THE DERMIS Pages

 Dense connective tissue of varying thickness  Two layers: ◦ Papillary (upper) ◦ Reticular (lower)

 Uneven  Peg-like projections called dermal papillae lie at the dermal-epidermal junction ◦ This layer provides nutrients to the epidermis ◦ Houses pain and touch receptors ◦ Forms fingerprints (on hands and feet):  increases friction and gripping  sweat pores leave identifying “sweat films”  patterns are genetically determined © 2015 Pearson Education, Inc.

 Deepest skin layer; makes up 80% of dermis  Collagen and elastic fibers provide strength and elasticity ◦ This is the layer that looses elasticity = WRINKLES!  Contains blood vessels, sweat and oil glands  Lamellar corpuscles- sense deep pressure © 2015 Pearson Education, Inc.

Epidermis Dermis Papillary layer Reticular layer

Dermal papillae Hair shaft Pore Appendages of skin Eccrine sweat gland Arrector pili muscle Sebaceous (oil) gland Hair follicle Hair root Cutaneous vascular plexus Adipose tissue Epidermis Dermis Papillary layer Reticular layer Hypodermis (subcutaneous tissue) Nervous structures Sensory nerve fiber Lamellar corpuscle Hair follicle receptor (root hair plexus)

 Three pigments contribute to skin color: 1.Melanin  Yellow, reddish brown, or black pigments 2.Carotene  Orange-yellow pigment (deposited in the skin) 3.Hemoglobin  Red coloring from blood cells in dermal capillaries  Oxygen content determines the extent of red coloring  Lighter skin shows this more so than darker © 2015 Pearson Education, Inc.

 Redness (erythema)—due to embarrassment, inflammation, hypertension, fever, or allergy  Pallor (blanching)—due to emotional stress (such as fear), anemia, low blood pressure, impaired blood flow to an area  Jaundice (yellowing)—liver disorders create excess bile deposition in tissues  Bruises (black and blue marks)—hematomas (blood clots) © 2015 Pearson Education, Inc.