Body membranes line body cavities and surfaces, and fall into two groups: epithelial and connective tissue membranes. Epithelial membranes include the cutaneous, mucous, and serous membranes which contain an epithelial sheet and underlying connective tissue. The skin is the cutaneous membrane and functions to protect the body, regulate temperature, and synthesize vitamin D. The skin has an outer epidermis and deeper dermis layer. Skin appendages like hair, nails, and glands aid homeostasis. Imbalances can include infections and allergies of the skin.

1. CHAPTER 4
SKIN AND BODY MEMBRANES

2. Body Membranes
 Body membranes cover surfaces, line
body cavities, and form protective
sheets around organs
 Fall into two major groups:
 1. epithelial membranes
include cutaneous, mucous, and serous
membranes
 2. connective tissue membranes
◦ Represented by synovial membranes

3. Body Membranes
 The functions of body membranes:
◦ 1. line or cover body surfaces
◦ 2. protect body surfaces
◦ 3. lubricate body surfaces

4. CLASSIFICATION OF
BODY MEMBRANES

5. Epithelial Membranes
 Epithelial
membranes
(covering and
lining
membranes)
include
cutaneous
membrane,
mucous
membranes, and
serous

6. Epithelial Membranes
 Calling these “epithelial” is inaccurate
 Do contain an epithelial sheet, but it is
always combined with an underlying
layer of connective tissue
 These are simple organs

7. Cutaneous Membranes
 Cutaneous Membrane: your skin
◦ Exposed to air
◦ Dry membrane
 The superficial epidermis
◦ keratinizing stratified squamous
epithelium
 The underlying dermis
◦ mostly dense connective tissue

8. Mucous Membranes
 Surface epithelium
◦ type depends on site
 Underlying loose
connective tissue
(lamina propia)
 Lines all body cavities
that open to the
exterior body surface
 Often adapted for
absorption and
secretion

9. Serous Membranes
 Surface simple squamous epithelium
 Underlying areolar connective tissue
 Lines open body cavities that are
closed to the exterior of the body
 Serous layers separated by serous
fluid

10. Serous Membranes
 Specific serous membranes
◦ Peritoneum
 Abdominal cavity
◦ Pleura
 Around the lungs
◦ Pericardium
 Around the heart

11. Connective Tissue
Membranes
 Synovial membrane
 Connective tissue only
 Lines fibrous capsules surrounding
joints
 Provide:
◦ Smooth surface
◦ Secrete lubricating fluid

12. Synovial Membrane

13. Connective Tissue
Membranes
 Synovial membrane
◦ Also line bursae and tendon sheaths
◦ Cushion organs moving against each
other during muscle activity

14. THE INTEGUMENTARY
SYSTEM (SKIN)

15. Integumentary System
 Skin (cutaneous membrane)
 Skin derivatives
◦ Sweat glands
◦ Oil glands
◦ Hairs
◦ Nails

16. Skin Functions
 Protects deeper tissues from:
◦ Mechanical damage
◦ Chemical damage
◦ Bacterial damage
◦ Thermal damage
◦ Ultraviolet radiation
◦ Desiccation

17. Skin Functions
 The uppermost layer of the skin is full
of keratin and is cornified, or
hardened, to help prevent water loss
from the body surface

18. Skin Functions
 Protects deeper tissues
 Aids in heat regulation
◦ Capillary network and sweat glands
 Aids in excretion of urea and uric acid
◦ Urea, salts, water
 Synthesizes Vitamin D
◦ Modified cholesterol molecules in the skin are
converted to Vitamin D by sunlight
 Cutaneous Sensory Receptors
◦ Tiny sensors detect touch, pressure,
temperature and pain

19. Skin Structure
 Epidermis – outer
layer
◦ Stratified
squamous
epithelium
◦ Often keratinized
 Dermis
◦ Dense connective
tissue

20. Skin Structure

21. Skin Structure
 Epidermis and dermis are firmly
connected
 A burn or friction may cause them to
separate
 Interstitial fluid accumulates, forms
blister

22. Skin Structure
 Deep to the dermis is the hypodermis
(subcutaneous tissue)
 Not part of the skin
 Anchors skin to underlying organs
 Composed mostly of adipose tissue

23. Skin Structure

24. EPIDERMIS

25. Epidermis
 Composed of up to five layers:
◦ Stratum basale
◦ Stratum spinosum
◦ Stratum granulosum
◦ Stratum lucidum
◦ Stratum corneum

26. Epidermis
 Most cells of the epidermis are
keratinocytes: keratin cells

27. Epidermis – Stratum basale
 Deepest cell layer in epidermis
 Lies closest to the dermis
 Receive the most nourishment,
through diffusion, from the dermis
 Cells are undergoing mitosis
 (also called the stratum germinativum)
 Pushed upward from this layer

28. Epidermis – Stratum basale

29. Epidermis – stratum spinsosum
and stratum granulosum
 Above the stratum
basale is the
stratum spinosum
and then the
stratum
granulosum
 Flatter, more
keratinized

30. Epidermis – Stratum lucidum
 Above the stratum granulosum is the
stratum lucidum
 Clear layer full of dead skin cells
 Not present in all skin regions
 Thick, hairless areas (palms, soles)
 High in keratin
 Far from blood supply

31. Epidermis – Stratum corneum
 Outermost layer
 Accounts for ¾ of epidermal thickness
 Shingle-like dead cells
 Completely filled with keratin
 Also called cornified or “horny cells”

32. Epidermis – stratum corneum
 The stratum corneum rubs and flakes
off slowly as dandruff
 The stratum corneum is replaced
quickly by rising cells from the stratum
basale
 We have an entirely new epidermis
every 25-45 days.

