Integument System U5 - Burns & Appendages
Cuticle
-MOST IMPORTANT -formed from overlapping cells & prevent hairs form matting (heavily keratinized)
Cutaneous Sensation
-Meissner's corpuscles -Pacinian receptors -Free nerve endings
Hair papilla
-actively dividing part of hair
Types of Receptors
Meissner's corpuscle Pacinian corpuscle Free nerve endings Krause's end bulbs
Ceruminous glands
modified aprocrine glands, located in external ear canal, secretes cerumen (earwax)
black heads
when a whitehead oxidizes & darkens
Sweat (sudoriferous) glands
- Produce sweat -except nipples & external genitalia - Widely distributed in skin - Two types of sudoriferous glands - Eccrine glands - Apocrine glands -Also include; Ceruminous & Mammary Glands
Eponychium
-(cuticle) overlies root
Blood Reservoir
-5% of blood is kept in skin until needed by other organs/muscles
Thermoregulation
-Sweat helps cool by absorbing heat from body -Subcutaneous fat insulates against heat loss as does hair on scalp
Nail Root
-actively dividing epithelial cells -cells keratinized in region of nail body & spread over nail -Nail bed highly vascularized (pink color, smashed nail)
Hair Bulb
-base of hair follicle & is surrounded by nerve endings -serve as sensory receptors
Terminal Hair
-coarse hair of scalp, eyebrows, pubic areas & chest, face, arms & legs of males after puberty
sebaceous glands
-found all over body (minus soles & palms) -secrete sebum (oil) into the hair follicles where the hair shafts pass through the dermis -lubricates hair & skin -prevents water loss -Holocrine secretions -Stimulated by Androgen Hormones -can be bacterial (kills bacteria)
Acne
-inflammatory disease of the skin involving the sebaceous glands and hair follicles -accompanied by pimples
What are the only hairless areas of the body?
-lips, nipples, external genitalia, thick skinned areas
eccrine sweat glands
-majority of sweat glands -found almost everywhere-Most abundant on palms, soles of feet, & forehead -composed of epidermal cell -Mecrocrine secretions -Secretes sweat- 99% water from blood -controlled by automatic nervous system to prevent overheating of body
Vellus Hair
-pale, fine, covers body in all areas not covered by terminal hair
Excretion
-small amount of nitrogenous waste
Arrector pili muscle
-smooth muscle that causes goose bumps when muscle contracts -pulls follicle into upright position & dimples skins surface when you're cold or scared
Protection
Chemical: low pH of sweat & oil secretions, bacterial sebum, & melanin (UV) Physical: epidermis & its keratinized cells Biological: dermal macrophages & Langerhans' cells in epidermis
Hair & Hair Follicles
Hair in mammals- primarily for warmth Scalp hair- protects from physical trauma, heat loss, sun Eye lashes- keep debris out of eyes Eyebrows- keep sweat out of eyes Nose/ear hair- filter debris & insects Pubic hair- prevent friction during sexual activity
Krause's end bulbs
Pressure and pain receptors
Lamellated corpuscles (Pacinian corpuscles)
deep pressure
Shaft
exits the skin -root is embedded in the skin
Tactile (Meissner's) corpuscle
fine touch and pressure and low- frequency vibration
aprocrine sweat glands
found in armpits, around nipples and groin - axillary & anogenital areas -larger that eccrine glands -secrete products into the hair follicles -bacteria breaks down and causes musky odors -Aprocrine secretions -begin functioning at puberty
Hyonychium
free edge of nail extends over
Free nerve endings
include tickle/ itch
Synthesis of Vitamin D
requires activation of a precursor molecule in the skin by UV rays in sunlight Vitamin D is critical for calcium absorption in digestive tract -activation of steroids -hydrocortisone anti-inflammatory) -activate/deactivate carcinogens that penetrate the epidermis (keratinocytes)
whiteheads
sebum blocked sebaceous glands
Mammary glands
specialized glands that produce milk
Hair (pili)
strands of keratin -hard & tougher; more durable than soft keratin in skin; prevents cell loss from hair
What is alopecia?
thinning hair b/c it sheds more quickly than can be replaced
Appendages of the skin
Sweat (Sudoriferous) glands Sebaceous (oil) glands Hair/Hair Follicles Nails Receptors