1. STRUCTURES OF THE SKIN
HCT I

2. Layers of The Skin Two primary layers Epidemis Dermis
Subcutaneous Tissue- A layer of loose connective tissue and fat that supports the epidermis and dermis.
Insulates the body
Stored source of energy
Shock absorbing pad

3. Epidermis
The outermost and thinnest primary layer of skin. Cells are arranged in distinct layers
Thickness varies on the body.
Thinnest on the eyelids
Thickest on the palms and soles of the feet.
Stratum Germinativum- innermost layer where cells divide and push already formed cells to the surface.
WHY IS CELL REGENERATION IMPORTANT?
Maintaining the skin barrier helps to defend against infection even with injuries.

4. Epidermis
Keratin- a tough waterproof protein that replaces a cells cytoplasm as they approach the surface
Provides the outmost layer of skin with abrasion-resistance and protective qualities.
Stratum Corneum- Outmost layer of keratin filled cells, made up of dead flat skin cells that shed every couple of weeks.
DO YOU KNOW WHAT MOST DUST IS MADE OF?

5. EPIDERMIS
PIGMENT CONTAINING LAYER- epidermal layer that contains pigments called:
MELANOCYTES ,(a specialized epidermal cell) which produces a brown pigment called melanin
Amount of melanin depends on genetics
Increased melanin= increased skin color
Sunlight can increase the amount of melanin produced.

6. EPIDERMIS
Dermal Epidermal Junction-the area between the epidermis and dermis.
Break down of this junction can lead to blisters.
Burns
Friction
Exposure to irritants (poison ivy)

7. Dermis Deeper and thicker layer of primary skin layers
Composed largely of connective tissue
Dermal papillae-(upper layer)
Important part of the dermal epidermal junction helping to keep the skin layers together
Form groves and ridges unique to each individual.
Do you know what the ridges and groves are called?
FINGERPRINTS

8. Dermis Deeper areas contain a network of collagen and elastic fibers
These elastic fibers decrease with age contributing to wrinkles
Dermis also contains
Nerve endings
Sweat and sebaceous glands
Blood vessels
Muscle fibers
Hair follicles

9. Appendages of the skin HAIR
Born with hair all over our bodies. Newborn hair is called lanugo
Hair follicle- an epidermal tube- like structure required for hair growth
Shaft- visible part of the hair
Root= lies hidden in the follicle
Hair papilla- where hair growth begins
Hair bulb- at the base of the follicle (hair papilla is located here)
Arrector pili- specialized muscle that produces goose pimples

10. Receptors
Specialized nerve endings – makes it possible for skin to act as a sense organ
Meissner’s corpuscle- detects light tough
Pacinian corpuscle- capable of detecting pressure

11. SKIN GLANDS TWO TYPES Sweat (sudoriferous) Sebaceous
Sweat or Sudoriferous Glands
Eccrine sweat glands-most numerous, important and wide spread.
Produce perspiration, which flows out through pores on the surface of the skin
Assist with body temperature regulation

12. Sweat or sudoriferous glands
Apocrine sweat glands
Found primarily in the axilla and genitalia
Secrete a thicker milky secretion
Breakdown of secretion by skin bacteria produces odor
WHEN DO APOCRINE SWEAT GLANDS ENLARGE AND START FUNCTION?
PUBERTY

13. Sebaceous glands Secrete oil or sebum for hair and skin
Level of secretion increases during adolescence
Amount of secretion regulated by sex hormones
Sebum in sebaceous gland ducts may darken to form a blackhead
Acne vulgaris- inflammation of sebaceous gland ducts

15. Structure of the skin