1. Integumentary System:
Ch. 4
Integumentary System:
The Skin and Its Parts

2. Applied Learning Outcomes
1. Use terminology associated with the Integumentary system
2. Learn about skin structure, function, appendages, glands, and care
3. Understand the aging and pathology of the Integumentary system

3. Case Study Investigation – Ch. 4
You are observing an elderly woman who is seeing
a personal trainer as part of her rehabilitation
therapy. The woman was hospitalized for
problems associated with obesity &
high blood sugar. She is now going
through an exercise program to helpb
bring her back to health. While
working out, one of her socks rolled
down exposing the lower part of her
leg. A glance at the side of her left
leg, revealed a large, shiny, deep red

4. sore. The sore had a dark margin, like tanned skin.
Parts of it looked as if you could see right through
to the muscle. The woman saw your face reacting
to the sore and kindly said, “Don’t worry about
that, it doesn’t cause me any pain.”
Part of the personal’s trainer’s
responsibility is to pay attention to
the pathology that can be worsened
by the patient’s rehab. By the end
of this chapter you will be asked to
determine the possible problems
causing this skin condition.

5. Human Skin Trivia
skin – largest organ in body (25sq.ft or 16% of your body weight)
lose an avg. of hairs/day
stretchable & washable
avg. scalp has 100,000 hairs
shed 40lbs of skin/lifetime on avg. (1 layer every 24 hrs)
body loses 30,000–40,000 dead cells/min.
45 miles of nerves in skin
blondes have more hair than brunettes

6. Did You Know? Chaetophobia is the fear of hair.
Tonsurphobia is the fear of haircuts.

7. Did You Know?
Hair generally grows at a rate of approximately 3/16” per day, or approximately ½” per month.

8. Did You Know?
Hair is naturally colored by pigment granules (melanin) in the cortex whereas dyed hair has melanin in the cuticle as well as the cortex.

9. Overview The skin is the largest organ is in
the body and is composed of:
Blood vessels
Nerve
Hair
Nails
Skin
Glands
Receptors

10. Overview
Inherent: qualities an organism is born with
ex. Genes for making nails only turn on in
the upper tips of the fingers and toes
Adaptive: ability of an organism’s genes to respond to environmental changes
ex. calluses, suntan, skin stretches as the body grows and shrinks back after a woman gives birth

11. Functions of Integumentary System
Protection - against environment (UV rays, microbes); and self-repairs cuts & burns
Heat regulation – maintain homeostasis (blood vessels)
Water resistant – prevents water from flushing out important nutrients
Sensation – receiving stimuli from the environment (receptors)
Absorption - can receive O2, N2, medicine
Waste excretion – can excrete CO2, urea, sweat
Synthesis of Vitamin D – Vit. D helps maintain normal blood calcium & phosphorus

12. 3 Major Layers of the Skin
Epidermis
a. stratified squamous tissue (epithelial)
b. strong & waterproof (keratin)
Dermis
a. dense connective tissue
b. contains blood, sweat
& oil glands
3. Hypodermis (subcutaneous)
a. adipose tissue
anchors skin (E & D)
to underlying organs

13. Microscopic View Epidermis - get a new one every 25-45 days
- melanocytes (melanin cells)
- keratocytes (keratin cells)
Dermis
- functional layer
Hypodermis / Subcutaneous
- adipose tissue
Microscopic View

14. 5 Layers of the Epidermis
OUTSIDE THE BODY*****
1. Stratum corneum
(dead cells & melanin
which gives skin color)
2-4. middle layers
(protein keratin
provides strength)
5. stratum germinativum
(living & dividing cells)
DERMIS*****

15. Why don’t we bleed when we shave??
The epidermis is AVASCULAR, meaning it has no blood supply of its own.
You only bleed if you cut deep enough to reach the dermis.

