1. Chapter 6 Skin and the Integumentary System
Composed of several tissues
Protective covering
Retards water loss
Houses sensory receptors
Contains immune system cells
Synthesizes chemicals

2. Skin Cells
help produce ___________ needed for normal bone and tooth development
some cells (keratinocytes) produce substances that simulate development of some ______________

3. Layers of Skin Epidermis Subcutaneous layer beneath _______
not part of skin

4. Epidermis lacks ____________ keratinized
thickest on ______ and ___________ ( mm)
melanocytes provide ______________
rests on basement membrane
stratified squamous

5. Production of new cells is balanced with the loss of _______ cells
Protects underlying tissues against _______ loss, mechanical injury, and the effects of harmful chemicals
Epidermal cells __________ and die as they are pushed to the surface

6. Epidermis Layers of Epidermis stratum __________ (dead cells)
stratum lucidum
stratum granulosum
stratum spinosum
stratum ___________ (reproduce and grow)

8. Dermis on average 1.0-2.0mm thick contains dermal papillae
binds epidermis to _____________
irregular _____ connective tissue
muscle cells
nerve cell processes
specialized sensory receptors
blood vessels
hair ___________
glands

10. Subcutaneous Layer hypodermis loose _________ tissue __________ tissue
insulates
major blood vessels

11. Hair Follicles epidermal cells tube-like depression
extends into dermis
_______ root
________ shaft
_________ papilla
_______ epidermal cells
melanin
arrector pili muscle

12. A hair usually ________ for a while, rests, and then is replaced by a new hair.
Hair color is determined by _______ that direct the type and amount of pigment epidermal melanocytes produce
A bundle of smooth muscle cells forms the _________ ______ muscle and attaches to each hair follicle
One or more _________ glands are attached to each hair follicle

14. Nails protective coverings nail ______ nail ______ lunula
made of specialized
_________ cells that
keratinize

15. Sebaceous Glands usually associated with hair __________
holocrine glands
secrete _______
Excess _________ causes acne
absent on palms and _______

16. Sweat Glands sudoriferous glands widespread in skin
originates in deeper dermis
or hypodermis
_________ glands
_________ glands
ceruminous glands
mammary glands

17. Eccrine sweat glands Most numerous
Found on the forehead, neck, back, palms, and soles
Respond to ___________ body temp or emotional stress
_________ and sebaceous gland activity decreases with advancing age
Sweat is mostly water with ________ and waste products

18. Apocrine Sweat Glands Become ________ at puberty
Located in the _______ regions (armpit), groin, and around the nipples

19. Ceruminous glands are modified sweat glands that secrete __________
Mammary glands are modified sweat glands that secrete _________

21. Regulation of Body Temperature
Regulation of body temperature is vital because heat affects the rates of metabolic reactions. Normal temperature of deeper body parts is close to a set point of ____°C (98.6°F). Skin plays a key role in body temperature homeostasis.

22. Heat production and loss
Heat is a by-product of ________ respiration.
The most active cells are ________ and heart muscle cells and the liver.
If body temperature rises above normal:
-more blood enters ________ blood vessels (vasodilation).

23. If body temperature rises above normal:
_______ blood enters dermal blood vessels (vasodilation).
deeper blood vessels contract (vasoconstriction) diverting blood
to the surface and the skin reddens

24. heat is lost to the outside by:
____________ - rays move from warmer to cooler surroundings (primary way)
____________ - heat moves from warmer objects to cooler objects it is touching
____________ - heated air moving away from the body
____________ - fluid evaporates from the surface carrying heat away (sweating)

25. If the body temperature drops below normal:
_________ blood vessels constrict, causing the skin to lose color
________ glands become inactive
if heat is lost excessively, skeletal muscles involuntarily contract increasing cellular respiration and producing additional _____.

26. Problems in Temperature Regulation
________________ – abnormally high body temperature
________________– abnormally low body temperature

27. If the air is saturated with water, ______ may fail to evaporate, and body temperature may remain elevated (_____________)
Symptoms may begin with headache, dizziness, nausea, muscle cramping, and may lead to major organ failure
Lack of sweating – medical emergency

28. ________________ is lowered body temperature.
Symptoms begin with shivering, and leads to mental confusion, lethargy, loss of reflexes and ,consciousness, and eventually major organ failure

29. Skin Color
All humans have about the same number of melanocytes. Skin color differences are due to the amount of __________ produced

30. Genetic factors
_________ that control melanin production are inherited.
Dark skin is due to genes that cause large amounts of _________ to be produced
Lighter skin is due to genes that cause lesser amounts of ________ to form.
Mutant genes may cause a lack of melanin in the skin called _____________.

31. Environmental factors
Sunlight, ultraviolet light, and ___ rays darken existing melanin and stimulate _____ melanin production temporarily darkening the skin.

32. Physiological factors
If blood is well oxygenated hemoglobin (blood pigment) is bright _____ causing the skin of light skinned people to appear pinkish.
If _______ content of blood is low hemoglobin is dark red and the skin appears _________ (cyanosis).
Dilated blood vessels can cause skin to redden

33. ____________ blood vessels cause a loss of reddish color.
___________ in the subcutaneous layer may cause the skin to appear yellowish.
• Disease may affect skin color.

34. Healing of Wounds and Burns
Skin injuries trigger ____________. Blood vessels dilate forcing fluids to leave and enter the damaged tissue. The affected area becomes red, warm, swollen, and tender.

35. Cuts
A shallow cut in the epidermis is filled in by reproducing epithelial cells.
Deeper cuts into the dermis or subcutaneous layer cause a clot to form.
platelets become entrapped in _______ fibers (fibrin).
tissue fluids seep into the area
blood clot and dried fluids form a _______

36. ___________ begin to form new collagenous fibers that bind edges of the wound together
blood vessels extend beneath the scab
phagocytes remove ________ cells
a _______ where connective tissue replaces skin may appear

37. granulations (new blood vessel branch & fibroblasts) may form in large open wounds

38. Healing of Cuts

39. First degree burns (superficial partial-thickness burn)
only burns the ____________
heals quickly with no scarring
the area is warm and red.

40. Second degree burns (deep partial-thickness burn) –
destroys some ________ and ________
________ appear
area becomes moist and firm and varies in color from dark red to waxy white

41. healing depends on the accessory organs that survive
skin usually recovers with no scar tissue unless an _________ occurs.

42. Third degree burns (full-thickness burns)
destroys the ________, ________, and the
____________ organs of the skin
injured skin may appear dry and leathery and varies in color from red to black to white
healing only occurs from epithelial cells growing inward from the margin of the burn

43. may require skin grafting:
____________ - thin layer of skin from unburned area is removed and transplanted in injured area
___________ - cadaveric skin is used to cover injury
skin substitutes
- amniotic and artificial membranes human skin cultures
- grow in lab and transplant
extensive scarring

44. Rule of Nines

45. Life Span Changes Melanin production slows Skin becomes scaly
_______ thins
Number of _____ follicles decrease
Nail growth becomes impaired
Sensory receptors decline
Body temperature unable to be controlled
Diminished ability to activate Vitamin ____
Skin becomes scaly
Age spots appear
________ thins
Dermis becomes reduced
Loss of ______
Wrinkling
Sagging
______________ glands secrete less oil

46. Clinical Application Acne Vulgaris most common skin disorder
sebum and epithelial cells clog glands
produces whitheads and blackheads (comedones)
anaerobic bacteria trigger inflammation (pimple)
largely hormonally induced
androgens stimulate sebum production
treatments include antibiotics, topical creams, birth control pills