1. The Integumentary System

2. Components Skin Nails Hair follicles Sebaceous glands(oil)
Sweat (sudoriferous) glands

3. Functions of the Skin Protection (1st line of defense)
Regulates body temp.
Conserves water inside body
Contains sensory receptors
Makes biochemicals
Excretion of wastes
*Skin is the largest organ of the body

4. Layers of Skin Skin has 3 layers 1. Epidermis - outer layer
2. Dermis – middle layer
3.subcutaneous/hypoderm- bottom/deepest layer

5. 1. Epidermis Outer layer of skin cells
Avascular- lacks blood vessels, fed by diffusion
Acts as a mechanical barrier
Made of many layers of cells
Top cells dead
Bottom layer alive- multiply and new cells are pushed upward
(EX-”Ashiness” is caused by this layer of dead skin cells being very rough and raggedy.
DUST you see around is made up of dead skin cells! )

6. Epidermis
Keratinization- process where keratin develops in a cell, which hardens it, and makes the cell layer waterproof
Contains melanocytes- cells which contain the pigment melanin
Difference is skin color is due to % of melanin in the cell .( We all have the same # of cells, just produce a different amt. of melanin.)
Amt. of melanin increases with UV light exposure
Too much exposure=melanoma (skin cancer)

7. The Skin FG04_02.JPG Title: Components of the Integumentary System
Notes: Relationships among the major components of the integumentary system (with the exception of nails, shown in Figure 4-15).
Keywords: integumentary system, cutaneous, epidermis, dermis, papillary layer, reticular layer, hair follicles, exocrine glands, nails

8. Layers of Epidermis 5 layers “Cows Love Grass So Badly”
Stratum corneum (corny/scaly)
Stratum lucidum (palms of hands, feet, absent in thin skin)
Stratum granulosum(granular)
Stratum spinosum(spiny/prickly)
Stratum basale (base/bottom)
*1st degree burns

9. Epidermis FG04_03.JPG Title: The Structure of the Epidermis
Notes: A light micrograph through a portion of the epidermis, shows the major stratified layers of epidermal cells.
Keywords: epidermis, structure, layers, stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, stratum germinativum, dermis

10. 2. Dermis Thick layer under the epidermis Collagen, elastic layer
Vascular-Contains blood vessels
Oil glands (sebaceous)
sweat glands
Hair follicles
Nerves
Arrector pili muscle
*2nd degree burns

11. 3. Subcutaneous Layer AKA- Hypodermis
Contains Fat tissue in adipose cells
Thickens w/ weight gain
Stabilizes position of skin
Insulates(temp. regulation)
Larger branches of blood vessels
*3rd degree burns

12. Accessory Organs of the Skin
Hair/hair follicles
2. Sebaceous glands
3. Nails
4. Sweat glands

13. Hair Structure Found in Dermis of skin
Cells of hair follicle grow and develop in the blood vessels
As cells move upwards they become keratinized and die
Melanin – pigment that contributes to dark hair color

14. Smooth muscle attaches to follicle Raises hairs
Arrector Pili
Smooth muscle attaches to follicle
Raises hairs
Response to fright or cold
Pulls hairs upright to create a layer of warm air on surface of skin

15. Functions of Hair
Protection
Sensory perception
Thermoregulation (insulation)
-Minor role in humans (exception-
Hypertrichosis)

16. Hair Structure FG04_10A.JPG Title: Hair Follicles
Notes: Hairs originate in complex organs termed follicles. (a) A longitudinal section and a cross section through a hair follicle. (b) and (c) A section along the longitudinal axis of a hair follicle.
Keywords: hair follicle, longitudinal section, cross section, sebaceous gland, arrectory pili muscle, cortex, cuticle, internal root sheath, connective tissue layer, glassy membrane, external root shaft

17. Sebaceous Glands Connected to hair follicles
Secrete a waxy, oily substance (sebum)
Functions of Sebum-
-keeps skin soft
-keeps skin pliable
-keeps skin waterproof
Secretion increases at puberty

18. Sebaceous Glands FG04_13A.JPG Title: Sebaceous Glands and Follicles
Notes: The structure of sebaceous glands and sebaceous follicles in the skin.
Keywords: sebaceous glands, sebaceous follicles, structure, sebum, germinative cells