33. Epidermis - Melanin
 Melanin: pigment that ranges in color
from yellow to brown to black
 Melanin is produced by melanocytes
◦ Found mainly in the stratum basale
 Accumulates in membrane-bound
granules called melanosomes

34. Epidermis - Melanin
 The amount of
melanin in the
epidermis results
from genetics and
sunlight exposure
 Freckles and moles
are seen in areas
where melanin is
concentrated

35. DERMIS

36. Dermis
 Dermis – your hide
 Two layers:
 Papillary Layer (upper region)
 Reticular Layer (lower region)

37. Dermis – Papillary Layer
 Dermal Papillae
◦ Indent epidermis above
◦ Create fingerprints
 Capillary loops
◦ Nourish epidermis
 Pain and touch receptors
◦ Pain – free nerve endings
◦ Touch – Meissner’s corpuscles

38. Dermis – Reticular Layer
 Blood vessels
 Sweat and oil glands
 Deep pressure receptors – Pacinian
corpuscles
 Contain phagocytes that prevent
bacteria from reaching deeper tissues

39. Dermis
 Heavy in collagen and elastic fibers
 As age increases, these fibers
decrease as do fat cells and skin sags
 Abundantly supplied with blood
◦ Skin reds and warms with high body temp
 Rich nerve supply

40. SKIN COLOR

41. Skin Color
 Three pigments contribute to skin
color:
 1. the amount and kind of melanin
 2. the amount of carotene in the
stratum corneum and subcutaneous
tissue
 3. the amount of hemoglobin in the
dermal blood vessels

42. Skin Color
 People with a lot of melanin have
brown-toned skin
 People with less melanin have fair-
toned skin

43. Skin Color
 The hemoglobin in
the dermal blood
supply shows
through the
transparent cell
layers above
 This gives skin a
rosy glow

44. Skin Color
 Emotions also influence skin color,
and many alterations in skin color
signal disease:
 1. Redness (erythema) – reddened
skin
◦ Blushing, fever, hypertension,
inflammation, allergy

45. Skin Color
 2. Pallor (blanching)
◦ Emotional stress (fear, anger)
◦ Anemia, hypotension, impaired blood flow
 3. Jaundice (yellowing)
◦ Liver/Gallbladder disorders – excess of
bilirubin in the blood

46. Skin Color
 4. Bruises (black and blue coloring)
◦ Show where blood has escaped
circulation and has clotted in tissue
spaces
◦ Hematomas
◦ An unusual tendency to bruising may
signify a deficiency of vitamin C or
hemophilia

47. SKIN APPENDAGES

48. Skin appendages
 Skin appendages: skin-associated
structures that serve a particular
function
 Functions include sensation,
contractility, lubrication and heat loss

49. Skin Appendages
 Skin appendages
include cutaneous
glands, hair and hair
follicles, nails
 Arise from the
epidermis
 Play a role in
homeostasis

50. Cutaneous Glands
 Exocrine glands
◦ Release secretions to the skin surface via
ducts
 Two groups:
◦ Sebaceous glands
◦ Sweat glands
 Formed in the stratum basale and
push into the deeper layers of the
dermis

51. Sebaceous Glands
 Oil glands
 Found all over skin
except palms and soles
 Sebum: the product of
sebaceous glands
◦ Lubricate skin
◦ Kills bacteria
 Most with ducts empty
into hair follicles
 Increase production
during puberty

52. Sweat Glands
 Also called sudoriferous glands
 Widely distributed across the skin
 Two types:
 1. eccrine
◦ Open via duct to pore on skin
◦ Produce sweat
◦ Important in heat regulation
 2. apocrine
◦ Usually larger than eccrine glands
◦ Ducts empty into hair follicles
◦ Activated during pain and stress

53. Sweat Glands

54. Sweat and its Function
 Composition:
◦ Mostly water
◦ Some metabolic wastes (ammonia, urea,
etc.)
◦ Fatty acids and proteins (apocrine only)
 Function:
◦ Helps dissipate excess heat
◦ Excretes waste products
◦ Acidity decreases bacterial growth
 Odor is from associated bacteria

55. Hair and Hair Follicles
 Produced by hair
bulb
◦ Formed by well-
nourished stratum
basale cells in the
matrix (growth zone)
 Consists of hard,
keratinized
epithelial cells
 Melanocytes
provide pigment for
hair color