16. Dermis functional layer
contains blood vessels, sweat & oil glands, hair follicles, muscle fibers, nerve endings & elastic fibers
dermal papillae  finger-like projections of the dermis that
bind epidermis & dermis
form ridges & grooves that create fingerprints

17. Dermal
papillae

18. Hypodermis (subcutaneous)
composed of adipose tissue & elastic (connective) fibers
anchor skin to underlying fascia (tissue that covers muscles, skull & some organs)
major blood vessels & nerves branch upward into the dermis
absent/thin in eyelids, penis, scrotum, & nipples; responsible for increase in breasts & hips in females

19. Subcutaneous Injection
ideal site for rapid & relatively pain free absorption of injected material (i.e. insulin/
flu shot)
using a
hypodermic
needle

20. Concept Check Questions 1-3
1. List 5 major components of the Integumentary
system?
blood vessels, receptors, glands, nails, nerves, & hair
2. Distinguish between inherent and adaptive
characteristics. Give an example of each.
Adaptive – cause changes in skin that adjust the structure of skin to environmental conditions (tanning)
Inherent – structures that appear at birth (nails)
3. List 5 main functions of the Integumentary
system? protection (melanin), heat regulation (adipose tissue, blood vessels, sweat), absorption (blood vessels, pores), water-resistant (keratin,oil), sensation (receptors), waste excretion (pores, sweat), makes Vit. D (melanin)

21. Concept Check Questions 4-6
4. What are the 3 layers of skin from superficial to
deep? epidermis, dermis, hypodermis/subcutaneous
5. What kind of tissues can be found within each
layer of skin?
epidermis  stratified squamous (epithelial)
dermis  connective tissue
hypodermis  adipose & connective tissue
6. How do the 5 layers of the epidermis differ? Be
specific.
stratum corneum  dead cells and melanin for color
middle layers  keratin for strength
stratum germinativum  living and dividing cells

22. Concept Check Questions 7-9
7. Why don’t we bleed when we shave usually?
When would you see blood?
The epidermis is avascular – doesn’t contain any blood
vessels; only bleed if you reach dermis
8. Why is the dermis considered the “functional”
layer?
contains blood vessels, receptors, glands, muscle, nerve
endings
9. Where are dermal papillae found AND what 2
functions are they responsible for?
Found in dermis; 1) connects the dermis to the epidermis
2) create fingerprints

23. Skin Appendages assist skin with its functions glands nerves nails
assist skin
with its
functions
glands
nerves
nails
hair

24. Blood Vessels
expand/contract according to internal body temperature of body
1. warm body blood flow increases heat leaves
2. cold body
blood flow decreases
heat stays
3. sweat evaporation
 lowers body
temperature

25. Glands 3 types of glands commonly found in skin
Cerumenous glands (wax)
Sebaceous glands (oil)
3. sweat
a. apocrine sweat glands
b. eccrine sweat glands

26. Ceruminous Glands produce cerumen or ear wax that line ear canal
surrounded
by small hairs
collects dirt
& dust and
carries it out
of the ear

27. Sebaceous Glands attached to hair follicle
produces sebum, an oily secretion
sebum lubricates hair and surface of skin to prevent them
from drying
out

28. Sweat Glands produces sweat through pores 2 types a) Apocrine:
made of protein, fat,
etc.
responsible for body
odor
found in armpits,
naval, groin &
areolae (secrete fat
Into milk ducts)

29. Apocrine Sweat Glands
inactive till puberty & taper off in activity in elders
secretions contain pheromones (play a role in courtship & social behavior); dogs are notorious for sniffing these secretions
secretions are thicker, stickier and produce more odorous sweat  bacteria break sweat
down into acids
found deep in dermis and secrete
fluid into tiny canals of hair follicles

30. b) Eccrine:
found everywhere;
concentrated in armpits,
forehead, palms & soles of
feet
composed of salt
& H20  activity, amount &
distribution
is genetically determined
not as deep in dermis and
secrete into pores

31. Eccrine Sweat Glands
allow chemicals causing food odors leak out of the body
bacteria feed off nutrients in sweat  causing odors
antiperspirants reduce amont of sweat produced by glands  reduce dampness & odors
(-) charged ingredients repel (-) charged sweat molecules

32. Nerves Sensory receptors: communicate information from the environment
to the body
found in
all skin layers;
concentrated
in dermis &
fascia

33. Types of Sensory Receptors
Free nerve endings:
detect pain
in the epidermis

34. Types of Sensory Receptors
Meissner’s corpuscles:
in dermis
detect
touch
dermal
papillae
Also 
Krause end bulbs (cold temp.)

