Chapter 6 Flashcards
Integumentary system
integument
skin that covers the body; cutaneous membrane
layers of integument (2)
epidermis and dermis
five strata of epidermis
stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum
layers of cells in each strata? (no specific number, just rough estimates)
basale - one
spinosum - more than one
granulosum - 3-5 layers
lucidum - 2-3 layers (few)
corneum - up to hundreds of layers
“basement” layer, single layer of cuboidal cells
stratum basale
what kind of cells are in the basal layer? (4)
keratinocytes, melanocytes, tactile/merkel cells, stem cells
most abundant cell in epidermis
keratinocytes
what do melanocytes do?
produce/store melanin
“spiny” layer, several layers of keratinocytes, contains dendritic cells
spinosum
function of dendritic cells?
immune functions
“granular” layer, beginning of keratinization, 3-5 layers of keratinocytes
granulosum
“clear” layer, 2-3 layers of flat keratinocytes, only found in thick skin
lucidum
“hornlike” layer, most superficial layer of epidermis, 20-30 layers of keratinocytes
corneum
how can you tell a cell is keratinized?
cell death; cell without a nucleus
thick skin
has all 5 layers and sweat glands, lacks hair follicles and sebaceous glands
where is thick skin found?
on the palms of hands and feet
thin skin
has 4 layers only; lacks stratum lucidum, has sweat glands + hair follicles + sebaceous glands
where is thin skin found?
on most of the body
what type of tissue makes the dermis?
connective
two layers of the dermis
papillary and reticular
(papillary is superficial, reticular is deep)
what connective tissue makes the papillary layer?
areolar
what connective tissue makes the reticular layer?
dense irregular
what structure is found in the papillary layer?
dermal papillae
what structure(s) are found in the reticular layer?
many; collagen fibers in many directions, hair follicles, sebaceous + sweat glands, nerves and blood vessels
cleavage lines
collagen and elastic fibers in skin organized in regions; orient in the direction of stress
subcutaneous layer
hypodermis; not part of integument, thickness is influenced by hormones
function of subcutaneous layer?
binds skin to underlying structures, provides padding and insulation, energy/lipid storage
what connective tissue composes the subcutaneous layer?
areolar and adipose
function of integument
protection; physical barrier and protects from UV radiation and harmful chemicals toxins, microbes, etc
precursor of vitamin D that sits in the skin
7-dehydrocholesterol
what is needed to synthesize vitamin D?
integument, liver, kidney
what turns the precursor into vitamin D3?
keratinocytes
where does vitamin D3 go to convert to calcidiol?
into the blood, then to the liver
how does cacidiol turn into active vitamin D?
calcidiol is transported to kidneys where it turns into calcitriol (active vD)
true or false; the integument is selectively permeable, meaning that anything small or nonpolar can be absorbed
true
vasoconstriction
vessels diameter decreases; less blood transported through vessel; blood is pulled away from surface to conserve heat
vasodilation
vessels diameter dilates; more blood transported; blood is closer to body
nail matrix
proximal end of nail body; active site of growth
lunula
proximal end where stratum basale is thicker and appears white
eponychium
the cuticle of the nail
