1. Turner College & Career High School
Integumentary System
An Introduction
Turner College & Career High School
2014

2. Integumentary System The integument is an organ:
The integument is an organ, and is an alternative name for skin.
The integumentary system includes the skin and the skin derivatives hair, nails, and glands.
The integument is the body’s largest organ and accounts for 15% of body weight.

3. Functions of the Integumentary System
Protects against
abrasion
chemical damage
drying out
UV radiation damage
Regulates body temperature

4. Functions of the Integumentary System

5. Functions of the Skin
Thermoregulation: Evaporation of sweat & regulation of blood flow to the dermis.
Cutaneous sensation - Sensations like touch, pressure, vibration, pain, warmth or coolness.
Vitamin D production: UV sunlight & precursor molecule in skin make vitamin D.
Protection: The sin acts as a physical barrier.
Absorption & secretion: The skin is involved in the absorption of water-soluble molecules and excretion of water and sweat.

6. Functions of the Skin
Wound healing: When a minor burn or abrasion occurs basal cells of the epidermis break away from the basement membrane and migrate across the wound. 
They migrate as a sheet, when the sides meet the growth stops and this is called ‘contact inhibition’.
In deep wound healing: A clot forms in the wound, blood flow increases and many cells move to the wound.
The clot becomes a scab; granulation tissue fills the wound and intense growth of epithelial cells beneath the scab.
The scab falls off and the skin returns to normal thickness.

7. Anatomy of the Skin
Epidermis
Dermis
Hypodermis

8. Layers of the Epidermis
Epidermis: The Epidermis is the thinner more superficial layer of the skin. The epidermis is made up of 4 cell types:
Keratinocytes: Produce keratin protein a fibrous protein that helps protect the epidermis
Melanocytes: produces the brown pigment melanin
Langerhan Cells: participate in immune response
Merkel cells: participates in the sense of touch.

9. Epidermis – Cell Types Keratinocytes
Produce keratin – waterproofing protein
Originate in deeper layers & get pushed to surface – becomes keratin filled & dies
Connected to each other by desmosomes & tight junctions
Cell production & keratinization are accelerated in areas of friction
Callus – thickened skin

10. Epidermis – Cell Types Melanocytes Produce melanin
Prevents DNA mutation from the UV radiation
UV increases melanin production
Same number in everyone, but different amount of pigment produced
Accumulation of melanin results in freckles and moles

11. Epidermis: Skin Color Determined by three factors:
Types of pigments present
Melanin
Brown, black, or yellow pigment
Carotene
Orange-yellow pigment from some vegetables
Vitamin A precursor; vitamin A forms retinal which is needed for sight
Accumulates in adipose and stratum corneum cells
Hemoglobin
Red, oxygen-carrying pigment in erythrocytes
More obviously detected in fair skin
Blood circulation
Stratum corneum thickness

12. Skin as a Diagnostic
Skin color is influenced by emotional & disease states:
Cyanosis: bluish color; lack of oxygen
Erythema: redness; heat, inflammation, fever
Albinism: genetically black, but white; no melanin produced from melanocytes
Pallor: paleness; lack of blood flow
Jaundice: yellowish color; liver damage; accumulation of bilirubin
Bronzing: bronze (tan); Addison’s disease
Hematomas: black & blue; blood under skin

13. Layers of the Epidermis
There are five distinct sub-layers of the Epidermis:
Stratum corneum: the outermost layer, made of layers of dead flat keratinocytes. Lamellar granules provide water repellent action and are continuously shed & replaced.
Stratum lucidum: Only found in the fingertips, palms of hands, & soles of feet. This layer is made up of 3-5 layers of flat dead keratinocytes.
Stratum granulosum: made up of 3-5 layers of keratinocytes, site of keratin formation, keratohyalin gives the granular appearance.
Stratum spinosum: appears covered in thornlike spikes, provide strength & flexibility to the skin.
Stratum basale: The deepest layer, made up of a single layer of cuboidal or columnar cells. Cells produced here are constantly divide & move up to apical surface.

14. Layers of the Epidermis

15. Epidermal Cells Keratinocytes Epidermal dendritic cells Merkel cells
Produce keratin, form layers of epidermis
Epidermal dendritic cells
Ward off infections
Merkel cells
Touch receptors

16. Dermis Dense, fibrous connective tissue Papillary layer
Forms fingerprints
Reticular layer

17. Layers of Skin: Dermis
Dermis: is the deeper, thicker layer composed of connective tissue, blood vessels, nerves, glands and hair follicles.
Contains three cell types:
Adipocytes,
Macrophages and
Fibroblasts.
Papillary region of the dermis:
Papillary region: The superficial layer of the dermis, made up of loose areolar connective tissue with elastic  fibers.
Dermal papillaee: Fingerlike structures invade the epidermis, contain capillaries or Meissner corpuscles which respond to touch.
Reticular region of the dermis: Made up of dense irregular connective & adipose tissue, contains sweat lands, sebaceous (oil) glands, & blood vessels.

