Ch. 6 Integumentary System Flashcards
Integumentary system components (7)
Skin Accessory organs: - sweat glands - subcutaneous glands - hair - hair follicles - sensory receptors - nails
Skin functions (6)
- two-way barrier: protects against invasion from pathogens, ultraviolet light damage, loss of body fluids, and physical trauma
- regulates body temperature: blood vessels release excess heat and conserve heat (adipose tissue is thermal insulation)
- sensory information: provided by sensory receptors in skin to the brain
- excretes waste products: salts, water, and organic molecules
- synthesizes vitamin D: important for calcium metabolism
- stores energy: hypodermis in adipose tissue
Two layers of the skin
- superficial epidermis
- deeper dermis
Epidermis (4)
- superficial layer
- stratified squamous keratinized epithelial
- avascular
- 5 layers of thick skin, 4 layers of thin skin
Dermis (5)
- deep layer
- connective tissue
- highly vascular
- 2 layers
- glands, hair, and sensory receptors
Hypodermis (3)
- deep to dermis
- adipose tissue
- subcutaneous layer
Epidermis layers (5)
- stratum corneum
- stratum lucidum
- stratum granulosum
- stratum spinosum
- stratum basale (germinativum)
Keratinocyte (3)
- found in all epidermal layers
- most abundant skin cell
- produce keratin
Stratum corneum (3)
- most superficial layer
- 25-30 rows
- dead keratinocytes
Stratum lucidum (2)
- found in thick skin of palms and soles
- 3-5 layers of dead keratinocytes
Stratum granulosum (2)
- 3-5 layers flattened keratinocytes that are dying and shrinking
- becoming filled with keratin
Stratum spinosum (2)
- 8-10 layers of keratinocytes
- “spiny” shape
Stratum basale (germinativum) (3)
- deepest layer
- touches basement membrane
- single layer, actively dividing cells
Langerhan’s cell (3)
- stratum spinosum
- migrate from bone marrow
- protect against bacteria
Merkel cel (2)
- stratum basale
- touch receptor
Melanocyte (4)
- stratum basale
- cell extensions grow into stratum spinosum
- produce melanin
- dark pigment, gives skin and hair its color
Papillary region (3)
- upper part of the dermis
- thin region of loose connective tissue
- dermal papillae: form ridges and whorls in fingers, palms, toes, and soles (finger-like ridges poking toward epidermis)
Reticular region (3)
- deep part of dermis
- dense irregular connective tissue
- collagen fibers, elastic fibers, and blood vessels
Sebaceous glands (2)
produce oily product, sebum (deposited in ducts that empty in hair follicle)
- found in hair follicles
Sweat glands (3)
- located deep in dermis
- produce watery material
- two types: eccrine glands and apocrine glands
Merocrine (eccrine) glands (3)
- widely distributed
- produce watery perspiration to regulate body temperature
- product empty onto skin surfaces through pores
Aprocine glands (2)
- produce thickened secretion and secrete onto hair follicle
- axillary and genital regions
Sensory receptors (4)
- endings of sensory neurons
- generate electrochemical signal when they sense change in environment (temperature, pressure, or fine touch)
- Meissner’s corpuscles
- Pacinian corpuscles
Meissner’s corpuscles (4)
- sensory receptor
- papillary region of dermis
- sensitive to fine touch
- rod-shaped swellings at end of sensory neurons
Pacinian corpuscles (3)
- reticular region of dermis
- sensitive to pressure
- round swellings with multiple rings of protein fibers (sliced onion)
Shaft
part of the hair projecting from skin surface
Root
submerged portion of hair
Hair follicle (2)
- surrounds root
- sheath of epithelium extending downward into dermis
Arrector pili muscle
band of smooth muscle
Hair bulb (3)
- base of hair follicle
- swelling of germinal epithelial cells
- new cells produced here
Matrix cells (4)
- cluster of cells
- push upward from growth area
- die and become keratinized
- receive nourishment from blood vessels
