Integumentary System 2 Flashcards
Includes skin, hair, nails, glands; also contains sensory receptors & vascular network
Integumentary System
Functions of the skin
A) Protection
B) Thermoregulation
C) Sensation
D) Excretion
E) Absorption
via blood vessels in skin
Thermoregulation
touch & pressure
Tactile
warmth & coolness
Thermal
Water and some wastes
Excretion
Fat-soluble vitamins, O2, CO2 and some toxins – acetone, lead, mercury and poison ivy & oak
Absorption
Integumentary System
2 distinct layers
Epidermis
Dermis
Thinnest & outermost layer
Epidermis
Composed of keratinized stratified squamous epithelium (30-50 cells thick)
Epidermis
4 specialized cell types
Keratinocytes
2) Melanocytes
3) Langerhans cells
4) Merkel cells
produce keratin
Keratinocytes
produce melanin
Melanocytes
arise from bone marrow and help to activate the immune system
Langerhans cells
associated with sensory neurons to aid in our sense of touch
Merkel cells
deepest
Stratum basale
1 cell layer thick
Stratum basale
Constantly reproducing
Stratum basale
10-25% melanocytes
Stratum basale
Several cell layers thick
Stratum spinosum
Large number of Langerhans cells
Stratum spinosum
3-5 cell layers thick
Stratum granulosum
Keratinization begins
Stratum granulosum
process by which cell’s internal structures die, degrade, and are replaced with keratin
Keratinization
Last layer with blood nutrient supply
Stratum granulosum
only in thick skin
Stratum lucidum
Thin band of flattened cells
Stratum lucidum
20-30 cell layers thick, 3/4 of epidermis
Stratum corneum
outermost
Stratum corneum
Deeper & thicker than epidermis
Dermis
Contains vascular network that “feeds” the epidermis & sensory receptors
Dermis
2 layers
Dermis
Dermis 2 layers
Papillary layer
Reticular layer
flexibility
Areolar connective tissue
extensions into the epidermis
Dermal papillae
Contain blood vessels, free nerve endings (pain) and Meissner’s corpuscles (touch receptors)
Papillary layer (20%)
Dense irregular connective tissue
Reticular layer (80%)
Contains blood vessels, glands, hair follicles, and Pacinian corpuscles (pressure receptors)
Reticular layer (80%)
Has some flexibility but can be torn or damaged
Reticular layer (80%)
Has some flexibility but can be torn or damaged
Scaring/Stretch marks
Blister
composed primarily of adipose tissue
Subcutaneous layer
contains major blood vessels
Subcutaneous layer
Results from a combination of 3 pigments
Skin color
Produced by melanocytes in stratum basale
Melanin
Red to yellow to brown-black
Melanin
Found in plants (carrots)
Carotene