Skin and Body Membranes

1
CHAPTER 4

• Skin and Body Membranes

2
Function of Body Membranes

• Line or cover body surfaces
• Protect body surfaces
• Lubricate body surfaces

3
Classification of Body Membranes

• Epithelial Membranes are simple organs
• Cutaneous membranes
• Mucous membrane
• Serous membrane
• Connective Tissue Membranes

4
Cutaneous Membrane

• Cutaneous Membrane skin
• A dry membrane because it is exposed to air
• Outermost protective boundary
• Superficial Epidermis
• Keratinized stratified squamous epithelium
• Underlying Dermis
• Mostly dense connective tissue

5
Mucous Membranes

• Wet or moist membranes
• Surface Epithelium
• Type of epithelium depends on its location
• Has a layer of underlying loose connective tissue
  called the lamina propria
• Lines all body cavities that open to the exterior
  body surface
• Respiratory, Digestive, and Reproductive organs
• Adapted for absorption or secretion

6
Serous Membranes

• Serous Membranes Serosa
• Surface simple squamous epithelium with
  underlying areolar connective tissue
• Lines open body cavities that are closed to the
  exterior of the body
• Serous membranes occur in pairs
• Parietal lines the cavity wall
• Visceral covers the outside of the organ
  contained in the cavity

7
Serous Membranes

• Serous layers are separated by serous fluid which
  helps to reduce friction between organs.
• Specific Serous Membranes
• Peritoneum covers the abdominal cavity
• Pleura surrounds the lungs
• Pericardium surrounds the heart

8
Connective Tissue Membrane

• Synovial Membrane
• Made of connective tissue only
• Lines fibrous capsules surrounding joints

9
Synovial Membrane
10
Integumentary System

• Components include
• Skin cutaneous membrane
• Sweat glands
• Oil glands
• Hairs
• Nails

11
Integumentary System

• Protects deeper tissues from
• Mechanical Damage
• Chemical Damage
• Bacterial Damage
• Thermal Damage
• UV Radiation
• Drying Out

12
Integumentary System

• The skin aids in
• Heat Regulation
• Excretion of urea and uric acid
• Synthesizing vitamin D

13
Skin Structure

• Has 3 layers
• Epidermis outermost layer
• Stratified squamous epithelium
• Often keratinized (hardened by keratin)
• Dermis middle layer
• Dense connective tissue
• Firmly connected to epidermis
• Hypodermis aka subcutaneous tissue deep to
  the dermis
• Not part of the skin
• Anchors skin to underlying organs
• Composed mostly of adipose tissue

14
Skin Structure
15
Layers of the Epidermis

• Stratum Basale
• Layer lying next to the dermis and is undergoing
  mitosis
• Stratum Spinosum
• Stratum Granulosum
• Stratum Lucidum
• Occurs only in thick skin
• Stratum Corneum
• 20 to 30 cell layers thick
• Shingle-like dead cells
• Have a totally new epidermis every 25-45 days

16
Melanin

• Pigment produced by melanocytes
• Color is yellow to brown to black
• Found mostly in the stratum basale
• Amount produced depends upon genetics and the
  exposure to sunlight

17
Layers of the Dermis

• Papillary Layer
• Have projections called dermal papillae
• Contain pain receptors (Meissners corpuscles)
  and capillary loops
• Reticular Layer
• Deepest skin layer
• Contains blood vessels, glands, and pressure
  receptors (Pacinian corpuscles)

18
Normal Skin Color Determinants

• Melanin yellow, brown, or black pigments
• Carotene orange-yellow pigment from some
  vegetables
• Hemoglobin red coloring from blood cells in the
  dermis capillaries oxygen content determines the
  extent of red coloring

19
Accessory Organs of the Skin

• Sebaceous Glands produce oil
• Acts as a lubricant for skin and kills bacteria
• Most have ducts that empty into hair follicles
• Glands are activated at puberty

20
Accessory Organs of the Skin

• Sweat Glands widely distributed in skin
• 2 types
• Eccrine open via duct to pore on skin surface
• Apocrine ducts empty into hair follicles
• Composition of sweat
• Mostly water, some metabolic waste
• Only in apocrine glands fatty acids proteins
• Function
• Helps get rid of excessive heat
• Excretes waste products
• Its acidic nature inhibits bacteria growth
• Odor is from associated bacteria

21
Accessory Organs of the Skin

• Hair produced by hair follicle
• Consists of hard keratinized epithelial cells
• Melanocytes provide pigment for hair color

22
Hair

• Has a central medulla, a cortex that surrounds
  it, and a heavily keratinized cuticle on the
  outside of the cortex

23
Hair

• Arrector Pili muscle that contracts when we are
  cool to give the appearance of goose bumps
  because it is attached to the hair follicle

24
Accessory Organs of the Skin

• Nails scale-like modifications of the epidermis
  that are heavily keratinized
• Have a lack of pigment that makes them colorless
• Stratum basale extends beneath the nail bed so
  that the nail grows

25
Nails
26
Skin Homeostatic Imbalances

• Infections (page 107)
• Athletes Foot caused by fungal infection
• Boils Carbuncles caused by bacterial
  infection
• Cold Sores caused by a virus
• Contact Dermatitis exposures cause an allergic
  reaction
• Impetigo caused by bacterial infection
• Psoriasis cause is unknown but is triggered by
  trauma, infection, and stress

27
Burns (pages 108 109)

• Tissue damage and cell death caused by heat,
  electricity, UV radiation, or chemicals
• Dangers of burns include dehydration, electrolyte
  imbalance, and circulatory shock
• Rule of Nines is a way to determine the extent
  of burns
• Body is divided into 11 areas for quick
  estimation and each area represents about 9

28
Severity of Burns

• 1st Degree Burns only epidermis is damaged
• Skin is red and swollen
• 2nd Degree Burns epidermis and upper dermis are
  damaged
• Skin is red with blisters
• 3rd Degree Burns destroys entire skin layer
• Burn is gray-white or black

29
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 3rd degree burns of the face, hands, or
  feet

30
Skin Cancer

• Skin Cancer most common type of cancer
  abnormal cell mass 2 types
• Benign does not spread
• Malignant metastasized (moves) to other parts
  of the body

31
Basal Cell Carcinoma

• Least malignant
• Most common type arises from stratum basale

32
Squamous Cell Carcinoma

• Early removal allows a good chance of cure
• Arises from stratum spinosum
• Metastasizes to lymph nodes

33
Malignant Melanoma

• Most deadly of skin cancers
• Cancer of melanocytes
• Metastasizes rapidly to lymph and blood vessels

34
Detection of Skin Cancer

• Uses ABCD rule
• A Asymmetry
• 2 sides of pigmented mole do not match
• B Border irregularity
• Borders of mole are not smooth
• C Color
• Different colors in pigmented area
• D Diameter
• Spot is larger than 6mm in diameter