1. Physiology Intro: The Integumentary System Unit 8 – Powerpoint #1
Honors Biology
Unit 8 – Powerpoint #1
Chapter 35 /36

2. What is Physiology?
Physiology is the study of the functions of living organisms and their parts

3. What is Homeostasis
The ability to maintain a constant internal environment

4. Eleven Organ Systems
For example the Skeletal System which includes your bones, cartilage, ligaments and tendons. Try to think of as many organ systems as you can. Write them on the lines provided.

5. The Eleven Organ Systems
Skeletal
Muscular
Circulatory
Respiratory
Digestive
Nervous
Reproductive
Excretory
Lymphatic/Immune
Endocrine
Integumentary

6. Today: Integumentary System
Structures: skin, hair, nails, sweat glands and oil glands.
Functions:
Barrier against infection and injury (including UV protection)
Helps regulate body temperature
Prevents H2O loss
Waste excretion
Vitamin D synthesis

7. Fun Facts Where is your thinnest skin located? Thickest?
Eye lids (thinnest) soles of feet (thickest)
How many skin cells do you shed in a minute?
About 30,000-50,000 dead cells
How many pounds of skin do you loose per year?
8-10 lbs
How much of the dust in your home is dead skin cells?
50% (Globally, dead skin accounts for about a billion tons of dust in the atmosphere)
Does sweat smell?
No, it’s the bacteria 
How much bacteria is on your body?
1,000 different species AND 1,000,000,000,000 individual bacteria

8. The Largest Organ Skin is 12-15% of body weight
15-20 sq. ft ( sq. meters)
Some organisms, such as insects, and some amphibians, use the integumentary system for respiration

9. Epidermis Dermis 2 Layers The skin is made of 2 main layers
Below the dermis is subcutaneous fat (hypodermis) that insulates body

10. Skin: The Layers

11. Epidermis: First layer
Structure
Outer layer are flattened, dead cells, inner layer living
As lower cells do mitosis they move and push others to surface of skin
As move up, become flattened and make keratin (tough, fibrous protein)
Takes days for new cells to reach the top
Contain nerve endings but no blood vessels

12. Epidermis

14. Epidermis: First layer
Function
1) Water resistance (keratin filled dead cells)
2) Protective layer against biological/ chemical assault
3) Contains MELANOCYTES (Produce pigment MELANIN which protects from UV) (will talk more about later)
4) Contains Merkel cells – attached to nerves and detect touch
5) Contains Langerhans cells –guard against toxins, microbes and other pathogens that penetrate the skin. If detected, alerts immune system

15. Epidermis

16. Skin: Dermis
Found beneath the Epidermis

17. Dermis: Second layer Structure
Made of strong, flexible connective tissue
Contains:
Collagen
Nerves
Blood vessels
Lymph vessels
Hair follicles
Sweat glands
Muscles (attached to hair follicles)

18. Dermis: Second layer Function
1) Contains Sweat glands (3000/ in2) these:
-maintain homeostasis- regulates body temp
-Release various wastes from bloodstream
-Mammary glands and ear wax glands are modified sweat glands
2) Contains Sebaceous (oil) glands (2 per hair)
These glands release SEBUM keeping the epidermis and hair flexible and waterproof
3) Contains many sensory cells
4) Gives skin its elasticity and strength (collagen)

19. Skin color 2 types of melanin
Skin color is due mainly to the pigment MELANIN (made by melanocytes in the epidermis)
2 types of melanin
Eumelanin (comes in brown and black)
Phomelanin (pinkish-red)

20. Skin Color
Darker skin is due to kind and amount of melanin produced (everyone has relatively similar numbers of melanocytes)
UV rays stimulate melanocytes to make more melanin (causing tanning)
Melanin protects skin cells under it from harmful UV B rays

21. Melanoctyes

23. Skin Markings
Skin Markings: Freckles: Flat, melanized patches Varies with heredity or sun exposure Moles: Elevated patches of melanized skin, with hair

24. This is your hair, and yes that is bacteria 

25. Hair Made of Keratin Hair covers almost every exposed surface.
Hair growth is determined by hormones
You are born with as many hair follicles as you will ever have
Hair is used for protection. From the sun, or dirt
Hair color
Depends on kind (red, brown, black) and amount of melanin
Hair Texture
Related to difference in shape of hair
Straight = round, Wavy = oval, Tightly curly = flat

26. Hair differences
Scanning electron micrograph of a hair fiber from a Caucasian blonde female (above) and an Asian male (below). The overlapping cells of the cuticle are readily apparent on both fibers.

29. Nails Scale-like modification of the epidermis
Made of thin, dead, scaly cells, packed together
Protect the ends of the fingers and toes
Produced by the nail root: an area of rapid mitosis
Fingernails grow 1mm/week, toenails slower

31. Disorders Basal Cell Carcinoma Squamous Cell Carcinoma
Skin Cancer
Basal Cell Carcinoma
Most Common – 99% fully cured
Squamous Cell Carcinoma
Lower layer of epidermis
Induced by the sun
Malignant Melanoma
Cancer of pigment cells = melanocytes
Rare – 1% of skin cancers
Poor chance of cure
Often begins with moles

32. What not to do:

33. Burns: 1st Degree
Inflamed, red skin – surface of epidermis is shed

34. 2nd Degree Blisters form as fluid builds beneath epidermis
Burns epidermis and part of dermis

35. 3rd Degree Epidermis & Dermis is destroyed
Catastrophic loss of fluids (dehydration)
Highly susceptible to infection
Look up photos online if you would like (they can be pretty graphic)

36. Aging Hair Thin and gray as melanocytes die, and mitosis slows
Oil Glands
Sebaceous glands atrophy (shrink) = Skin and hair become drier
Skin Layers
Mitosis slows, Collagen lost from dermis = Skin becomes thin and translucent,
Loose and sagging as elastic fibers are lost in dermis
Fewer blood vessels = More bruising, slower healing
Age Spots – accumulation of pigment cells

37. Interesting Websites on Integumentary system
Interesting Facts
Skin Anatomy and Effects of Aging
Skin Cancer Investigation