18. Hypodermis Fibrous connective tissue Adipose tissue Padding Insulation
Energy storage

19. Appendages of the Skin Sudoriferous (sweat) glands Sebaceous glands
Eccrine
Apocrine
Merocrine
Sebaceous glands
Hair
Nails

20. Appendages of the Skin Glands
Participate in regulating body temperature.

21. Three main types of glands :
Sebaceous: Oil glands. Located in the dermis, and secrete sebum.
Sudoriferous: Sweat glands. Divided into two main types:
Eccrine: Most common, main function is regulation of body temperature by evaporation, and
Apocrine: Responsible for “cold sweat” associated with stress.
Ceruminous: Lie in subcutaneous tissue below the dermis, secrete cerumen (ear wax) into ear canal or sebaceous glands

22. Appendages of the Skin Hair
Functions include protection & sensing light touch.
Hair is composed of columns of dead, keratinized cells bound together by extracellular proteins.

23. The hair consists of:
Shaft: superficial portion that extends out of the skin; and
Root: portion that penetrates into the dermis.
Surrounding the root of the hair is the hair follicle.
At the base of the hair follicle is an onion-shaped structure called the Bulb Papilla of the hair and the matrix within the bulb produce new hair.

24. Hair & Hair Follicles Other Components: Medulla: central core
Cortex: area between medulla & cuticle
Cuticle: heavily keratinized; shingles
Arrector pili: smooth muscle, connects follicle to tissue
Matrix: growth zone
Hair bulb: contain melanocytes

26. Appendages of the Skin Nails
Participate in the grasp & handling of small things.
Nails are plates of tightly packed, hard, keratinized epidermal cells.

27. The nail consists of:
Nail root: the portion of the nail under the skin,
Nail body: the visible pink portion of the nail, the white crescent at the base of the nail is the lunula, the hyponychium secures the nail to the finger, the cuticle or eponychium is a narrow band around the proximal edge of the nail,
Free edge: the white end that may extend past the finger.

28. Nails Other Components: Nail folds: sides of nails, connected to skin
Cuticle: thick proximal nail fold
Lanula: crescent
Nail bed: extends beneath the nail
Nail matrix: thick part of nail bed; growth

30. Injuries & Disorders Injuries of the skin
Infections of the skin and membranes
Inflammatory conditions of the skin and membranes
Cancers of the skin

31. Homeostatic Imbalances
Over 1000 ailments of the skin!
Mostly allergies, fungus, burns, & cancer
Athlete’s foot—fungus
Boils/carbuncles—inflamed oil glands
Cold sores—herpes virus
Contact dermatitis—chemical contact
Impetigo—bacterial infection
Psoriasis—autoimmune disorder

32. Injuries of the Skin Decubitus ulcers Burns Bedsores
Caused by restricted blood supply
Burns
First-, second- or third-degree
Caused by heat, chemicals, electricity or UV radiation
Rule of nines
Suzanne Tucker/Shutterstock.com, JTeffects/Shutterstock.com, Naiyyer/Shutterstock.com

33. Burns Tissue damage/cell death caused by intense heat
Skin = thick as a paper towel
Almost all body systems suffer when skin is burned
2 life threatening problems: fluid loss & kidney shutdown/circulatory shock

34. Burns Rule of Nines: Infection is leading cause of death
Body divided into 11 areas, each covering 9% surface area
Helps determine volume of fluid lost
Infection is leading cause of death
Burns are sterile 24 hours after
Then pathogens invade

35. Infections of the Skin Viral infections Herpes varicella Herpes zoster
Herpes simplex virus type 1 or type 2
Human papillomavirus
Warts
Maksym Bondarchuk/Shutterstock.com

36. Infections of the Skin Fungal infections Bacterial infections
Athlete’s foot
Jock itch
Ringworm
Toenail fungus
Bacterial infections
Impetigo
Cellulitis

37. Inflammatory Conditions
Pleurisy
Makes smooth surface of pleura rough
Peritonitis
Infection of peritoneum
Psoriasis
Involves redness and irritation
Kenxro/Shutterstock.com

38. Cancers of the Skin Basal cell carcinoma Squamous cell carcinoma
Malignant melanoma
ABCD rule
Librakv/Shutterstock.com