B) DERMIS (Pg. 117 – 119) The 2nd Major Skin Layer. The DERMIS is composed of Dense irregular C.T. which is both strong and flexible. “Embedded” within the C.T. of this layer, you will find blood vessels, nerves, (hot, cold, pressure, pain), hair follicles, sweat glands, sebaceous (OIL) glands, etc.

The thickness of the dermis may vary in different body regions (i. e The thickness of the dermis may vary in different body regions (i.e. it is THICK on the soles of the feet, but THIN on the eyelids.) The dermis has 2 Major Layers: Finger part or Papillary layer = top 1/3 Reticular layer = bottom 2/3

Papillary Layer – is the top 1/3 of the dermis, directly under the epidermis. Small “projections” from the bottom layer “stick up” into the epidermis, forming the DERMAL PAPILLAE. Examples of Papillae: fingerprints, bumps on the tongue, etc.

Blood vessels / capillary beds will often move all the way up into the papillae as well as nerve endings. The epidermis is forced to grow over this folded level, causing fingerprints, toe-prints, etc. This makes it easier to “grip” things.

2) Reticular Layer: is the bottom 2/3 of the dermis 2) Reticular Layer: is the bottom 2/3 of the dermis. This layer of dense irregular C.T. contains sweat glands, sebaceous glands, hair follicles, etc.

C) HYPODERMIS The 3rd Major Skin Layer. The HYPODERMIS is also called the Subcutaneous Layer. It is composed of ADIPOSE tissue (aka FAT.) This provides insulation, cushioning, and energy storage. Thicker in women than men.

D) SKIN COLOR – is a result of 3 different pigments. 1) MELANIN – depending upon concentration, this pigment can run from dark brown to light yellow. Freckles and Moles are localized concentrations of Melanin. This pigment is made by MELANOCYTES in the S. Basale to protect the underlying organs from the harmful UV radiation found in sunlight. (Darker skin = nearer Equator.)

2) CAROTENE – is a yellow/orange pigment (found in carrots) that is used when several cell parts are made. In the absence of Melanin, it will cause the S. Corneum to have a slightly yellow color. This is usually more obvious in the soles/palms. Genetically, this tends to be more concentrated in the Oriental races. 3) HEMOGLOBIN – Because the Epidermis is transparent, if Melanin/Carotene are NOT present, the skin will have a slightly pink tone. This color comes from red HEMOGLOBIN in the blood of Dermal Capillaries.

ALBINO (ALBINISM) Definition: Albinism or an albino is a person that has no MELANIN in the skin. This creates a person with white hair, white eyelashes, blue eyes and pale white skin. It is caused by a recessive gene that is carried by both parents.