1. The Integumentary System

2. General Info…….. Skin has 2 layers Epidermis - outer layer
Dermis – inner layer
Sweat glands excrete sweat through pores.
Sweat is made up of urea, salts, and water.
Body’s first line of defense!
Largest organ of the body.

3. The “Birthday Suit” Combination of 4 main tissues:
Epithelial – outer layer
Connective – underlies dermis
Smooth Muscle – goose bumps
Nervous – sensory receptors

4. Functions of the Skin Protection Temperature regulation Sensations
Storage of chemical compounds
Excretion of wastes
Synthesis of compounds
Determines characteristics

5. The Skin FG04_02.JPG Title: Components of the Integumentary System
Notes: Relationships among the major components of the integumentary system (with the exception of nails, shown in Figure 4-15).
Keywords: integumentary system, cutaneous, epidermis, dermis, papillary layer, reticular layer, hair follicles, exocrine glands, nails

6. Epidermis Outer layer of dead skin cells called cuticle .
Layer you see everyday.
“Ashiness” is caused by this layer of dead skin cells being very rough and raggedy.
DUST you see around is made up of dead skin cells!
Under the cuticle is another layer of living epithelial cells that make up the rest of the epidermis.

7. Epidermis and Dermis Epidermis is avascular (no blood vessels)
Dermis is highly vascular (has blood vessels)
Epidermis receives nourishment from dermis
Cells far away from nourishment die

8. Epidermis FG04_03.JPG Title: The Structure of the Epidermis
Notes: A light micrograph through a portion of the epidermis, shows the major stratified layers of epidermal cells.
Keywords: epidermis, structure, layers, stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, stratum germinativum, dermis

9. Dermis Thick layer under the epidermis Contains blood vessels
Oil glands
Sweat glands
Hair follicles
Fat tissue
Nerves
Connective tissue

10. Deeper Layer of the Dermis
Dense connective tissue
Contains
Blood vessels
Glands
Deep pressure receptors
Attached to underlying organs by the subcutaneous layer
Loose connective tissue
Packed with adipose cells
Stabilizes position of skin

11. Human Anatomy, 3rd edition
Fingerprints
Human Anatomy, 3rd edition
Prentice Hall, © 2001

12. What Else Comes from the Epidermis?
Hair
Glands
Nails

13. Functions of Hair
Protection
Thermoregulation
Sensory
Minor role in humans

14. Hair Structure Shaft Superficial portion Root Below the surface
Cuticle
Outermost layer of hair
Hair develops in follicles
Downward continuation of epidermis

15. Hair Structure FG04_10A.JPG Title: Hair Follicles
Notes: Hairs originate in complex organs termed follicles. (a) A longitudinal section and a cross section through a hair follicle. (b) and (c) A section along the longitudinal axis of a hair follicle.
Keywords: hair follicle, longitudinal section, cross section, sebaceous gland, arrectory pili muscle, cortex, cuticle, internal root sheath, connective tissue layer, glassy membrane, external root shaft

16. Growth of Hair At the base of the follicle, hair papilla Bulb
Contains blood vessels and nerves
Nourishes hair
Bulb
Contains matrix – epithelial cells responsible for growth
Contains melanocytes

17. Smooth muscle attaches to follicle Raises hairs
Arrector Pili
Smooth muscle attaches to follicle
Raises hairs
Response to fright or cold
Function?

18. Glands
Sebaceous glands
Connected to hair follicles
Secrete a waxy, oily substance (sebum)
Blackheads
Secretion increases at puberty

19. Sebaceous Glands FG04_13A.JPG Title: Sebaceous Glands and Follicles
Notes: The structure of sebaceous glands and sebaceous follicles in the skin.
Keywords: sebaceous glands, sebaceous follicles, structure, sebum, germinative cells

20. Glands Sweat glands Found just about everywhere Produce “perspiration”
Water, salt, met. Wastes
Function – cooling of the body
Scent Glands
Specific type of sweat gland
Found near hair follicles
Axillary & genital regions
Develop at puberty

21. The Skin with Sweat Glands
FG04_02.JPG
Title: Components of the Integumentary System
Notes: Relationships among the major components of the integumentary system (with the exception of nails, shown in Figure 4-15).
Keywords: integumentary system, cutaneous, epidermis, dermis, papillary layer, reticular layer, hair follicles, exocrine glands, nails

22. Nail Structure
Nail body
Free edge
Nail root
Matrix
Lunula (moon)

23. Nail Structure FG04_15.JPG Title: Structure of a Nail
Notes: These drawings illustrate the prominent features of a typical fingernail as view from the surface and in section.
Keywords: fingernail, hyponychium, nail bed, lateral nail groove, lunula, eponychium, phalanx, dermis, epidermis

24. The skin also helps control body temperature- Homeostasis!
When you sweat, heat leaves the body through your pores.
When the sweat hits the outer surface of the skin, it is cooled by the air.
This lowers your body temperature.

25. The Amazing Body- Skin

26. Use the following vocabulary to label the diagram: hair shaft, oil (sebaceous)gland, fat cells, erector pili muscle, blood vessels, nerve endings, epidermis, dermis, cuticle, epithelial cells, hair follicle, sweat gland, connective tissue