19. Nail Function and Structure
Protective covering on fingertip used for picking, scratching, grooming
Keratinized, stratifies squamous cells make nails hard
Nail root bed – area where new cells are formed

20. Sweat Glands Sweat glands Found just about everywhere on body
Dermis layer of skin
Produce sweat aka perspiration
Water, salt, wastes (toxins), urea, and uric acid
mL/day, up to 12 L/day
Function – cooling of the body, releasing scent, producing milk, ear wax

21. Sweat Gland Types
Eccrine and Apocrine, two types are different in size and the age they become active
Eccrine- most numerous type, found all over the body particularly on the palms, soles of the feet, and forehead, exits pores
Apocrine is mostly the armpits. They end in hair follicles instead of or pores.
modified- includes scent glands, mammary glands, ceruminous (produce ear wax), ciliary- eyelid

22. The skin also helps control body temperature- Homeostasis!
When you sweat, heat leaves the body through your pores.
When the sweat hits the outer surface of the skin, it is cooled by the air.
This lowers your body temperature.

23. Regulation of Body Temperature
Normal body temp- 37 C, F
Controlled by hypothalamus of brain
Amt. of heat produced is balance by the amt. of heat lost
Cellular chemical rxns create heat
Muscle contraction creates heat
Homeostatic response when exposed to an increase in temp. or a decrease in temp.
FG04_02.JPG
Title: Components of the Integumentary System
Notes: Relationships among the major components of the integumentary system (with the exception of nails, shown in Figure 4-15).
Keywords: integumentary system, cutaneous, epidermis, dermis, papillary layer, reticular layer, hair follicles, exocrine glands, nails

24. What happens if body temp. is too high?
Body has mechanisms to rid itself of excess heat-
Warmed blood reaches hypothalamus nerve impulses respond more blood sent to limbs  flushed skin
Vasodilation- blood vessels dilate, skin releases heat, hair lays flat
Activation of sweat glands- moisture allows more heat to be released
Outcome- Overall temp. decreases
FG04_02.JPG
Title: Components of the Integumentary System
Notes: Relationships among the major components of the integumentary system (with the exception of nails, shown in Figure 4-15).
Keywords: integumentary system, cutaneous, epidermis, dermis, papillary layer, reticular layer, hair follicles, exocrine glands, nails

25. What happens if body temp. is too cold?
Mechanisms to save heat and create heat in response to cold-
Thermoreceptors send signals to hypothalamus
Vasoconstriction- blood vessels constrict to reduce heat loss more blood in corepale
Deactivation of sweat glands
If temp. is still too low, muscles will contract (shivering) to create heat, hair stands up
Outcome- Increase in overall body and blood temp.
FG04_02.JPG
Title: Components of the Integumentary System
Notes: Relationships among the major components of the integumentary system (with the exception of nails, shown in Figure 4-15).
Keywords: integumentary system, cutaneous, epidermis, dermis, papillary layer, reticular layer, hair follicles, exocrine glands, nails

26. Table 5 - Hypothalamic Regulatory Center
Structures
When Body Cools
When Body Warms
Superficial blood vessels
Constricts
Dilates
Sweat glands
Inactivates
Activates

27. Veins Constrict (narrow)
Veins dilate (widen)

28. Controlling body temperature
Body temperature is controlled by the thermo-regulatory center in the ________. It is kept at 370C as this is the best temperature for __________ to work in. If the body becomes too hot then blood vessels _________ and sweat glands release ________. If the body is too ______ then blood vessels constrict and muscles start to __________.
Words – sweat, enzymes, cold, dilate, shiver, brain

29. Checkpoint What is the normal body temperature?
What part of the brain controls temp.?
How does the body respond to too much heat?
How does the body respond to cold temp.?
What type of muscle contracts to cause shivering?
What is the difference between vasoconstriction and vasodilation?
FG04_02.JPG
Title: Components of the Integumentary System
Notes: Relationships among the major components of the integumentary system (with the exception of nails, shown in Figure 4-15).
Keywords: integumentary system, cutaneous, epidermis, dermis, papillary layer, reticular layer, hair follicles, exocrine glands, nails