1. Dermis Just deep to epidermis Two layers Collagen and elastin
Papillary layer
Reticular layer
Collagen and elastin
Dermal blood supply
Nerve endings
Some muscle tissue
Glands
Hair and nails

2. Papillary Layer Papillary Reticular
Contains dermal papillae (hence papillary)
Many capillary loops (feed the epidermis)
Reticular
Base of hair and nails
Nerve endings
Glands

3. Hair Anatomy Shaft – shows above skin Root – below / in the skin
Follicle - where hair attaches and grows from (clear part when pulled out)
Hair matrix – group of cells that cause growth of hair (they create more cells, causing the others to move upward = growth)

4. More hair…. The hair that you groom daily (shaft) is actually dead
keratinized cells.
Each hair follicle has an associated bundle of smooth muscle, the arrector pili muscle. This muscle inserts with one end to the papillary layer of the dermis and with the other end to the hair follicle.
This makes your hair stand up on its end.

5. Hair Color and Texture – fun facts
Hair color is determined by the amount and type of melanin present.
Melanocytes become less active with age. Gray hair is a mixture of pigmented and non-pigmented hairs.
Red hair results from a a modified type of melanin that contains iron.
The shape of the hair shaft determines texture.
Round shaft – straight hair
Oval shaft – wavy hair
Flat shafts – curly or kinky hair
**Perms use chemicals to flatten shafts and makes hair curly.
Alopecia is the term for hair loss.

6. Nails Plates of cells with hard keratin
Protect distal ends of phalanges
Cells are keratinized in the nail root
Nail growth occurs in the lunula
Nail matrix – group of cells responsible for growth
The cuticle is a fold of stratum corneum on the proximal end of nail

7. Click here to copy and paste a Picture of the skin and nail here.

8. Glands Exocrine glands = “EXIT” the body “Ex”ocrine
Sweat, Oil, Ear wax
All that relate to skin
Endocrine glands = release contents within the body
hormones

9. Sebaceous glands They secrete the sebum (seb = oil) an oily product.
Sebum is usually secreted into a hair follicle.
Sebum is a natural skin cream:
prevents excessive evaporation of water from the skin,
keeps the skin soft
contains a bactericidal agent that inhibits the growth of certain bacteria.
Sebaceous glands are scattered all over the surface of the skin except in the palms, soles and the side of the feet.

10. Homeostatic Imbalance:
Pimples = bacteria in oil glands
Blackhead – sebaceous gland is blocked and the blockage dries up (oxidized)
Whitehead – Sebaceous gland blocked / pus

11. Sweat Glands Eccrine – Found all over the body
secretes directly to the surface of skin via pores
Main function: evaporative cooling
Apocrine –
Activated during puberty
Located in the axillary region, pubic region, and mammary region.
Secrete onto hair follicle (unlike eccrine)
A LOT stronger / potent than eccrine sweat glands

13. Other exocrine glands Mammary glands Ceruminous Glands
Related to apocrine glands
Secretes milk
Triggered by hormones
Ceruminous Glands
Modified sweat glands
Produce cerumen (ear wax)
Helps trap foreign particle from entering

14. Sensory!! (nerve endings)
Meissner’s corpuscles – (tactile)
sensitive to light touch
found in papillary layer
Pacinian corpuscles – (lamellated)
deep pressure and vibration
found in reticular layer

15. More Fun Facts!! House dust is mainly skin flakes!
If you laid out all your skin on a flat surface, it would have an area of about 2 square meters.
Skin weighs about 2.5 kilograms - the largest organ in the body.
What hurts if you pull it, but doesn't hurt if you cut it? Your hair, of course!
Skin is elastic - it springs back into shape when stretched. Some medicines (estrogen, nicotine) can pass through the skin, but others cannot (insulin). Why is that? Because only fat-soluble substances can enter the skin, not water-soluble ones.
Your hair stands on end and you develop 'goose bumps' because there are tiny muscles attached to the hair follicles and they contract when you are frightened or cold.