1. Skin Continued
Region 1
Region 2
Region 3

2. Dermis
Structure
Collagen and elastic fibers located throughout the dermis
Collagen fibers give skin its toughness
Elastic fibers give skin elasticity
Blood vessels

3. 2 Layers of the dermis
1. Papillary layer (upper) made of areolar connective tissue
Upper region (papillary) –
Dermal papillae – projections that increase surface area.
Cause ridges in epidermis: make our fingerprints
Meissner’s corpuscles – touch receptors
Pain receptors
Capillaries (must nourish the epidermis)
Hold epidermis to the dermis

4. 2. Reticular Layer (Deep tissue) Dense irregular connective tissue and Adipose CT
Contains:
Blood vessels
Hair
Pacinian corpuscles: pressure receptors
Oil glands (sebaceous)
Sweat glands and ducts (eccrine and apocrine)
Heat and cold receptors
Phagocytes (phago- eater) immune cells

5. Hypodermis or Subcutaneous layer (Region 3)
Function
Attaches dermis to underlying bone and muscle
Stores body fat (approx. ½ of the body’s fat)
What type of tissue must this be?

6. Appendages of the Skin Exocrine Glands Sebaceous glands
Located by hair root
Produce oil (sebum)
Lubricant for skin (keeps it soft)
Prevents brittle hair
Stops excess evaportion
Cause blackheads and pimples
Gland becomes enlarged because a build up of waste products from the bacteria on the surface of the skin

7. 2. Sweat glands (AKA: Sudoriferous)
Produce sweat
1. Eccrine
Found everywhere but in margin of lips, nail beds, and eardums
Open via duct to pore on skin surface
2. Apocrine
found in armpit, pubic and areola
Ducts empty into hair follicles

8. Sweat Composition
Mostly water, Salts and Urea (nitrogen waste also found in urine)
Function
Helps dissipate excess heat (cools the body)
Excretes waste products
Acidic nature inhibits bacteria growth

9. 3. Hair Produced by hair follicle: sheath surround hair root
Consists of hard keratinized epithelial cells (dead)
Melanocytes provide pigment for hair color
Arrector pili muscle
Smooth muscle (involuntary)
Pulls hairs upright when cold or frightened

10. Accessory Organs - Wax Ceruminous glands
-Specialized apocrine sweat gland
-Located in outer ear canal
-Produces cerumen (wax)
-Secretions provide defense against foreign bodies

11. Accessory Organs - Nails
Scale-like modifications of the epidermis
Heavily keratinized
Stratum basale extends beneath the nail bed
Responsible for growth
Lack of pigment makes them colorless
Function
Grasp and manipulate objects