1. INTEGUMENTARY SYSTEM Skin, Hair, Nails, Skin Glands

2. Skin Fact
In 1 square inch of skin there are 4 yards of nerve fibers, 1300 nerve cells, 100 sweat glands, 3 million cells, and 3 yards of blood vessels.

3. Brainstorm Write and discuss with someone near you something you know about the integumentary system. 1 2
Integumentary System
SKIN 3 4

5. Functions of the SKIN
1. The body’s 1st line of defense against germs and pathogens
2. Insulates body
3. Stored source of energy
4. Shock-absorbing pad
5. Waterproof layer

6. SKIN Cutaneous membrane (sheet-like organ) Made of two layers
1. Epidermis: outer layer, thin sheet of stratified squamous epithelium
2. Dermis: thicker, made largely of connective tissue
Both layers are supported by a thick layer of loose connective tissue and fat: subcutaneous tissue

7. EPIDERMIS: layered epithelial cells
Made of layers called STRATA
1. Stratum germinativum:
-innermost layer, undergoes mitosis enabling skin to repair itself
-new cells move upward, near surface is replaced with keratin (tough, waterproof)

8. EPIDERMIS: layered epithelial cells
2. Stratum corneum:
- outer layer of epidermis
- keratin filled cells are pushed to surface, are dislodged and flake off

9. Epidermis
The epidermis contains four (thin skin) to five major layers (thick skin):
Stratum basale (deepest layer)
Stratum spinosum, 8-10 layers of keratinocytes
Stratum granulosum – thin layer where keratinocytes become filled with keratin, flatten, and lose their nuclei.
Stratum lucidum is present only in thick skin (fingertips, palms, and soles), reduces friction, clear under microscope. Dead cells.
Stratum corneum (most superficial)

10. Layers of the Epidermis

11. Cells of the Epidermis
Keratinocytes (90% of the cells) produce keratin which is a tough fibrous protein that provides protection
Melanocytes: which produce the pigment melanin that protects against damage by ultraviolet radiation

12. Cells of the Epidermis
Langerhans cells: involved in immune responses, arise from red bone marrow
Merkel cells: which function in the sensation of touch along with the adjacent tactile discs

13. Types of Cells in the Epidermis

14. Dermal-epidermal Junctions
Area of contact between the dermis and epidermis
Blisters will form here if the junction is damaged

15. DERMIS Deeper of the two primary layers
Contains nerves and nerve endings, muscle fibers, hair follicles, sweat and sebaceous glands, and blood vessels

16. DERMIS Dermal papillae
- peg-like projections of upper region of dermis, part of dermal-epidermal junction
- form grooves that make fingerprints

17. Callus & Corn Examples
Calluses are generally on the soles of the feet

18. Corns
Corns are between the toes or on the outside of the toes.

19. Skin Color Melanocytes Produced by a skin pigment called MELANIN
Melanin also produces freckles and moles

20. Albino – no melanin

21. Part II: Appendages and Functions of the Skin
INTEGUMENTARY SYSTEM
Part II: Appendages and Functions of the Skin

22. SKIN FACTS
Fingernails grow nearly 4 times faster than toenails.

23. Which layer of the dermis is responsible for fingerprints?
The papillary layer is the layer of the dermis responsible for fingerprints.
Which layer of the epidermis is the stratum where dandruff, calluses, and corns occur?
The layer of the epidermis where dandruff, calluses and corns occur is the stratum corneum.
What is the pigment called that gives our skin its color?
What is the cell that produces this pigment?
The pigment that gives our skin its color is melanin and the cell that produces this pigment is a melanocyte.

24. HAIR Follicles are present at birth
Lanugo: fine, soft hair of newborn; falls out shortly after birth
Hair follicles: cells of epidermal layer grow down into dermis forming a small tube

25. HAIR
Hair papilla: small cap-shaped cluster of cells where hair growth begins (nourished by dermal blood vessels)
Hair root: hidden in follicle
Hair shaft: visible part, dead, keratinized epithelial cells

26. HAIR Hair color – mostly due to melanin
New hair will replace any lost as long as the hair follicle remain alive

27. HAIR
Arrector pili muscle: bundles of smooth muscle that cause hairs to “stand up”, usually only contract when frightened or cold (goose bumps)

28. HAIR

29. RECEPTORS Make it possible for skin to act as a sense organ
1. Meissner’s corpuscle: located close to surface, detecting sensations of light touch

30. RECEPTORS
2. Pacinian corpuscle: located deep in dermis, detects pressure of skin’s surface

31. NAILS Nail body: visible part
Root: hidden by a fold of skin, cell division occurs here
Cuticle: fold of skin over nail root

32. NAILS
Lanula: crest-shaped white area near root, extent of growing region
Nail bed: layer of epithelial tissue under the nail body, rich in blood vessels, appears pink

33. SKIN GLANDS Sweat (sudoriferous) glands:
1. Eccrine sweat glands- most numerous, small and distributed over most of body’s surface, produces perspiration which eliminates wastes(ammonia, uric acid), helps maintain body temperature
Functions to cool the body, also released during stress

34. SKIN GLANDS
2. Apocrine sweat glands—primarily in skin of armpit and genitalia, secrete a milky secretion, odor caused by contamination and decomposition of secretion by skin bacteria, enlarge and begin to function at puberty

35. SKIN GLANDS
Sebaceous glands: secrete oil, ducts open into hair follicles, sebum is the secretion that lubricates hair and skin (increases during adolescence)
A build up of oil and dirt causes acne

36. The Effects of Aging on Skin
blood flow to the skin is reduced
skin becomes thinner & more transparent
less elastin & fat causes wrinkles
less collagen – more easily damaged
age spots, discoloration, gray hairs

37. Skin Cancer BASAL CELL CARCINOMA most frequent type of skin cancer
begins in stratum basale and goes into dermis
treatment: surgery or radiation
does not metastasize

38. SQUAMOUS CELL CARCINOMA
cells above statum basale
SQUAMOUS CELL CARCINOMA
can metastasize & cause death

39. MALIGNANT MELANOMA from melanocytes in a mole
can metastasize & cause death

41. Acne infection involving hair follicle & sebaceous gland
also can have a significant hormonal cause

42. Skin Diseases Athlete’s Foot Acne Vulgaris Boils and Carbuncles
Impetigo
Basal Cell Carcinoma
Squamous Cell Carcinoma
Alopecia
Albinism
Warts (verrucae)
Keloids
Scabies
Acne Vulgaris
Psoriasis
Herpes Simplex I (cold sores)
Eczema
Herpes Zoster (Shingles)
Malignant Melanoma
Ringworm
Genital Herpes

43. Burns The Integumentary System

44. Burns may be caused by … Fire Hot surfaces UV rays Electric currents
Chemicals

45. Treatment & Recovery
Depends on the total amount of the body burned & the severity of the burn

46. “Rule of Nines”
– used for adults to estimate the percentage of the body burned

47. “Rule of Nines”
must be adjusted slightly for children because their proportions are different from adults

48. Classifying Burns
Degree of burn is decided according to the number of skin layers involved

49. First Degree Burn – involves only the upper epidermis
causes reddening of the skin, minor discomfort
Ex.) mild sunburn

50. Second Degree Burn – involves deep epidermal layers and damages upper dermal layers
damages sweat glands, hair follicles, sebaceous glands
causes blistering, severs pain, swelling, fluid loss, scarring

51. Third Degree Burns – complete destruction of the epidermis and dermis, damages the subcutaneous tissue & sometimes muscle and bone
lesions are insensitive to pain at first
causes serious scarring, extremely susceptible to infection