THE DERMIS Pages

 Dermis is made of dense connective tissue  Varies in thickness throughout the body  Has two layers: ◦ Papillary ◦ Reticular

 Uneven  Contains projections called dermal papillae ◦ contain capillary loops that furnish nutrients to the epidermis ◦ houses pain receptors (free nerve endings) and touch receptors ◦ On hands and feet forms fingerprints:  Definite patterns that increase friction and gripping  Sweat pores leave identifying “sweat films”  Patterns are genetically determined © 2015 Pearson Education, Inc.

 Makes up 80% of dermis  Collagen and elastic fibers ◦ Strength ◦ Elasticity  Blood vessels maintain body temperature  Sweat and oil glands  Lamellar corpuscles- sensory receptors ◦ Send sensory information about deep pressure  (Remember the Merkel cells are responsible for light pressure and are found in the epiderm-derm jx) © 2015 Pearson Education, Inc.

Epidermis Dermis Papillary layer Reticular layer

 Three pigments contribute to skin color: 1.Melanin  Yellow, reddish brown, or black pigments 2.Carotene  Orange-yellow pigment from some vegetables 3.Hemoglobin  Red coloring from blood cells in dermal capillaries  Oxygen content determines the extent of red coloring © 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 disorder  Bruises (black and blue marks)—hematomas (blood clots) © 2015 Pearson Education, Inc.

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)