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