1. THE
INTEGUMENTARY
SYSTEM

2. Composed of: Skin Nerves Hair Pigment Sweat glands Muscles
Oil glands
Nails
Nerves
Hair
Muscles
Blood vessels
Fat

3. Skin Functions Protects deeper tissues from: Mechanical damage
Chemical damage
Bacterial damage
Thermal damage
Ultraviolet radiation
Desiccation

4. Skin Functions Aids in heat regulation
Aids in the removal of certain waste products: urea and uric acid (in sweat)
Identifies contact with an object or pain
Synthesizes vitamin D

5. Skin Structure EPIDERMIS
Made up of 5 external layer of epithelial tissue.
Often keratinized (meaning it contains a water-proof protein called keratin)
Made up of epithelial cells, melanocytes, and keratinocytes
The visible part.

6. Skin Structure DERMIS Is referred to as the “true skin”
Made up of two types of connective tissue
The superficial papillary layer made up of a loose arrangement of collagen and elastic fibers.
The deep reticular layer made up of densely packed collagen fibers with some elastic fibers.
Has large supply of:
blood vessels, sensory receptors (called corpuscles), and oil/sweat glands

7. HYPODERMIS Deep to the dermis Composed mostly of adipose tissue
The amount of fat varies depending on the body part.
Lots of fat: soles of feet, palms, lower back
Little fat: eyelids, anterior wrist, top of foot

8. Skin Structure

9. Melanin Pigment (melanin) produced by melanocytes
Melanocytes found in the epidermis
Amount of melanin produced depends upon genetics and exposure to sunlight

10. Skin Color is attributed to:
Melanin
Yellow, brown or black pigments
Carotene
Orange-yellow pigment from some vegetables
Hemoglobin
Red coloring from blood cells in dermis capillaries
Oxygen content determines the extent of red coloring

12. Freckles and moles are areas of melanin concentrations.
Melanin within cells migrates to the cell surface that is exposed to sunlight and “shades” the nucleus from UV light.
Excessive sun exposure breaks down melanin and can lead to genetic mutation (cancer).

13. The Glands of the Integument
Sebaceous glands
Sudoriferous glands
Ceruminous glands

14. Sebaceous Glands Produce oil Serves as a lubricant for skin
Kills bacteria on skin surface
Have ducts that empty into hair follicles
Glands become active at puberty

15. Skin Appendages Sudoriferous glands Produce sweat
Widely distributed in skin
Function
Helps dissipate excess heat
Excretes waste products
Acidic nature inhibits bacteria growth
Odor is from associated bacteria

16. Two types of Sudoriferous glands 1. Eccrine glands
sweat is released via a duct to a pore on the skin surface
most common sweat gland
makes the “clean” sweat
Sweat Composition
99% water
some metabolic wastes

17. sweat ducts empty into hair follicles
2. Apocrine glands
sweat ducts empty into hair follicles
found in axillary and genital areas
makes the “smelly” sweat
Sweat composition
water, proteins, and fatty acids.
Glands become active at puberty.

18. Nerves We have two different types of sense receptors in the dermis.
The ones closest to the epidermis are called Meissner’s corpuscles.
They identify temperature change, and when you come into contact with an object.
They sometimes have free nerve endings that detect pain.

19. These nerves are for identifying texture, pressure, and vibrations.
The sense receptors that are deeper in the dermis are called Pacinian corpuscles.
These nerves are for identifying texture, pressure, and vibrations.
Pacinian corpuscle

20. Blood Vessels
The dermal layer is the only vascular portion of the integument.
When it is hot, the blood vessels dilate allowing body heat to be released to the skin surface.
When it is cold, the blood vessels constrict holding in the body heat.

21. Hair Produced by a cluster of cells called a hair bulb.
Hair strands consists of hard, keratinized epithelial cells
The hair follicle is basically an indentation of the epidermis into the dermis.
It forms a “pocket” lined with cells that protect the hair as it grows.

22. Melanocytes surround the hair bulb and give hair its color.
The hair root is the part of the hair that is implanted in the skin.
The hair shaft is the portion of the hair that we see.

23. Integumentary Muscles
Attached to the hair follicle is a muscle called the arrector pilli.
When this muscle contracts, it causes goose-bumps and makes the hair stand up.
This smooth muscle contracts involuntarily and helps to keep us warm.

24. Appendages of the Skin Nails Scale-like modifications of the epidermis
Heavily keratinized
Lack of pigment makes them colorless, yet the body is pinkish due to blood vessels in the nail bed.

25. Nail Structures Free edge – the distal end of the finger nail
Body – central area; protects the nail bed
Root of nail – where growth originates; embedded deep to the proximal cuticle
Lunula – white, crescent area on the proximal end of the nail
Cuticle – proximal nail fold that projects onto the nail body
Nail Bed – the area of tissue underneath the nail.

26. Nail Structures