U3: Skin and Body Membranes Flashcards
Cutaneous Membrane (what is it, function 8)
Skin technical term
Provides a protective barrier.
Insulates and cushions.
Prevents loss of moisture.
Reduces harmful effects of UV radiation.
Excretes urea, salts, and water
Synthesizes vitamin D
Manufactures protein needed for immunity
Sensors alert us to external environment
Skin Derivatives
Sweat glands, oil glands, hair, and nails
Outer layer of skin (what is it, made of, has, and blood vessles?)
epidermis
made of stratified squamous epithelium
keratinized (hardened by keratin - fibers protein produced by keratinocytes)
avascular (without blood vessels)
Middle layer of skin (what is it, made of, blood vessels?)
dermis
Dense connective tissue
vasular
Bottom layer of skin
hypodermis or subcutaneous
Anchors skin to underlying organs
Composed mostly of adipose tissue
Serves as a shock absorber
Insulates deeper tissue from extreme temperature changes
Stratum Corneum (CLGSB)
shingle like dead cells filled with keratin
cells held together with proteins
Important barrier that keeps molecules from passing through skin
3/4 of epidermal thickness
Straum Lucidum (CLGSB)
translucent cells that have accumulating keratin
secretes a water-repellant glycoprotein
occurs only in the thick skin where it helps reduce friction
Stratum Granulosum (CLGSB)
Keratin proteins and water-proofing lipids are produced and organized
Stratum Spinosum (CLGSB)
cells change from columnar to polygonal shapes and starts to synthesize keratin
Stratum Basale (CLGSB)
deepest layer
cells undergo mitosis
receive the most nourishment via diffusion from the dermis
Melanin
A yellow, to brown, to black pigment produced by cells called melanocytes
Melanocytes found mostly in the Stratum Basale
Amount depends on genetics and exposure to sunlight
What does sunlight do to melanin?
sunlight exposure stimulates pigment production
too much can damage skin, depress the immune system, and alter your skin
Dermis
made of dense connective tissue
What do the collagen fibers provide?
toughness and attract and bind water to keep the skin hydrated
What do the elastic fibers provide
responsible for elasticity when we are young
What is the upper layer of the dermis
papillary layer
what does the upper layer of the dermis contain
finger-like projections called dermal papillae
pain receptors called free nerve endings
touch receptors called Meissner’s corpuscles
What is the dermis responsible for
fingerprints
What is the deepest layer of the dermis
reticular layer
What does the deepest layer of the dermis contain?
blood vessels
sweat and oil glands
nerve receptors
deep pain receptors called pacinian corouscles
phagocytes
phagocytes
a type of cell within the body capable of engulfing and absorbing bacteria and other small cells and particles.
What are the normal skin color determinants
hemoglobin
melanin
carotene
hemoglobin
red coloring from blood cells in the dermis capillaries
oxygen content determines the extent of red coloring
- well oxygenated -> pink tones
- less oxygenated -> blue tones
Carotene
orange to yellow pigment from some vegetables
Erythma
Redness
fever, embarrassment, hypertension, allergy
Blanching
Pallor (paling of skin)
fever, anger, anemia, low blood pressure
Jaundice
Yellow cast caused
liver disorder
Bruises
hematomas
blood escaped circulation and clotted in tissue spaces
Keratin
protein that helps form hair, nails and your skin’s outer layer (epidermis). It helps support your skin, heal wounds and keep your nails and hair healthy
What do the appendages of the skin do?
all arise from the epidermis and all play a unique roll in maintaining homeostasis