35. Types of Sensory Receptors
Pacinian corpuscles:
deep in dermis &
hypodermis
detect strong
pressure
(vibrations)
also  Ruffini
receptors

37. Nails nail root lies beneath cuticle (skin fold)
keratocytes in nail root move up, die & flatten  forms
nail body
lunula- moon
shaped whitish area
nails grow 1/8 in/mo.
faster than toenails

38. Hair
each strand of hair grows from a hair follicle (inward protrussion of epidermis)
hair papilla (base
of follicle) has its own
blood & nerve supply
hair shaft - dead,
hardened, keratinized
stratum corneum-like
cells

39. Layers of Hair 3 layers  cuticle, cortex & medulla
cuticle  thin, colorless, protects cortex & scales point toward tip; large in humans
cortex 
strength, color
& texture
medulla 
only present in
thick hair; small
or non-exsitent in humans

40. Hair Structure Cuticle – outer coating composed of overlapping scales
Cortex – protein-rich structure around the medulla that contains pigment
Medulla – central core (may be absent)
The structure of hair has been compared to that of a pencil with the medulla being the lead, the cortex being the wood and the cuticle being the paint on the outside.

42. Hair color determined by melanin amount & location determines color 
genetically controlled
arrector pili muscle
(smooth muscle) attachs
to hair follicle  causes
goosebumps (traps heat)

43. Drugs & Hair capture many chemicals (drug/poison)
that pass through blood
advantages: 1) goes
back months not days
2) non-invasive, 3) holds
up in court
disadvantages: 1)
expensive, 2) takes time
to get results

44. Stages of Hair Development:
Root must be present in order to test hair evidence for DNA
Anagen: growing
Catagen: at rest
Telogen: dying

45. Habits & Hair Loss hair loss is a slowing down of hair growth and
replacement
physical stress is a major cause of hair loss (childbirth,
illness, injury, pregnancy, and too much exercise
when body has to use its energy to cope with stress to
places hair growth as a lower priority
malnutrition and under-nutrition (diets low in amino
acids)
increase in male hormones
tight braids or ponytails might also pull off hair faster
than it can be replaced
excessive hair combing
emotional stress seems to accelerate growth

46. Concept Check Questions 10-12
10. What are skin appendages? Provide 4 examples.
- assist skin perform functions; hair, nails, glands, muscles, nerves
11. The dermis has the ability to regulate heat.
Describe 2 ways the dermis does this.
When hot  BV expand to release heat; releases sweat
When cold  BV contract to retain heat.
12. What do ceruminous & sebaceous glands produce
and how do these secretions differ in function.
- ceruminous glands  cerumen (wax)  clean ear
- sebaceous glands  oil (fats)  lubricate skin & hair

47. Concept Check Questions 13-15
13. Describe how appocrine & eccrine glands differ in
location and what they secrete.
- appocrine – secrete odorous sweat-like material; armpits, genitals (can contain pheromones)
- eccrine – secrete H2O, salts, ammonia; all over the body
14. What is the general function of nerves/receptors
in the skin? Name 3 & state what each detects.
communicate info from environment to body
- free nerve endings  pain Meisners corpuscletouch
- Pacinian corpuscle  pressure
15. Describe the differences btwn the 3 layers of hair.
- cuticle – outer layer; protects cortex & medulla
- cortex – middle layer; contains pigments; provides strength
- medulla – inner layer; usually only present in thick hair

48. Concept Check Questions 16-18
16. Why doesn’t a hair cut hurt, but pulling a hair
out of the head does?
- visible hair is made out of dead cells; hair root is living
17. What does the arrector pili muscle attach to and
what’s its function?
hair; allows hair to stand erect and trap in hot hair
18. What are the advantages & disadvantages of the
testing hair samples for drugs?
Advantages – 1) detects up to months not days, 2) holds
up in court, 3) non-invasive
Disadvantages – 1) expensive, 2) takes a long time to get
results

49. causes skin to lose ability to maintain homeostasis majority of
Burns
causes skin to lose ability to maintain homeostasis
majority of
burnssun
exposure &
cooking accidents
other causes
chemicals,
electricity, fires
& steam

50. 1st Degree  superficial damage; reddening and swelling
Types of Burns
1st Degree  superficial damage; reddening and swelling
chemicals, steam, flame
heat & mild sun exposure

51. Types of Burns
2nd Degree  stratum germinativum & dermal papillae damaged; blisters, fluid buildup, painful, long healing time;  longer exposure to previous factors

52. Types of Burns
3rd Degree  stratum germinativum not available for healing; dermis, adipose, muscle, nerve & bone damage;  excessive exposure to previous factors

