INTEGUMENTARY SYSTEM Flashcards
largest organ
integumentary system
makes up of integumentary system
skin and its appendages (hair, nails, glands)
largest and heaviest organ comprising of 8% body weight (1.5-2m² in adults)
skin
layers of skin
epidermis, dermis, hypodermis*
functions of skin
- resistance to trauma
- barrier
- thermoregulation
- vitamin d synthesis
- communication
outermost layer of the skin composed of keratinized stratified squamous epithelium and lacks blood vessels
epidermis
cells of epidermis
keratinocytes, melanocytes, merkel cells, langerhans cells
majority of epidermal cells that synthesizes keratin and found at the deeper layer
keratinocytes
found at stratum basale that synthesize brown to black pigment called melanin and shield dna from uv rays
melanocytes
continually shed melanin containing fragments called
melanosomes
associated with sensory nerves or sensations
merkel cells
macrophage-like dendritic cells which are immune defense cells within epidermis
langerhans cells
layers of epidermis from deep to superficial
s. basale
s. spiniosum
s. granulosum
s. lucidum
s. corneum
deepest and youngest layer of epidermis located under dermis where stem cells divide and give rise to keratinocytes that migrate toward the surface and replace lost epidermal cells,
stratum basale / germativum
thickest layer and forms spiny appearance bc of dermosomes that attach keratinocytes tgt making toughness of epidermis
stratum spinosum
3-5 layers of flat keratinocytes containing keratohyalin granules
stratum granulosum
only present in thick skin and is densely packed with keratinocytes containing eleidin, translucent in color
stratum lucidum
oldest layer consisting of dead, scaly, keratinized cells that form a durable surface layer and is resistant to abrasion, penetration, and water loss
stratum corneum
well-supplied with blood vessels, cutaneous glands, and nerve endings, responsible for thermoregulation, hair follicles and nail roots are attached here, and composed of collagen, elastic, reticular
dermis
layers of dermis
dermal papillae and epidermal ridges
upward waves of fingerlike extensions between epidermis and dermis
dermal papillae
downward epidermal waves between the papillae where friction ridges can be seen
epidermal ridges
wavy boundary on fingertips producing fingerprints
friction ridges
2 zones of dermis
papillary layer and reticular layer
loose connective tissue that allows mobility of defense cells and is rich in small blood vessels
papillary layer
dense irregular connective tissue and has thicker bundles of collagen with less ground substance and toughens dermis
reticular layer
difference of thick and thin skin
- presence of stratum lucidum
- reticular layer in thin skin is thicker than thick skin
- thick skin (sweat glands), thin skin (sebaceous glands and hair follicles)
found beneath skin and is known as subcutaneous tissue or superficial fascia with more areolar and mostly made up of fats or adipose tissue, where drugs can be introduced through injection
hypodermis
responsible for skin color
melanin, hemoglobin, carotene
produced by melanocytes and accumulates in keratinocytes of s. basale & spinosum that protects skin from uv rays
melanin
brownish black skin color
eumelanin
reddish yellow sulfur containing pigment
pheomelanin
red pigment of blood
hemoglobin
yellow pigment from egg yolks and can be concentrated to various degrees in stratum corneum, found in palms and soles
carotene
skin markings
friction ridges, flexion ridges, freckles, moles
markings in fingertips for grasping and manipulation of surfaced objects, where fingerprints are seen
friction ridges
where skin folds and lines on flexor surface of digits, palms, wrists, elbows, etc,
flexion ridges / flexion creases