1. Integumentary System: Appendages
Ms. Donis

2. RECAP VIDEO:

4. Appendages: Nails Hair Sweat Glands

5. Where do our nails and hair come from?

6. Where do our nails and hair come from?
Your nails are extensions of your epidermis, the nail contains a ton of dead cells
They are made of keratin made from keratinocytes. Keratin is what keeps your nails so stiff.
Your fingernails grow about 4x faster than your toenails

7. Free Edge: is the visible part of the nail, it is literally the edge of the nail
Body: the middle portion of the visible nail
Nail folds: skin surrounding your nail that are overlapping, they can be lateral or proximal.
Cuticle: the thick nail folds that accumulate proximally. It is a barrier of protection against infection
Lunula: is a an area of thickened nail matrix that appears white

8. Nail Matrix: is an extension of your epidermis
Nail Matrix: is an extension of your epidermis. Cells from the epidermis are growing horizontally, moving up from the strata basale to the strata corneum. The cells in the nail matrix are heavily keratinized, but dead.
Nail Root: is directly attached to your epidermis

9. Where do our hair and nails come from?
Nails are transparent, but adopt a pink color due to blood circulation found in the dermis.
The lunula is the only exception to this- it is a white crescent.

10. Where do our hair and nails come from?
Hair grows from the dermis (reticular layer, not the epidermis
Follicle
Arrector Pili Muscle
Grows at an average rate of 0.5 inches a month.

11. Where do our hair and nails come from?
Arrector Pili Muscle: keeps hair upright
Involuntary muscle that contracts, and causes hair to stand and skin to bunch up and create “goosebumps”
Muscle contraction occurs due to strong emotion or temperature change
Vestigial structure in humans

12. Polar bears have arrector pili muscles
Polar bears have arrector pili muscles. The hair on the polar bear will stantd up; the hair is a lot longer, makin this furry coat creates a warm insulating layer. We dont have that much use to it because we dont have hair, so its considered a vestigial muscle.

13. What’s in sweat?
Sweat Glands- are found in the reticular dermis, they have ducts that lead out to the external environment
There are three types of glands:
Holocrine/Sebaceous glands
Apocrine glands
Merocrine glands

14. Holocrine Glands/Sebaceous Glands
Found on the face, chest and back
Sebaceous glands empty into a hair follicle.
Holocrine glands are especially active during adolescence,and skin is at its oiliest

15. Holocrine Glands/Sebaceous Glands
Releases its secretions by disintegrating the “whole” cell and releasing “sebum”
Sebum is lipid-concentrated and is meant to lubricates the skin and slows bacterial growth. It keeps your skin soft and moist.

16. How does Acne form?
Your skin is covered in tiny wells called “pores” that sit on the hair follicles of your skin.
The overflow of sebum produced by the gland can clog the pore.
The clogged pore can house bacteria, which can lead to inflammation and redness.
Acne occurs in stages

18. How does acne form?
Whiteheads: are a type of acne that is not inflamed.
Originate below the skin the sebum is evident outside of the skin
Skin cells, oil and bacteria create a mixture (sebum) that clogs the skin surface (pores) and the underlying duct

19. How does acne form?
Blackheads: if the sebum continues to accumulate and dries, it darkens and becomes a blackhead
Evident on the skin surface
Blackheads are not inflamed

21. Why does acne form?
There are different types of acne that have different intensities and durations

22. Why you shouldn’t pop your pimples:

23. Apocrine Glands
Found in the armpits, the genital area and around the nipples.
They release their contents into the surrounding hair follicles . They don't release secretions until after puberty
Involved in emotional sweating, most active in times of stress and anxiety

24. Apocrine Glands
Releases secretions from the apex of the cell or the “top of the cell”, which breaks off to release a mixture of proteins, lipids and steroids.
Their secretions are odorless, but can take on an unpleasant odor if bacteria live on them.

25. Merocrine/Eccrine Glands
Found virtually everywhere in the skin (i.e palms of your hands, soles of your feet)
Release watery-salty sweat by exocytosis (the budding off of the cell membrane)
Does not dump its excretion into surrounding hair follicles, but into funnel-shaped pores
Help with evaporative cooling and eliminate waste products

26. Video on Tattoos: