BIOL G220: Ch. 5 Flashcards
Terms and concepts from Chapter 5: Integumentary System
integument
skin
integument is the largest _____
organ
layers of integument (2)
epidermis
dermis
what layer is not part of the skin but lies beneath the dermis?
subcutaneous layer (hypodermis)
epidermis
superficial layer of keratinized stratified squamous epithelium,
avascular, any composed of many layers
dermis
deeper layer of areolar and dense irregular connective tissues
subcutaneous layer (hypodermis)
not part of the skin; lies under dermis and is composed of mostly adipose CT as well as areolar CT
functions of integument (7)
- protection
- prevention of water loss
- temperature regulation
- metabolic regulation
- immune defense
- sensory reception
- excretion by means of secretion
epidermal strata (5) from deep to superficial
stratum basale stratum spinosum stratum granulosum stratum lucidum (thick skin only) stratum corneum
stratum basale
single layer of cells capable of mitosis
adjacent to dermis
stratum basale cell types
keratinocytes, melanocytes, tactile cells
keratinocytes in stratum basale
most abundant; produce keratin to protect and waterproof the skin
melanocytes in stratum basale
produce melanin pigment, which absorbs UV light to prevent DNA damage
tactile cells
sensitive to touch
what separates the stratum basale from the connective tissue? (membrane)
basement membrane
stratum spinosum
several layers thick
daughter cells from basale differentiate into nondividing, highly specialized keratinocytes
what type of cells does stratum spinosum have and what is its function?
epidermal dendritic cells (langerhans)
immune cells that fight infection; phagocytes that initiate immune response
stratum granulosum
3-5 layers of keratinocytes
cytoplasm fills with keratin filaments, organelles begin degradation
fully keratinized cells are dead but _____ (stratum granulosum)
strong
extracellular lipids from epidermal ______ _______ (stratum granulosum)
water barrier
stratum lucidum
thin, transclucent, two to three layers thick
present only in thick since (plans of hands, soles of feet)
what are the cells of stratum lucidum filled with? what do they lack?
eleidin: a transparent, intermediate producto f keratin maturation;
lack organelles
stratum corneum
most superficial layer of epidermis
20-30 layers thick dependent on body location
solely dead keratinocytes (sloughed with abrasion)
thick skin
palms of hands and soles of feet
thin skin
lacks stratum lucidum, covers most of body
stratum corneum in thick skin
thick
stratum corneum in thin skin
thin
variations in epidermis pigment caused by…
hemoglobin, melanin, carotene
hemoglobin
blood pigment; red in color
melanin
pigment produced by melanocytes; increases in people exposed to more UV
carotene
yellow-orange pigment from food that builds up in the skin
melanin can be…
donated to neighboring cells by melanocytes
variations in epidermis skin markings include
nevus, hemangioma, friction ridges
nevus
aka mole; localized overgrowth of melanocytes
hemangioma
proliferation of flood vessels that form a benign tumor
friction ridges
folds of epidermis and dermis on fingers, palms, soles, and toes; increase friction for grasping
friction ridges of thick skin
arch, whorl, loop, combination
dermis
deep to epidermis
areolar and dense irregular CT
layers of dermis (2)
papillary
reticular
papillary layer of dermis
superficial; adjacent to epidermis
areolar connective tissue
reticular layer of dermis
deeper and thicker layer
dense irregular CT with large bundles of collagen fibers, blood vessels, glands, hair follicles, and nerves
epidermal ridges and dermal papillae ____ together to keep ___ stuck to dermis. this increases the ____ between the two
lock; epidermis surface area
dermal blood vessels in dermal _____ provide ___ to epidermis
papillae; nutrients
reticular layer of the dermis forms the ______ of the dermis
majority
collagen bundles in reticular layer help connect..
dermis to hypodermis
collagen and elastic fibers are oriented in _____ bundles at specific body locations
parallel
collagen and elastic fibers oriented in parallel bundles function to…
resist routine stresses
lines of cleavage
identify the orientation of the fiber bundles
clinical importantance of lines of cleavage
incisions across these lines heal more slowly than incisions along these lines
striae
form when collagen fibers are town from skin overstretching
wrinkles result from
UV light exposure and aging that reduces flexibility and thickness of the dermis
Nerve fibers are present in the ____
dermis
Functions of nerve fibers in the dermis include… (3)
- tactile (touch) receptors
- control blood flow
- control glandular secretion
tactile receptors (2)
tactile corpuscle (meissner's) paccinian corpuscle
tactile corpuscle
located in dermal papilla to detect fine touch
___ contains blood vessels
dermis
blood vessels in dermis function in (2) ways
- supply nutrients to avascular epidermis
2. important in controlling body temperature
vasoconstriction
narrowing blood vessel diameter; used to shunt blood away from periphery
vasodilation
widening blood vessel diameter; used to move blood toward periphery for releasing heat
subcutaneous layer functions (3)
- protects underlying structures
- stores energy
- insulation
epidermal derivatives
integumentary structures derived from epidermis
(3) epidermal derivatives
- nails
- hair
- exocrine glands of the skin
nails
scalelike modifications of the stratum corneum
nail parts (8)
nail plate nail body nail root nail bed nail matrix lunula eponychium hyponychium
nail plate
whitish free edge
nail body
pinkish (due to dermis underneath)
nail root
covered in skin (beneath the skin)
nail bed
covers a layer of epidermis
epithelial tissue that nail sits on
nail matrix
thickened growing part of the nail bed
lunula
white semilunar proximal area of the nail body caused by thickened underlying stratum basale obscuring capillaries in dermis
eponychium
cuticle
hyponychium
skin around edges of nail
hair
columns of keratinocytes growing from follicles deep in dermis or hypodermis
(3) types of hair
lanugo, vellus, and terminal hair
regions of a hair (deep to surface)
hair bulb, hair root, hair shaft
hair bulb
swelling of epithelial cells where the hair originates
hair root
portion deep to the skin surface
hair shaft
portion extending beyond the skin surface
hair follicle
surrounds each hair
arrector pili
muscles attach to hair shaft that respond to emotions and cold temperatures by contracting, standing the hair up, therefore producing “goose bumps”
follicle has (2) layers creating the hair itself
- connective tissue root sheath (outer)
2. epithelial tissue root sheath (inner)
functions of hair (5)
- protection
- heat retention
- sensory reception
- visual identification
- chemical signal dispersal
exocrine glands of skin (2)
- sweat (sudoriferous) glands
2. sebaceous glands
sudoriferous glands
produce watery solution
merocrine (eccrine) and apocrine
sebaceous glands
produce oily secretions
merocrine
simple coiled tubular glands that release secretions into a duct with a pore on skin’s surface
secretions are 99& water, clear, controlled by NS
numerous ion palms of hands, soles of feet, and forehead
functions of merocrine
thermoregulation
secretion
protection
apocrine
simple coiled tubular glands that secrete into hair follicles at the armpits (axillae), nipples (areola), groin (pubic region), and anus (anal region)
secretions are thick, cloudy, composed of protein and lipids and bacterial growth causes distinct odor in these regions
Beep Boop
I love you
between the two sudoriferous glands, ____ has the smaller lumen, while ___ has the larger
merocrine; apocrine
sebaceous glands
secrete oily sebum into hair follicles or directly onto kin surface
functions of sebaceous glands
lubrication; preventing drying of hair and skin
supports microbiome
Sebaceous glands are relatively ___ during childhood. Sex hormones at puberty cause secretions to _____ significantly
inactive; increase
