Skin Color Due to: 1. Pigment composition (melanin, carotene, and hemoglobin) and concentration (how much) 2. Dermal blood supply Skin Color: – Skin comes in different colors!! – Distribution of skin color is not random! – Darker skinned people live near the equator (need more protection from the sun) – Lighter skinned people live near the poles

Skin Color - Pigments Melanin – Color  Yellow  reddish brown  black – No matter how dark or light skinned a person is, they have about the same number of melanocytes!!

Albinism Mutant gene that makes melanin is inherited   Vitiligo 

Jaundice Most often seen in newborns  Caused by blood incompatibility or immature liver  Cured by: 

Skin Color - Pigments Carotene = Orange-yellow pigment Located: 1) 2) 3) Can be converted to vitamin A – Required for: Normal maintenance of epithelia Synthesis of photoreceptor for pigments in the eye

Skin Color – Pigments Blood  contains pigment hemoglobin – Binds and transports oxygen – When oxygen is bound  – When oxygen isn’t bound  Most apparent in lightly pigmented individuals – Lots of blood flow (inflammation)  bright red – When circulation is reduced  pale – Sustained reduction in circulation  very dark red (blue/purple) – Because Caucasian skin contains only small amounts of melanin, the epidermis is nearly transparent and allows hemoglobin’s color to show through

Epidermis and Vitamin D 3 Limited sun exposure is very beneficial!! Epidermal cells exposed to UV radiation – Vitamin D 3 is converted into calcitriol which is necessary for calcium and phosphorus absorption in the small intestine. – An inadequate supply of calcitriol leads to impaired bone maintenance and growth.

The Hypodermis Aka. Subcutaneous or superficial fascia Composed of Adipose Not really a part of the integument, but it is important in stabilizing the position of the skin in relation to underlying tissue Reduces heat loss, acts as an energy reserve, shock absorber Men accumulate – neck, arms, lower back, stomach, and butt Women accumulate – breasts, butt, hips, and thighs.

Integument Appendages Sweat glands – Sudoriferous glands Oil glands – Sebaceous glands Hair Nails

Sweat Glands - Sudoriferous APOCRINE Located  axillary and groin regions Ducts are larger than eccrine Ducts empty into hair follicles Is thicker than regular sweat – also contains fat Secretion odorless  bacteria decomposes the fat  odor Start to function at puberty No role in temperature regulation

Sweat Glands - Ceruminous Modified sweat gland Makes cerumen Ear wax Function – Traps foreign particles or small insects and keeps them from reaching the eardrum

Sebaceous Glands (OIL) Found everywhere except on palms of hands and soles of feet. Large on face, neck, and upper chest Small everywhere else Secretes sebum – lubricates the hair and skin – Prevents hair from becoming brittle – Slows water loss – Bactericidal action

Hair Seen almost everywhere on the body About 5 million! Made up of hard keratin – Tougher and more durable – Individual cells don’t flake

Hair - Types Vellus – “peach fuzz” – Short, fine, lightly colored – Located over much of the body Terminal – Thick, long, more deeply pigmented, sometimes curly – Located on head, eyebrows, and eyelashes, arm pits, groin