Epithelium and integument Flashcards
What is integument
Includes the skin coverings surface of body and specialized derivatives
Types of integument
nails, claws, & beaks
– feathers, scales, & hair
– sebaceous, sweat, & other glands
List several functions of integument (8)
– Protection of underlying tissues
– Reception of tactile, thermal, or pain stimuli
– Prevent desiccation
– Respiration (mainly in amphibians)
– Provides insulation (hair, feathers, adipose tissue)
– Can increase heat loss by changes in hair or feather position or by increased evaporative water loss (sweating)
– Removal of excess water and salts
– Production of vitamin D
What are the two main layers of integument
Epidermis, dermis
what is the epidermis and what is it made of
Upper layer (ectodermal origin) of specialized epithelium
what is the epidermis in the embryo
periderm
Epithelial tissues have a ___ surface and an ___ surface, found ___ the body, NOT ___ to integument
free, attached, throughout, restricted
Basement membrane anchors ___ to ___ via ___ tissue fibers. Composed of ___ and ___ lamina.
epidermis, dermis, connective, basal (epi), reticular (derm)
Features of epidermis
simple or stratified?
Keratinized?
thick or thin?
does it have a mucous cuticle?
Can be simple or stratified, keratinized or non-keratinized, thick or thin, may have mucous cuticle
what is the dermis
Dense connective tissue layer (mesodermal origin) deep to the epidermis, with sensory endings (tactile, thermal, pain)
what is the dermis made of
Composed of stratum laxum and stratum compactum
the dermis rests upon the ___ (___ origin) of ___ and other connective tissue. If thick, hypodermis is termed ___
hypodermis, mesodermal, adipose, superficial fascia
Hypodermis rests upon ___ (___ origin).
muscle, mesodermal
epidermis evolvement
ectoderm, periderm, epidermis
three features of epithelia
cell shape, cell laying, surface specializations
what are the three cell shapes and describe them
Squamous – very flat cells, width greater than height
– Cuboidal – height and width approximately equal
– Columnar – cell height greater than width
four types of cell layering
simple, stratified, transitional epithelium, pseudostratified
what is simple cell layering
single layer of cells on the basement membrane
what is stratified cell layering
two+ layers of cells stacked on each other, only basal layer touches basement membrane. Shape of apical layer determines the “shape” designation (most basal layers are cuboidal
what is transitional epithelium cell layering
a specialized type of stratified cuboidal found in the urinary system, appears stratified squamous when stretched
what is pseudostratified cell layering
simple epithelium gives the illusion of being stratified – all cells sit on the basement membrane, nuclei of cells are at various levels
what are the surface specializations
Cilia (motile), microvilli (increase surface area), & stereocilia (neuro/secretion)
describe structure of epidermis in amphioxus
simple columnar or simple
cuboidal
describe structure of epidermis in lamprey
stratified cuboidal
describe structure of epidermis in scaled fish
stratified cuboidal
or stratified squamous
describe structure of epidermis in amphibian
very thinly keratinized stratified
squamous
describe structure of epidermis in reptiles
keratinized stratified squamous
describe structure of epidermis in birds
keratinized stratified squamous
describe structure of epidermis in mammals
keratinized stratified squamous
Keratin is at type of intermediate
___, keratinized cells ___ at
maturity
filament, dead
what gets keratinized
stratum corneum of epidermis
can keratinization level vary in an animal
Keratinization level can vary by region within an animal:
Thick and Thin Skin (Human)
what is the bulk of the hypodermis
adipose connective tissue
what is the bulk of the upper epidermis
areolar connective tissue
what is the bulk of dermis
dense connective tissue
what are the two dermal layers
stratum laxum (spongioso, spongiosum), or stratum compactum
where is the stratum laxum and describe it
where is it
descirbe the connective tissue
what layer is it in mammals
is it vascualr
Upper layer deep to the basement membrane, loosely packed
connective tissue (papillary layer in mammals), is vascular
what is special about fish and stratum laxum
in fish, scales may be presen
what is special about stratum laxum and chromatophores
Chromatophores (pigment producing cells) from neural crest tissue
typically reside here (rarely in epidermis), but pigments may be
transferred to epidermis
where is the stratum compactum and describe it
where
what tissue
what layer in mammals
is it vascualr
Deep to stratum laxum, composed of dense connective tissue,
(reticular layer in mammals), is vascular
where is the hypodermis and describe it
where
what tissue is it made of 2x
what corpuscles
and is it vasucalr
deep to dermis, composed mainly of adipose tissue,
may contain connective tissue septa, nerves and sensory corpuscles,
is vascular
Note – epidermis is ___ in most vertebrates (exceptions),
dermis brings ___ in close contact to epidermis
avascular, blood vessels
in fish skin scales are of
___ origin, but are
found at the interface
between the ___
and ___
dermal, epidermis, dermis
do endocrine glands have ducts
no
do exocrine glands have ducts
yes
do uni-cellular glands exist
yes
3 exocrine glands and where are they located
merocrine (eccrine), apocrine, holocrine: epidermis
merocrine glands what do they do
ecretory products packaged into vesicles, fuse with membrane
to secrete product into lumen of gland by exocytosis
types of merocrine gland
Most common type of exocrine gland. Mucous, Serous, and
Mixed types
examples of merocrine glands
eccrine sweat glands are merocrine/eccrine glands
describe apocrine
No vesicles, products and apical portion of the cell (including
plasma membrane) is pinched off as the secretion
ex of apocrine gland
Mammary glands are apocrine gland
describe holocrine glands
Apical cells fill with the product before the entire cell dies and is
released. Cell disintegrates, releasing product
ex of holocrine gland
Meibromian (tarsal) gland of the eye and sebaceous glands are
holocrine glands
Describe mucous glands, including secretion, nuclei, cytoplasm, and what is prominent about it
Secrete viscous highly glycosylated glycoproteins. Nuclei are flat and
found near basement membrane. Cytoplasm stains lightly. More
prominent lumen than serous glands
describe serous glands, including what they secrete, ex, what is secretory unit shape, nuclei, and cell shape
Secrete watery enzyme-rich products, (digestive enzymes produced
by the pancreas and salivary glands). Secretory unit is usually alveolar
or acinar shape. Nuclei are rounded or oval, cell are basophilic when
stained (blue) due to abundant RNA in cytoplasm for protein synthesis
describe mixed glands, including what they contain
Either have mix of mucous and serous cells within an secretory end
piece, or a mix of mucous and serous end pieces with in a compound
gland
describe a feature of mucous cells and their lumen
Mucous Glands have moderately large lumen generally filled with
secretion.
shape of serous glands
Serous glands are rounded to pear-shaped alveoli (acinar) – cells
pyramidal; around small lumen
feature of mixed sero-mucous cells
has tubules
Non-Mammalian Vertebrate Skin Glands
mucous and poison glands, femoral glands, uropygial glands
describe mucous and poison glands
who has then
purpose of both
Found in fish and amphibians
– Mucous glands aid in keeping skin moist, important for cutaneous
respiration
– Poison glands produce noxious substances as defense mechanisms
against predators
describe femoral glands
who has them
where are they
purpose
Found in reptiles
– Located on underside of thigh in male lizards, opens through short duct
passing through a spike-like projections, presumed function in
attraction of mates
uropygial glands
who has them
where
what do they do
what do they contain
Preening glands of birds
– Only integumentary glands in birds, located at the base of tail on dorsal
side. Are compound glands with secretions containing oils and wax
(lipids), waterproofs feathers and functions in beak and feather
maintenance
