1. Integumentary System
Chapter 5

2. • Skin & Accessory organs:
Hair & hair follicles
sebaceous (oil) glands
sudoriferous (sweat) glands
nails

3. Functions of the Integumentary
System
1. Protection: from exterior elements
2. Sensation: feeling
3. Excretion of wastes: sweat
4. Synthesis of Vitamin D in sunlight
5. Temperature regulation: release/retain heat
6. Coloration: pigment of skin
7. Water proof: water does not enter inside
8. Growth and repair: regenerate

4.  Skin structure 3 main layers
1. Epidermis:outer, thinner layer connected to the
basement membrane
2. Dermis:inner, thicker layer
3. Hypodermis / subcutaneous layer (Sub Q):
Under the dermis (adipose tissue)

5. List & Describe the 4 Cells in
Epidermis
 Found on pg. 152 in textbook
 5 Minutes to locate & write…GO!

6. Cells of the Epidermis
 Keratinocytes – produce the strong protein
keratin.
 Melanocytes – produce the brown pigment
melanin
 Langerhans’ cells –macrophages that help
activate the immune system response
 Merkel cells – function as touch receptors
in association with sensory nerve endings

7. General Epidermis Info
 Basement membrane= located right
underneath the stratum basale and
connects epidermis to the dermis

8. Layers of the Epidermis
Figure 5.2b

9. Epidermis
 outermost layer
 Made of keratinized stratified squamous
tissue, so it:
 Lacks blood vessels
 Is mostly dead
 There are 5 distinct layers
 MITOSIS does occur in bottom layers

10. 5 layers of the Epidermis
 Pg 154 in textbook

11. Stratum basale
 innermost layer
 directly above the
basement membrane
 location
• Merkel Cells
• Melanocytes
 Simple cuboidal
 Cells undergo mitosis
here

12. Stratum spinosum
 composed of many
layers of rounded
cells with large nuclei
 Langerhans’ cells are
abundant in this layer

13. Stratum granulosum
 composed of 3-5 layers of
flattened granular cells
 Cells start keratinization
process here the
process of cells formed in
the stratum basale
moving up, flattening,
dying, and becoming hard
and waterproof

14. Stratum lucidum
 translucent layer
 Not shown in
book…why?
 Because only
located in thick skin
of soles and palms

15. Stratum corneum
 Top layer
 composed of dead
epithelial cells being
flaked off (keratinized)
 Functions include:
 Waterproofing
 Protection from
abrasion and
penetration

17. Dermis
 inner layer
 Much thicker than the epidermis
 Dermis aka. “True Skin”
 Contains nerve endings, muscle fibers, hair
follicles, sudoriferous glands, sebaceous glands,
and blood vessels.
 Does not continually shed and regenerate itself

18. Dermis: 2 Layers
1. Papillary Layer
 Arranged in ridges
 The fingertips and toe tips
 Ridges allow us to grip things

19. Dermis: 2 Layers…cont’d
2. Reticular Layer
 Collagenous fibers: make our skin tough
 Elastic fibers: make our skin stretchable.
 Reticular fibers: gives skin its strength & resilience
 Location of smooth muscle called arrector pili
Stands hair on end when “goose bumps”

20. Subcutaneous layer or hypodermis
 adipose tissue and blood vessels
 beneath the dermis
 Function – insulation

21. Cutaneous Sensation
1. Light touch
detection:
Meissner’s Corpuscles
 located in dermal
papillae of dermis

22. Cutaneous Sensation
2. Pressure detection =
Pacinian Corpuscles
 located deep in dermis
and subcutaneous
regions

23. Hair
 Shaft: visible part of the hair
 Medulla: inner core of
the hair
 Cuticle: layer covering
medulla
 Cortex: Superficial
portion of hair
 Root: in dermis

24. No need to know for test…
 Just an Interesting FACT:
 Straight hair has a rounded follicle
 Wavy hair has a flattened follicle
 Kinky or curly hair has a kidney shaped follicle

25. Are you ready
to be grossed
out?...................…

26. Eye Lash Mites

27. Skin Color
 3 pigments contribute to skin color
 Melanin – yellow to reddish-brown to black
pigment, responsible for skin colors, related to
genetics
• Freckles and pigmented moles – result from local
accumulations of melanin
 Carotene – yellow to orange pigment
 Hemoglobin – reddish pigment responsible
for the pinkish hue of the skin

28. Pigment
More about Melanin:
 Is produced by melanocytes in stratum
basale layer
 People of different races have essentially
the same # of melanocytes, but the
amount of melanin produced varies

29.  The quantity of Melanin produced
depends on 3 factors:
1. Heredity: MOST IMPORTANT
• enzyme tyrosinase is absent at birth, then
melanocytes are unable to produce melanin and a
condition known as albinism is formed
2. Sunlight Exposure
• Causes melanocytes to increase melanin
production and darkening skin color
3. Hormones: ACTH (Adrenocorticotropic
Hormone ) and MSH (melanin stimulating
hormone)
• Hypersecretion of either hormone may darken the
skin

30. Albinism

31. Carotene

32. Hemoglobin

33. Nails cont’d…
 Tightly packed hard, keratinized epidermal
cells
 Functions = manipulation and protection

34. Ripley’s Believe It or Not Lady

35. Sudoriferous Glands
Two types
1. Eccrine  more common, mainly in forehead,
palms, & soles. These function right at birth. -
no odor in secretion
Secretion = water plus salts and wastes (urea
and uric acid)
2. Apocrine Mainly in armpits, groin, & breasts.
Don’t function until puberty. These cause the
“cold-sweat” during stress. -odor in secretion

36. Sebaceous Glands
 -Connected to every hair follicle
 -Secrete sebum (oil) into hair follicle
Function – sebum keeps skin and hair soft
Disorders
 acne = overproduction of sebum – ducts
clog and inflame

37. Ceruminous Glands
 Associated with ears
 Produces cerumen (earwax)