Journal #1: How is the integumentary system (skin) like an onion?

Vocabulary1. Integument2. Epidermis3. Dermis4. Subcutaneous layer5. Basal Cells6. Keratin7. Carotene8. Melanin

Objective: List the components of

the integumentary system and their relationship to each other

Specify the functions of the integumentary system

Ch.5 Integumentary System

Part 1: Layers

Pages 153-164

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

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

Layers (Strata) of the Epidermis

From Deepest to most Superficial Stratum Germinativum Stratum Spinosum Stratum Granulosum Stratum Lucidum Stratum Corneum

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)

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 cellsStimulate immune response to

microorganisms and cancer

Stratum Granulosum

“Grainy Layer” of 3-5 layers of keratinocytes

Lots of Keratin (tough protein) & Keratohyaline (promotes dehydration)

Thin flat cells with decreased permeability

Stratum Lucidum

In thick skin of palms and soles only Clear layer that covers the stratum

granulosum Flat, dense, and filled with keratin

Stratum corneum

Exposed surface of skin 15-30 layers of keratinized (dead) cells Takes 15-30 days for the cell to move

from stratum germinativum to the stratum corneum (2 weeks before it is shed)

Water resistant, not waterproof

Perspiration

Journal #2: Give the layers of the epidermis from the most superficial to the deepest.

Vocabulary9. UV Radiation10. Cyanosis11. Vitamin D12. Epidermal Growth

Factor13. Papillary Layer14. Reticular Layer15. Hypodermis

Objective: List the components of

the integumentary system and their relationship to each other

Specify the functions of the integumentary system

Skin Color Pigmentation

Carotene 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

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

The Dermis Components

Papillary 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

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

Subcutaneous Layer

HypodermisStabilizes skin in relation to muscles and

other organsAreolar and adipose (baby fat) tissueVenous circulation contains a great amount of

blood Subcutaneous injection effective