1. Lecture 5
Integumentary System

2. Integumentary System Consists of: Functions Skin (Epidermis & Dermis)
Accessory structures
Hair
Nails
Glands
Functions
Protection
Sensation
Temperature regulation
Vitamin D production
Excretion
Fig. 5.1

3. Epidermis and Dermis
Fig. 5.2

4. Epidermal Cells Cell types
Keratinocytes: Produce keratin for strength
Melanocytes: Contribute to skin color (pigment melanin)
Langerhans’ cells: Part of the immune system
Merkel’s cells: Detect light touch and pressure
Fig. 5.2
Keratinization: Cells die and produce outer layer that resists abrasion and forms permeability layer

5. Epidermal Strata Stratum Basale Stratum Spinosum Stratum Granulosum
Deepest portion of epidermis and single layer
High mitotic activity
Stratum Spinosum
Limited cell division
Stratum Granulosum
In superficial layers nucleus and other organelles degenerate and cell dies
Fig. 5.2

6. Epidermal Strata Stratum Lucidum Stratum Corneum Thin, clear zone
Most superficial and consists of cornified cells
Squamous in shape, filled with keratin
Fig. 5.2

7. Dermis Structural strength Two layers
Deeper layer - dense connective tissue; stretch marks (striae)
Superficial layer underneath epidermis - loose connective tissue
Fig. 5.6

8. Review Question
The layer of keratinocyte cells of the epidermis with the highest rate of cell division is the
Stratum spinosum
Stratum basale
Stratum corneum
Stratum granulosum
Stratum lucidum

9. Hypodermis Skin rests on this, but not a part Also called
Subcutaneous tissue
Superficial fascia
Consists of loose connective tissue
Types of cells
Fibroblasts
Adipose (fat) cells
Macrophages
Subcutaneous fat
Fig. 5.6

10. Accessory Skin Structures
Hair
Found everywhere on human body except palms, soles, lips, nipples, parts of external genitalia, and distal segments of fingers and toes
Nails
Glands
Sebaceous or oil glands
Sudoriferous or sweat glands

11. Hair Structure Composed of shaft and root Arrector pili
Shaft protrudes above skin surface
Root located below surface and base forms the hair bulb
Hair follicle consists of layer of dermis and epidermis
Arrector pili
Smooth muscle
Raises hair
Fig. 5.9

12. Nails Anatomy Growth Nail root proximally
Nail body distally: Eponychium or cuticle
Growth
Grow continuously unlike hair
Fig. 5.8

13. Oil and Sweat Glands Sebaceous glands Sudoriferous glands (sweat)
Produce sebum
Oils hair and skin surface
Sudoriferous glands (sweat)
Most commonly found in palms, soles and forehead
Also found in axillae (arm pit), genitalia, around anus
Ceruminous glands (cerumen or ear wax)
Mammary glands
Fig. 5.10

14. Points to Remember Two components to integumentary system
Skin (epidermis & dermis)
Accessory structures (hair, nails and glands)
Keratinization (accumulation of keratin) produces upper layer of cells of epidermis, hair and nails
Two types of glands in skin
Sebaceous (oily)
Sudiferous (watery)

15. Questions?