The document summarizes the key components and functions of the integumentary system. It discusses the epidermis and dermis layers of the skin, how they provide protection and regulate temperature and moisture. It describes hair follicles, glands, nails and pigmentation. The document also addresses how skin responds to injury through regeneration and how it ages over time, with thinning and slower repair.

1. The Integumentary System

2. Learning Objectives
• List the components of the integumentary system,
including their physical relationships.
• Specify the functions of the integumentary system.
• Describe the main features and functions of the
epidermis and dermis.
• Discuss individual and racial differences in skin.
• Discuss the effects of UV light on the epidermis.
• Explain the structure and function of the various
accessory organs of the skin.
• Explain how the skin responds to injury and aging.

3. • Cutaneous membrane
• Epidermis
• Dermis
• Accessory structures
• Subcutaneous layer
The integumentary system consists of

4. • Protection
• Excretion
• Temperature maintenance
• Nutrient storage
• Vitamin D3 synthesis
• Sensory detection
Integumentary system functions:

5. Figure 5.1 The Components of the
Integumentary System
Figure 5.1

6. SECTION 5-2
The Epidermis

7. • The epidermis is composed of layers of
keratinocytes
• Thin skin = four layers (strata)
• Thick skin = five layers
Figure 5.2 Thin Skin and Thick Skin
Figure 5.2

8. • Provides mechanical protection
• Prevents fluid loss
• Keeps microorganisms from invading the body
The epidermis

9. • Stratum germinativum
• Stratum spinosum
• Stratum granulosum
• Stratum lucidum
• Stratum corneum
Layers of the epidermis:

10. Figure 5.3
Figure 5.3 The Epidermal Ridges of Thick Skin

11. • Cells accumulate keratin and eventually are shed
• Epidermal ridges are interlocked with dermal
papillae
• Fingerprints
• Improve gripping ability
• Langerhans cells (immunity) in s. spinosum
• Merkel cells (sensitivity) in s. germinativum
Epidermal characteristics:

12. Figure 5.4 The Structure of the Epidermis
Figure 5.4

13. • Blood supply
• Carotene and melanin
• Melanocytes produce melanin and protect
from UV radiation
• Epidermal pigmentation
• Interrupted blood supply leads to cyanosis
Skin color depends on

14. Figure 5.5 Melanocytes
Figure 5.5a, b

15. • Synthesize vitamin D3 (cholecalciferol) when
exposed to UV
• Respond to epidermal growth factor
• Growth
• Division
• Repair
• Secretion
Epidermal cells

16. SECTION 5-3
The Dermis

17. • Papillary layer
• Contains blood vessels, lymphatics, sensory
nerves of epidermis
• Reticular layer
• Contains network of collagen and elastic fibers
to resist tension
Dermal Organization

18. Figure 5.8 Dermal Circulation
Figure 5.8

19. • Caused by excessive stretching of the dermis
• Patterns of collagen and elastic fibers form lines
of cleavage
Stretch marks

20. Figure 5.7 Lines of Cleavage of the Skin
Figure 5.7

21. • Cutaneous plexus arteries found in subcutaneous
layer/ papillary dermis
• Cutaneous sensory receptors (light touch,
pressure)
Dermal Circulation and innervation

22. • Stabilizes skins position against underlying
organs and tissues
Hypodermis

23. SECTION 5-5
Accessory Structures

24. • Originate in hair follicle
• Composed of root and shaft
• Root base (hair papilla) surrounded by hair bulb
and root hair plexus
• Hairs have soft medulla and hard cortex
• Cuticle = superficial dead protective layer
Hairs

25. Figure 5.9 the Anatomy of a Single Hair
Figure 5.9

26. • Vellus hairs (peach fuzz)
• Terminal hairs ( heavy)
• Club hair (cessation of growth)
• Shed and grow according to hair growth cycle
Arrector pili muscle attaches to hair
Hair types

27. Figure 5.10 Hair Follicles
Figure 5.10a-c

28. • Sebaceous
• Suderiferous
• Mammary
• Ceruminous
Glands in the skin

29. • Discharge waxy sebum onto hair shaft when
associated with hairs
• Sebaceous follicles discharge onto epidermal
surface
Sebaceous glands

30. Figure 5.11 Sebaceous Glands and Follicles
Figure 5.11

31. • Apocrine sweat glands
• Produce odorous secretion
• Merocrine (eccrine) sweat gland
• Sensible perspiration
Suderiferous glands

32. Figure 5.12 Sweat Glands
Figure 5.12a, b

33. • Mammary glands
• Structurally similar to apocrine sweat glands
• Ceruminous glands
• In ear, produce waxy cerumen
Other glands

34. • Nail body covers the nail bed
• Nail production occurs at the nail root
• Eponychium (cuticle) overlies root
• Free edge of nail extends over hyponychium
Nails

35. Figure 5.13 The Structure of a Nail
Figure 5.13

36. SECTION 5-7
Local Control of Integumentary Function

37. • Regenerates easily
• Regeneration process includes formation of
• Scab
• Granulation tissue
• Scar tissue
Injury and repair

38. Figure 5.14 Integumentary Repair
Figure 5.14, step 1-2

39. Figure 5.14 Integumentary Repair
Figure 5.14, step 3-4

40. SECTION 5-4
The Subcutaneous Layer

41. • The components of the integumentary system,
including their physical relationships.
• The functions of the integumentary system.
• The main features and functions of the epidermis
and dermis.
• Individual and racial differences in skin.
• The effects of UV light on the epidermis.
• The structure and function of the various
accessory organs of the skin.
• How the skin responds to aging.
You should now be familiar with:

42. SECTION 5-7
Aging and the Integumentary System

43. • Integument thins
• Blood flow decreases
• Cellular activity decreases
• Repairs occur more slowly
With age