1. May 16, 2017
Journal: What makes up the Integumentary system?

2. Integumentary System

3. Functions: Protection Keeps the body from drying out
Stores fatty tissues to be used as an energy source
Produces vitamin D with the help of sunshine
Sensory input for your brain
Regulates body temperature

4. Skin Made up of 3 tissue layers: Epidermis Dermis
Subcutaneous fascia a.k.a. hypodermis

5. Epidermis Outermost layer of skin
Made up of 4-5 layers or stratified squamous epithelial tissue
Contains no blood vessels or nerve cells

6. Epidermis Layer Shedding
Surface cells are constantly shedding
Cells originate in the basal layer (stratum basale) and are pushed upward towards the surface
As they are pushed upwards the cells die and become filled with a protein called keratin
This process takes between 2 and 4 weeks

7. Layers of the Epidermis

8. Stratum corneum Dead cells on the outermost surface of the skin
Often shed
Typically flat, scaly, and keratinized (hardened) epithelial cells
Protect the layers underneath from drying out

9. Stratum lucidum
Layer of dead, keratinized epithelial cells only found in parts of the body with thick skin
Ex: Palms and heels
Functions in protection from UV rays

10. Stratum granulosum
Skin layer in the middle of the epidermis where living cells are filled with keratin and begin to die

11. Stratum spinosum
Living epithelial cells that do not receive nutrients from the dermis, but divide at a slow rate
Contain Langerhans cells that can produce an immune response when pathogens are present

12. Stratum basale
Living epithelial cells that receive nutrients from the dermis and undergo rapid mitosis to replace cells lost in the outer layers
Contains melanocytes which are responsible for producing pigment
Contains Merkel cells which are touch receptors

13. Melanocytes
Produce melanin, the substance that is responsible for your skin color
Variations in skin color are due to how much melanin is produced and how it is distributed around your body

14. Skin Color More sun = more melanin produced = tan
Freckles occur when melanin is found together in clumps
Yellowish skin tone is due to carotene
Pinkish skin tone is due to hemoglobin
Yellow jaundice occurs when liver disease occurs and the body can’t excrete waste

15. Dermis Layer right below the epidermis
Thick layer of irregular connective tissue

16. Two Layers within the Dermis:
Papillary Layer
Top layers of the dermis
Contains thin elastic and collagen fibers
Contains ridges that are responsible for fingerprints
Reticular Layer
Below the papillary layer
Contains tightly packed elastic and collagen fibers

17. Collagenous and elastic fibers
Helps your skin shift when you move your body otherwise it would tear
Allows skin to return to its normal shape when your body is at rest
Stretches out over time so skin loses it’s firmness and flexibility

18. Sweat Glands Apocrine sweat glands Eccrine sweat glands
Located near the hair follicles, groin, and armpits
Become active around puberty and act as a sexual attractant
Eccrine sweat glands
Located all over your skin
Regulate body temperature

19. Sebaceous Glands Oil glands that keep the skin from drying out
Destroys pathogens on the skin as well

20. Subcutaneous fascia Also known as hypodermis Innermost layer of skin
Composed of fatty tissues and elastic and fibrous connective tissue
Connects to the muscles of your body

21. Lipocytes
Fat cells produce the fat needed to protect the body and to act as insulation for regulating temperature