretion in some aquatic amphibians
Sweat glands are supplementary to excrete nitrogenous wastes
Ammonia in fishes is easily diffused via gill epithelium and other tissues exposed to water
Excretion
Roles of the Integument
Function of the skin of endotherms (birds and mammals)
Fur and feather insulate against cold
Sweat cools by evaporation
Thermoregulation
Dilation of blood vessels within the dermis heat loss by radiation
increases
Roles of the Integument
Performed by adhesive pads, claws that assist in climbing, scutes that assist in slithering and feathers that provide airfoil
Webbed feet for those that wade in water
Webbed wings in bats enable them to fly
Locomotion
Roles of the Integument
Reservoirs of calcium and phosphate molecules in fishes
Cornified epithelium of tetrapods conserve water
Absorbs water under the influence of posterior pituitary gland in aestivating lungfishes, toads and other craniates
Maintenance of Homeostasis
Roles of the Integument
Mucus secreted in some teleosts provide nutrition to hatchlings
Mammary glands provide nourishment to the young
Maintenance of Homeostasis
Roles of the Integument
Serves as species identification or serves as alarm
Elaborate colorations help during breeding season
Can be used as protection
Pheromones and Skin Coloration
Forms the interface between the animal’s internal environment and the outside world
Integument
Contains epithelial, connective adipose and smooth muscle tissues
Also contains blood vessels, glands, sensory receptors, nerves and other structures
Integument
Superficial part of skin; stratified squamous epithelium; composed of four or five strata
Barrier that prevents water loss and the entry of chemicals and microorganisms; protects against abrasion and ultraviolet light; produces vitamin D; gives rise to hair, nails, and glands
Epidermis
Most superficial strata of the epidermis; 25 or more layers of dead squamous cells
Provision of structural strength by keratin and protein
envelope within cells; prevention of water loss by lipids surrounding cells; sloughing off of most superficial cells resists abrasion
Stratum corneum
Three to five layers of dead cells; appears transparent; present in thick skin, absent in most thin skin
Dispersion of keratohyalin around keratin fibers
Stratum lucidum
Two to five layers of flattened, diamond-shaped cells
Production of keratohyalin granules; lamellar bodies release lipids from cells; cells die
Stratum granulosum
A total of 8 to 10 layers of many-sided cells
Production of keratin fibers; formation of lamellar bodies
Stratum spinosum
Deepest strata of the epidermis; single layer of cuboidal or columnar cells; basement membrane of the epidermis attaches to the dermis
Production of cells of the most superficial strata; melanocytes produce and contribute melanin, which protects against ultraviolet light
Stratum basale
Deep part of skin; connective tissue composed of two layers
Responsible for the structural strength and flexibility of the skin; the epidermis exchanges gases, nutrients, and waste products with blood vessels in the _______
Dermis
Papillae project toward the epidermis; loose connective tissue
Brings blood vessels close to the epidermis; dermal papillae form fingerprints and footprints
Papillary layer
Not part of the skin; loose connective tissue with abundant fat deposits
Attaches the dermis to underlying structures; fat tissue provides energy storage, insulation, and padding: blood vessels and nerves from the subcutaneous tissue supply the dermis
Subcutaneous tissue
Composed of a stratified epithelium which developed from embryonic ectoderm
Epidermis
consists of 1 to 2 mitotically active, cuboidal cell layers located above the basement membrane
Cells move toward the body surface to differentiate and are eventually sloughed off
Stratum germinativum
Mat of collagen and elastin fibers; dense irregular connective tissue
Main fibrous layer of the dermis; strong in many directions; forms cleavage lines
Reticular layer
Composed of a stratified epithelium which developed from embryonic ectoderm
Epidermis
Some epidermal cells synthesize _________ which is a water-insoluble, horny protein that may fill the cells and replace other organelles
kertain
animals that have a thin layer of epidermis
Fishes and amphibians
Epidermis Two types of covering:
Aquatic craniates -
Terrestrial craniates - water-impervious cornified cells
animals that have a thick layer of epidermis
Reptiles and mammals
which is a water-insoluble, horny protein that may fill the cells and replace other organelles
stratum corneum
Epidermis covering that has a thin coat of mucus
Aquatic craniates
Epidermis covering that is mostly multicellular
Terrestrial craniates
Develops from mesenchymal cells which are mostly derived from mesodermal dermatome of somites
Dermis
Basic component is collagen and elastic fibers embedded in proteoglycans and other macromolecules which holds other component in place and provide tensile strength
Dermis
Other components of dermis
blood vessels, small nerves and pigment cells
Lymphatics
Naked and encapsulated exteroceptors
Bases of multicellular glands
Bases of hairs or feathers and their erector muscles
is thicker than the epidermis in mature skin and consists of two layers:
Irregularly arranged collagen fibers
Dermis
Dermis consists of two layers:
Stratum laxum
Stratum compactum
Teeth, bony and horny scales, feathers and hair develop as a result of intricate interactions between the dermis and epidermis via neural crest cell migration
Skin Derivatives
Glands, feathers, hair and other keratinized structures are composed of __________ in which some parts invade the underlying dermis
epidermal cells
Superficial bones are dermal derivatives
true
Teeth and bony scales are of ______ and _____
epidermal and dermal products
These structures have supportive and protective functions that they are sometimes termed as
integumentary skeleton
Cells that contain pigments found in all vertebrates except albinos
Develop from neural crests and are located in the upper part of the dermis in fishes, amphibians and reptiles
They penetrate and are located in the epidermis of birds and mammals
Chromatophores
Star-shaped cells containing melanin
With long, branching processes
granules may either be black, brown or more yellow and reddish
Melanophores
Melanophores contained within cellular organelles called
melanosomes
is synthesized within melanophores of birds and mammals but most of it is transferred to feather, hair and other epidermal derivatives
Melanin
in anamniotes and reptiles may migrate into processes of the melanophores, maximizing the color or concentrating it
Melanosomes
Contain crystalline chemochromes from guanine
Generate iridescent colors because of the diffraction of light within the stacked plates
Iridophores or guanophores
Utilize crystalline purines (often guanine) to reflect light
Produce reflective white hues
Leucophores
Contain yellow pigments composed of pteridines
Xanthophores
Contain reddish pigments composed of carotenoids
Erythrophores