53. Rule of Nines: method to determine extent of a burn injury

54. Wellness and Illness over the Life Span
Skin pathology can be categorized as:
degenerative
(diseases that progressively deteriorate skin)
genetic
(inherited; mutations)
infectious
(contagious, microorganisms)
Intrinsic: aging caused by the natural decline of cells
Extrinsic: aging caused by environmental factors (disease, pollution, sun exposure)
Degenerative: refers to diseases that progressively deteriorate tissues
-examples include skin cancer, moles, skin tags
Genetic disorders include acne, psoriasis, spider veins
Infectious diseases include impetigo, ringworm, warts

55. Degenerative Skin Disorders
freckles or solar lentigene (age spots) 
sun exposure
dermatitis (eczema)
skin inflammation
caused by allergic rxn
or irritant

56. Degenerative Skin Disorders
skin cancer  has an underlying genetic
component
moles 
flat squamous-
cell tumors;
heavily
pigmented by
melanocytes

57. Degenerative Skin Disorders
skin tags  soft, colored, knob-shaped tumors that grow out of skin (neck, armpits, body); surgery can easily remove

58. Genetic Skin Disorders
acne, cysts, boils 
hormonal changes causes
overproduction of sebum
around hair follicles
psoriasis  inflammation
of skin and increased skin cell
production; dry, itchy;
environmentally trigged??

59. Genetic Skin Disorders
port wine stains
& spider veins 
common birthmarks
vitiligo  white
spots on skin;
decrease in melanin
production (immune
attack on melanocytes
???)

60. Infectious Skin Disorders
MRSA  caused by Staphylococcus aureus bacteria; produces destructive secretions that erode and inflame skin

61. Infectious Skin Disorders
Ringworm (tinea)  skin fungus that eats keratin rich materials
human papilloma
virus (HPV) group of viruses that cause
various types of warts in
humans

62. Aging of the Integumentary System
Aging is due to:
intrinsic factors
(natural decline; genetic, maturation, stress)
extrinsic factors
(environmental factors, contracting disease, pollution)
lifestyle can accelerate aging
loss of head hair
graying/whitening of hair, decrease in sweating
excessive growth of hair, loss of fat
wrinkles; drying out of skin = decrease in oil

63. Concept Check Questions 19 - 21
19. Explain how the 3 categories of skin burns differ?
- 1st degree – superficial damage – reddening, swelling
-2nd degree – stratum germinativum damage - blisters
-3rd degree – dermis is damaged – nerve damage
20. According to the rules of nines, what % of my
body would be burned if the anterior part of 1 leg,
both sides of my right arm, and my head were burnt? 27%
21. How do the 3 categories of skin disorders differ?
-degenerative – progressive deterioration of skin
- genetic – inherited / mutations in DNA
- infectious - microorganisms

64. Concept Check Questions 22-24
22. Describe 2 types of degenerative skin conditions.
freckles & solar lentigene (age spots)  too much sun
dermatitis –> dry irritation of the skin
skin cancer –> abnormal, malignant growths of skin
23. Describe 2 types of genetic skin conditions.
Acne  infected sebaceous glands
Psoriasis  inflammation of skin
Port wine / vitiligo  birthmarks, reduced melanin
24. How do the 2 major categories of skin aging
differ?
Extrinsic environmentally triggered
Intrinsic  natural / genetic causes

65. continous high blood-sugar levels cause smaller blood
CSI Investigation
Name at least 3 symptoms your patient is suffering from.
elderly, obesity, high blood pressure & open sore
2. Based on these symptoms, what might your patient be suffering from?
decline of blood vessels associated with prolonged / untreated diabetes
3. Explain why/how the dermis became exposed in her sore?
continous high blood-sugar levels cause smaller blood
vessels in the skin to break down; skin can’t produce epidermis (and make S.Corneum layer that sheds with physical damage)

66. CSI Investigation
Why would such an “ugly” sore not cause any pain sensation?
As her personal trainer, why would you recommend
an exercise program for this patient? What would her
program entail?
Sore is deep in the skin; all nerves and receptors have been damaged.
Routine should include exercise that reduces weight and increases blood flow. Inflexible skin may cause restriction movements. Increase the amount of protein  build immune system and provide S.germinativum with amino acids required for normal rate of mitosis.

67. sores in elders are common  natural decrease in blood flow
CSI Investigation
exercise program  increase weight loss & increase blood flow  inflexibility of skin may cause movement restrictions??
sores in elders are common  natural decrease in blood flow
increase protein  provides stratum germinativum with amino acids to divide
avoid stress on body  reduces immune response and will slow healing