1. Ch 6 – Integumentary System
Notes

2. Describe what constitutes an organ.
What is an organ made of?

3. What does the skin do? Regulates temperature Protects Secretes waste
Synthesizes chemicals

4. Describe the largest organ of the integumentary system.
Skin
Skin is a HUGE organ! – If the skin of a 150-lb person were spread out flat, it would cover approximately 20 square feet.
Functions:
Homeostasis
Sensory receptors
Synthesizes chemicals
Protective covering
Excretes waste

5. Describe the structure and layers of the skin
Epidermis
Basement membrane
Dermis
Subcutaneous layer
Pg 118 – diagram
Quiz Monday!

6. Epidermis Top layer - “epi-” means upon. Stratified squamous tissue
No blood vessels
Deepest layer of epidermis – stratum basale (or stratum geminativum)
Nourished by dermal blood vessels
Produces new stratified squamous cells, pushes them upward, old cells die and shed

7. Epidermis Stratum lucidum is an extra layer on palms and soles
Older cells are keratinized – cytoplams fills with the protein keratin (tough and fibrous); accumulate in the outer layer called the stratum corneum
Stratum lucidum is an extra layer on palms and soles
No hair
Rate of cell division increases where skin is constantly rubbed or pushed, creating calluses or corns.

8. Epidermis – Skin Color
Melanocytes – produce melanin (dark pigment that produces skin color.)
Melanin absorbs sunlight which prevents DNA mutation.
Melanocytes located in the deepest part of epidermis.
People have roughly the same number of melanocytes, just different levels of melanin production and different sizes and distribution of pigment granules.
Melanin production is genetically controlled.
Pg 120 diagram and picture

9. Epidermis – Skin Color
Skin color can also be determined by some physiological factors as well:
Sunlight, other UV exposure, and X Rays can stimulate additional pigment production.
Blood oxygen – Well-oxygenated blood is red; Low- oxygenated blood is dark red.
Yellow veggies – contain beta-carotene pigment which turns skin orange-yellow.
Jaundice – High biliruben causes skin to turn yellow.

10. Dermis Uneven barrier between epidermis and dermis: dermal papillae.
Create fingerprints
Mostly dense connective tissue: collagenous fibers and elastic fibers
Blood vessels: supply nutrients to all skin (including epidermis) and regulate body temp.
Nerve cells are present (Pg 264)
Accessory structures

11. Describe the anatomy and physiology of each accessory structure of the skin.
Nails – protective coverings
Nail plate
Nail bed
Produced by epithelial cells that become keratinized
Lunula

12. Describe the anatomy and physiology of each accessory structure of the skin.
Hair follicles – tube-like depression from the surface downward.
Produced by epithelial cells
Contains the hair root
Hair shaft – dead, keratinized epidermal cells
Hair color – determined by genes which say how much and what type of pigment melanocytes produce
Eumelanin – brownish-black
Pheomelanin – reddish-yellow
Abinism – lack of color

13. Describe the anatomy and physiology of each accessory structure of the skin.
Arrector pili muscle – makes hair “stand on its end”
Sebaceous glands – holocrine glands that secrete oliy mixture called sebum to keep hair and skin soft and waterproof.
Sweat glands – exocrine glands that secrete sweat, salts, and other wastes through pores on the surface of the skin. Also develop scent.

14. More on Sweat Glands Eccrine glands Apocrine glands
Respond to changes in temperature
Most active on neck, forehead, and back
Active throughout life
Respond to emotions
Most numerous in axillary and groin
Become active at puberty

15. Explain how the skin helps maintain homeostasis.
Mainly through temperature control.
Hypothalamus controls the elements of the skin that regulate temperature.
Active cells in the body – the heart, muscles, etc – produce heat that must be released.
Temperature; hypothalamus;

16. Explain how the skin helps maintain homeostasis.
Heat can be lost in three ways:
Radiation
Sweating
Dilation of blood vessels
Heat can be retained in three ways:
Constriction of blood vessels
Deactivating sweat glands
Shivering
Radiation; sweating; dilation; constriction; sweat glands; shivering

17. adipose tissue
arrector pili muscle
basement membrane
blood vessel
dermis
Epidermis
hair follicle
hair shaft
nerve cells
sebaceous gland
stratum corneum
subcutaneous layer
sweat gland
sweat pore

18. Describe how wounds are healed.
Inflammation – Blood vessels dilate, becoming red and swollen.
Epidermis - mitosis
Dermis – clots -> scabs -> connective tissue
Large wounds – Similar to dermis, but more likely to leave scars.
Blood vessels; mitosis; scabs; scars

19. Subcutaneous Layer Made mostly of adipose tissue.
Contains the major blood vessels.

20. Discover to Learn Pg 121 Skin Cancers Cutaneous Carcinomas
Cutaneous Melanomas
Discover to Learn
Pg 121

21. Skin Disorders Skin disorder mixup! – pg 127 & 129
For each skin disorder, share the following:
Cause
Symptoms/Signs
Treatments/Cures
Picture/Pictures
Students will each choose a different skin disoder. In pairs, they will research and prepare for both of their disorders. They have 15 minutes to prepare, then they will take turns sharing with the class.

22. Journal 2/18
Heat exhaustion may result in fatigue, dizziness, muscle cramps, nausea, tachycardia, agitation, intense thirst, and profuse sweating.
What is the body already trying to do to combat this condition?
What else would you recommend to someone in this situation? (2-3 things)