56. Hair and Hair Follicles

57. Hair Anatomy
 Central medulla
 Cortex surrounds
medulla
 Cuticle on outside
of cortex
◦ Most heavily
keratinized

58. Hair structures
 Hair follicle
◦ Dermal and epidermal sheath surround
hair root
 Arrector pili
◦ Smooth muscle
◦ Cause hair to stand up
◦ Goosebumps (piloerection)
 Sebaceous gland
◦ Lubricates hair
 Sweat gland

59. Hair function
 Warmth
◦ Limited in humans
 Protection
 Touch sense
 Non-verbal communication (eyebrows
and eyelashes)

60. Human Body Hair Types
 According to forensic scientists there
are six types of hair on the human
body:
 Head
 Eyebrow and eyelash
 Beard and moustache
 Body hair (Auxilairy)
 Pubic
 Armpit

61. Nails
 Scale-like modifications of the
epidermis
◦ Highly keratinized
 Stratum basale extends beneath the
nail bed
◦ Responsible for growth
 Lack of pigment makes them colorless

62. Nail Structures
 Free Edge
 Body
 Root of Nail
 Eponychium: proximal nail fold that
projects into the nail body

63. SKIN HOMEOSTATIC
IMBALANCES

64. Infections
 Athlete’s Foot
◦ Medically known as tinea pedis
◦ Caused by a fungal infection
◦ Thrives in warm, moist areas
◦ Contagious by contact

65. Infections
 Boils and Carbuncles
◦ Inflammation of hair follicles and
sebaceous glands
◦ Caused by bacterial infection

66. Infections
 Cold sores
◦ Caused by the Herpes Simplex Virus
◦ Can remain dormant for extended periods
of time

67. Infections
 Impetigo
◦ Caused by bacterial infection (staph)
◦ Highly contagious
◦ Common in elementary children

68. Allergies
 Contact dermatitis
◦ Exposure to substance causes an allergic
reaction
◦ Ex. poison ivy

69. Allergies
 Psoriasis
◦ Chronic, autoimmune condition
◦ Can be disfiguring
◦ Attacks are often triggered by trauma,
infection, stress or hormonal changes

70. BURNS

71. Burns
 Burn: tissue damage and cell death
caused by heat, electricity, UV
radiation (sunburns) or chemicals

72. Burns
 Immediate Associated Dangers:
 1. Dehydration
 2. Electrolyte Imbalance
 3. Circulatory Shock

73. Burns – Rule of Nines
 Way of determining the extent of
burns (how much of the body is
burned)
 Body is divided into 11 areas for quick
estimation
◦ Each area represents about 9% of the
body
◦ (last 1% is the area surrounding the
gentials)

74. Burns – Rule of Nines

75. Burns - Severity
 First-Degree
 Second – Degree
 Third-Degree

76. Burns - Severity

77. 1st degree burns
 Only the epidermis is damaged
(superficial)
 Skin is red and swollen
 No blistering
 Minimal pain
 Usually heals in a week or less
 Cool, cover loosely, over the counter
pain medications

78. 1st degree burns

79. 2nd degree burns
 Epidermis and upper dermis are
damaged (partial thickness)
 Skin is red
 Blisters that sometimes break
 Severe pain
 Takes up to a month to heal
 Cool, cover loosely, over the counter
pain meds
 Be cautious of infections

80. 2nd degree burns

81. 3rd degree burns
 Destroy entire skin layer (full thickness)
 Skin is gray-white or black; may appear
waxy of charred
 Minimal pain at first due to nerve
damage
 Partial or complete skin grafts, biomask,
amnion
 Possible system shock and cardiac or
respiratory arrest
 Extended healing time

82. 3rd degree burns

83. 3rd degree burn treatment

84. Critical Burns
 Burns are considered critical if:
 Over 25% of the body has 2nd degree
burns
 Over 10% of the body has 3rd degree
burns
 There are third degree burns of the
face, hands or feet

85. Critical Burns
 Facial burns
◦ Particularly dangerous
◦ Possibility of burns in
respiratory passage
◦ Can cause swelling and
suffocation
 Joints
◦ Scar tissue can limit mobility

86. SKIN CANCER

87. Skin Cancer
 Cancer – abnormal cell mass
 Two types
 Benign
◦ Does not spread (encapsulated)
 Malignant
◦ Metastasized (moves) to other parts of the
body
 Most common type of cancer

88. Skin Cancer Types
 Basal Cell Carcinoma
◦ Least malignant
◦ Most common type
◦ Arises from stratum basale

89. Skin Cancer Types
 Squamous Cell Carcinoma
◦ Arises from stratum spinosum
◦ Metastasizes to lymph nodes
◦ Early removal allows for a good chance of
a cure

90. Skin Cancer Types
 Malignant Melanoma
◦ Most deadly type of skin cancer
◦ Cancer of melanocytes
◦ Metastasizes rapidly to lymph and blood
vessels
◦ Detection uses ABCD rule

91. ABCD Rules

92. ABCD Rules
 A = Asymmetry
◦ Two sides of pigmented mole do not
match
 B = Border Irregularity
◦ Borders of mole are not smooth

93. ABCD Rules
 C = Color
◦ Different colors in pigmented area
 D = Diameter
◦ Spot is larger than 6mm in diameter

94. ABCD Rules