1. Journal #1: How is the integumentary system (skin) like an onion?
Vocabulary
Integument
Epidermis
Dermis
Subcutaneous layer
Basal Cells
Keratin
Carotene
Melanin
Objective:
List the components of the integumentary system and their relationship to each other
Specify the functions of the integumentary system

2. Ch.5 Integumentary System
Part 1: Layers
Pages

3. Components of the Integument
Cutaneous Membrane
Epidermis
Dermis
Accessory Structures
Hair, Nails, & Glands
Subcutaneous layer
Hypodermis
Superficial Fascia/connective tissue
Function
Protection
Excretion
Maintenance of Homeostasis
Synthesis of Vitamin D
Storage of Lipids
Detection/ Receptors

4. The Epidermis Stratified Squamous Epithelium No Blood vessels
Many Keratinocytes
Cells that contain keratin
Thin Skin- most surfaces
Thick Skin- palms of hands/soles of feet

5. Layers (Strata) of the Epidermis
From Deepest to most Superficial
Stratum Germinativum
Stratum Spinosum
Stratum Granulosum
Stratum Lucidum
Stratum Corneum

6. Stratum Germinativum Hemidesmosomes attach cells to basal lamina
Form epidermal ridges and dermal papillae
Increase surface area
Genetically determined patterns are unique
Cells
Basal or Germinative Cells (stem cells)
Merkel Cells (touch receptors)
Melanocytes (skin pigmentation)

7. Stratum spinosum “Spiny Layer” of 8-10 rows of keratinocytes
Results from one of the daughter cells from stem cell division being pushed up from the stratum germinativum
Langerhans cells
Stimulate immune response to microorganisms and cancer

8. Stratum Granulosum “Grainy Layer” of 3-5 layers of keratinocytes
Lots of Keratin (tough protein) & Keratohyaline (promotes dehydration)
Thin flat cells with decreased permeability

9. Stratum Lucidum In thick skin of palms and soles only
Clear layer that covers the stratum granulosum
Flat, dense, and filled with keratin

10. Stratum corneum Exposed surface of skin
15-30 layers of keratinized (dead) cells
Takes days for the cell to move from stratum germinativum to the stratum corneum (2 weeks before it is shed)
Water resistant, not waterproof
Perspiration

11. Journal #2: Give the layers of the epidermis from the most superficial to the deepest.
Vocabulary
9. UV Radiation
10. Cyanosis
11. Vitamin D
12. Epidermal Growth Factor
13. Papillary Layer
14. Reticular Layer
15. Hypodermis
Objective:
List the components of the integumentary system and their relationship to each other
Specify the functions of the integumentary system

12. Skin Color Pigmentation Dermal Circulation Carotene Melanin
Orange yellow pigment in epidermal cells
Can convert to Vitamin A (needed in the growth of epidermal cells)
Melanin
Brown, yellow, or black pigment
Melanocytes produce it in the stratum germinativum and store in vesicles called melanosomes
Dark skinned people have larger melanosomes
Synthesis increases with UV exposure
Dermal Circulation
Red tones produced by hemoglobin in RBC’s
Cyanosis- blue tone to skin

13. Other Roles of the Epidermis
Steroid Production
UV Radiation in epidermal cells in the stratum spinosum and germinativum convert a steroid into cholecalciferol or Vitamin D
Helps in bone development and maintenance (Rickets-abnormal bone development due to lack of Vitamin D
Epidermal Growth Factor
Made by salivary glands and the glands of the duodenum
Functions
Promotes cell division in stratum germinativum and spinosum
Speeds up production of keratin in keratinocytes
Stimulates skin repair and development
Stimulates activity and secretion in epithelial glands

14. The Dermis Components Papillary Layer Reticular Layer
Areolar tissue with capillaries, lymph, and sensory neurons
Reticular Layer
Irregular connective tissue w/collagen fibers extending to subcutaneous layer
Blood vessels, lymph, and nerve fibers

15. Characteristics of the Dermis
Strength and Elasticity
Collagen & elastic fibers
Water content
Lines of Cleavage (pattern fibers make)
Cut parallel will heal with little scarring
Cut at a right angle will have greater scarring
Blood Supply
Arteries to subcutaneous and border reticular layer called cutaneous plexus
Innervation
Sensory reception
Light touch: tactile (Meisners’s) corpuscles
Deep pressure & vibration: lamellated (Pacinian) corpuscles

17. Subcutaneous Layer Hypodermis
Stabilizes skin in relation to muscles and other organs
Areolar and adipose (baby fat) tissue
Venous circulation contains a great amount of blood
Subcutaneous injection effective