Flashcards in Integument Deck (75)
List 5 epidermal derivatives
foot pads, claws, hooves, horns (but not antlers), anal sacs/glands, mammary glands, uropygial glands, wattles, spurs, feathers
protection, prevent water loss, temperature regulation, sensation, immune functino, excretion, water-ion balance (sweating), calcium homeostasis, energy storage
functions of hair
insulation, camouflage, social display, sensory, protection
what are the 3 layers of the skin?
epidermis, dermis, and hypodermis
epidermis is made of
stratified squamous keratinized epithelium
what are the two layers of dermis
papillary and reticular layers
hypoddrmis/subcutis is sometimes rich in what? What does the hypodermis attach to?
-rich in adipocytes
-attaches loosely to organs
what layer of skin is thick skin? what are some other characteristics of thick skin?
-hairless, merocrine sweat glands present, ie. digital pads, muzzles
what layer is thin skin? name some characteristics
thin skin is part of the epidermis
-hair follicles with arrector pili muscles, sebaceous and sweat glands
[thick vs thin skin picture]
[epidermal pegs picture] what are the names of these structure, and where is it found?
1. epidermal pegs: downward projections of epidermis into the underlying dermis
2. dermal papillae: upward projections from dermis
-footpad, nasal planum, scrotum; found at areas subject to traction stress
dermal papillae function
increase area of contact between dermis and epidermis
-bring blood vessels near epithelium
what is the main component of dermis?
Papillary layer: what type of connective tissue is it made of? What type of ollagen? What other chatacteristics does it possess?
-type 1 and 3 collagen
-mast cells, macrophages, vessels, and nerves
[insert picture of papillary and reticular layers]
Reticular layer: type of connective tissue, type of collagen, and other characteristics
-dense irregular ct
-type 1 collagen
-network of elastic fibers, blood vessels, and nerves
skin elasticity refers to what in the dermis?
the network of elastic fibers present in the reticular layer [insert skin elasticity picture]
cells of the epidermis can fall into one of two categories:
keratinocytes or non-keratinocytes
most common cell type of the epidermis: they make up 95% of the epidermis
-langerhans cells - part of immune system
-merkel's cells - sensory cells
-melanocytes - protective
adhere cells of the epidermis include
desmosomes between cells and hemidesmosomes attaching to the basal lamina
epidermal layers are constantly replacing...
cytoplasm with keratin, to continually add to the outer layer
layers of the epidermis include [picture of layers of epidermis]
[picture of stratum basale]
-single layer of cuboidal-columnar cells
-rests on basal lamina, possesses hemidesmosomes and desmosomes
-melanocytes may be present
[picture of adhere cells]
1. adherens junctions
2. keratin filaments
stratum basale function
-mitotic division allows new cells to move up to keratinize on upper layers
[pictures of stratum spinosum]
-what is this layer called and what are its characteristics?
-cuboidal or slightly flattened
-in thin skin there are 1-2 layers, in thick there are many
-desmosomes give spiny appearance (aka prickle cells layer)
-cohesive cells that resist abrasion
-layer retains some mitotic capability if needed
[pictures of desmosomes]
what are these structures?
-3-5 thin layers, may be hard to see
-possesses keratohyalin granuales
-no mitotic activity; it is the last living layer, last to have nucleus and organelles
-has lamellar gramules
-secreted by cells to form waterproof lipid sheets aka intercellular cement