1. Accessory Structures

2. Accessory structures are tissues that are located in the dermis and epidermis that are not considered skin These structures include hair, nails and glands These structures play a vital role to in the function and purpose of the skin

3. Accessory Structures Accessory structures derive from the epidermis during fetal development This means that the same cells that create the epidermis also create all of the accessory structures Since they come from the epidermis during development, we often refer to them as epidermal derivatives

4. Accessory Structures The accessory structures are located in the dermis However accessory structures should have access to the outside environment through the epidermis The only times this does not happen is if a gland is blocked or a hair is ingrown https://www.youtube.com/watch?v=zWh_eA-9S7E https://www.youtube.com/watch?v=Aj7aRGQ0DyI

5. Hair Hair is an accessory structure that projects from the dermis to the outer environment It covers most parts of the body This excludes the palms, bottom and sides of feet, lips and parts of the genitals Only around 25% of the bodies hair is located on the head The rest are located around the body

6. Hair Hair serves three main functions Insulate the skin Protect the skin from damage Sense changes to the skin from the environment These different functions happen all over the body in many different ways The purpose they serve makes sure we survive

7. Hair Structure Hairs are non living structures that are pushed upward from the dermis Hairs originate from a point called the hair follicle This hair follicle is surrounded by connective tissue (root hair plexus) and smooth muscle (arrector pili)

8. Hair Structure Hairs tissues are located below the surface and above the surface The part that is below the surface and anchors the hair into the skin is called the hair root The part that is above the surface and exposed to the environment is called the hair shaft

9. Hair Fun Facts Hairs are present for around two to five years During this time they grow around 8mm (1/3 of an inch) a month When new hairs grow, they push out the old hairs Humans lose around 100 hairs from their head a day

10. Hair Fun Facts There are two main different types of hair Vellus hairs are located all over your body and are less thick and lightly colored Terminal hairs are heavy and darkly pigmented Types of hairs that are produced can change with age and the levels of hormones produced

11. Hair Fun Facts Hair color is derived from melanin Melaninicytes near the hair follicle produce melanin that give the hair is color The melanin type produced is the color of hair As hair grows older, less melanin is produced and air finds its way into hair This causes hair to have a white or grey appearance

12. Hair Fun Facts Hair coloring can produce a false color on the shafts of hair However these hair dyes need to penetrate the hair so they damage the outer cuticle of the hair This often leaves hair damaged and thin Conditioners and specialized shampoos can partially restore the cuticle and leave hair hydrated

13. Video Not everyone’s hair grows the same… http://videos.howstuffworks.co m/discovery/30742-one-step- beyond-hypertrichosis- video.htm http://videos.howstuffworks.co m/discovery/30742-one-step- beyond-hypertrichosis- video.htm

14. Video Even more differences… www.youtube.com/watch?v=OU 93tt3w_eQ www.youtube.com/watch?v=OU 93tt3w_eQ http://www.dailymail.co.uk/heal th/article-2647395/Alopecia-big- life-doesnt-define-Teenager-15- lost-hair-disease-fronts-new- campaign.html http://www.dailymail.co.uk/heal th/article-2647395/Alopecia-big- life-doesnt-define-Teenager-15- lost-hair-disease-fronts-new- campaign.html

15. Nails Nails protect the exposed dorsal surfaces of the fingers and toes They also provide physical protection to the fingers when gripping an object They give it a backing so the cells do not distort to the point where they are not able to hold the object

16. Nails The nail body is the visible portion of the nail that covers part of your finger This part of your finger that is covered by the nail body is the nail bed The nail hyponychium occurs at the far distal edge of the nail and provides a seal to protect the nail bed This part of your body requires protection due to the amount of physical damage that It can and will receive over its lifetime

17. Nails The nail grows from an area called the nail root The nail root is an epidermal fold that is not visible from the surface The deepest portion of the root lies very close to the bones in the fingers and toes The cuticle is a section of nail root that comes over the exposed surface of the nail

18. Nails The condition of nails often tells a story of the health of an individual Persons that have yellowing nails might have various disorders that can inhibit or damage the nails during development Other signs of problems are pitted nails or nails that are concave as opposed to convex

19. Sebaceous Glands Found within the skin there are two major exocrine glands These glands are used to lubricate/hydrate the skin and maintain levels of temperature Sebaceous glands are glands that discharge an oily secretion Sweat glands are designed to release a

20. Sebaceous Glands Sebaceous glands are linked to a hair follicle This means that they share their opening to the skin with a follicle of hair They produce a large quantity of lipids that will dump onto the hair as it grows and the surrounding skin

21. Sebaceous Glands The mixture of lipids that are produced is called sebum Sebum is made of cholesterols, triglycerides, proteins and electrolytes It serves many purposes It inhibits microbial growth It lubricates and protects the hair shaft It lubricates and protects the skin

22. Sebaceous Glands Sebaceous follicles are large sebaceous glands that are not associated with hair follicles These are located mostly on the face, back, chest, nipples and genitals These are most active during fetal development and during puberty

23. Sweat Glands There are two main types of sweat glands Apocrine sweat glands are secrete their products onto hair follicles Merocrine sweat glands discharge their products onto skin

24. Sweat Glands Apocrine sweat glands are coiled under the skin They are located in the arm pits, around the nipples and in the genitals They produce a sticky and oily secretion They start producing at puberty and will continue for the rest of your life

25. Sweat Glands The sweat produced by these glands is rich in nutrients and can be a good source for bacteria This tends to create a large amount of odor Several different methods can be used to neutralize these odors, however many can have side effects

26. Sweat Glands Merocrine sweat glands will produce a very watery sweat that is dumped directly on the surface of the skin These sweat glands are designed to help cool the surface of the skin This robs heat from the body and will cool the body quickly

27. Demo

28. Sweat Glands The sweat produced by these glands is around 99% water Small amounts of other chemicals are in the sweat NaCl is the most major It functions to cool the skin It also helps dissolve/dilute other harmful chemicals that can be on the skin It also helps excrete water or electrolytes to maintain homeostasis

29. Video https://www.youtube.com/watc h?v=IAAt_MfIJ-Y https://www.youtube.com/watc h?v=IAAt_MfIJ-Y