Post on 02-Jan-2016
Skin and Body Membranes I and II Types of Body Membranes
Cutaneous, mucus, serous
The Integumentary System (Skin)
Skin Structure (epidermis, dermis)
Skin Color (pigments and body conditions)
Appendages of the Skin (oil & sweat, hair, nails)
Diseases/Injuries to Skin (infections, burns, cancer)
Changes in the Skin Over a Lifetime
Mucous Membranes: Prone to Dessication
Also:
Urethra
Vaginal tract
Digestive tract, anus
Nostrils
Epithelium of the esophagus
Found lining the inside edges of organs or tracts
that empty into the exterior of the body
Serous Membranes- Thin linings of organs and body wall
• Parietal serosae line internal body walls
• Visceral serosae cover internal organs
Connective Tissue Membrane Synovial membrane
Cutaneous Membrane
Functions of the Integumentary System1. Protection (chemical, physical, biological)
2. Body temperature regulation ( perspiration, dermal vessels)
3. Cutaneous sensations (temperature, touch, and pain)
4. Metabolic functions (synthesis of vitamin D precursor and collagenase; chemical conversion of carcinogens and some hormones
5. Blood reservoir—up to 5% of body’s blood volume
6. Excretion—nitrogenous wastes and salt in sweat
Skin Structure
Epidermis Keratinized stratified squamous epithelium
Cells of epidermis
Keratinocytes—produce fibrous protein keratin
Melanocytes
10–25% of cells in lower epidermis
Produce brown pigment melanin
Epidermal dendritic (Langerhans) cells—macrophages that help activate immune system
Tactile (Merkel) cells—touch receptors
Detail of Epidermal Skin Structure
Melanocyte
Melanin granule
Tactile (Merkel) cell
Sensorynerve ending Epidermal
dendritic cell
Dermis
KeratinocytesStratum corneum20-30 layers of dead keratinized cells; glycolipids in interstitial spaces.
Stratum granulosumThree to five layers of flattened cells,organelles deteriorating; cytoplasm full of released lipids
Stratum spinosumSeveral layers of keratinocytes unified by desmosomes.
Stratum basaleone row of actively mitotic stem cells; melanocytes and epidermaldendritic cells.
Desmosomes
Mnemonic: Basically, the spinning by granny is loose and corny.
Stratum lucidumVery thin layer of dead, translucent keratinocytes; only palms, soles of feet
Dermis Strong, flexible connective tissue
Cells include fibroblasts, macrophages, and occasionally mast cells and white blood cells
Two layers:
Papillary
Reticular
Skin Structure
Figure 5.1
Epidermis
Hair shaft
Dermis Reticularlayer
Papillarylayer
Hypodermis(superficial fascia)
Dermal papillae
Pore
Subpapillaryvascular plexus
Appendagesof skin
• Eccrine sweat gland• Arrector pili muscle• Sebaceous (oil) gland• Hair follicle• Hair rootNervous structures
• Sensory nerve fiber• Pacinian corpuscle• Hair follicle receptor (root hair plexus)
Cutaneous vascularplexus
Adipose tissue
Layers of the Dermis: Papillary Layer Papillary layer
Areolar connective tissue with collagen and elastic fibers and blood vessels
Dermal papillae contain:
Capillary loops
Meissner’s corpuscles (touch se0nsing)
Free nerve endings .1
Layers of the Dermis: Reticular Layer Reticular layer
~80% of the thickness of dermis
Collagen fibers provide strength and resiliency
Elastic fibers provide stretch-recoil properties
Pacinian corpuscles (pressure and vibration sensing)
Normal Skin Color Determinants Chemicals in the Skin
Melanin
Carotene
Hemoglobin
Body Conditions
Erythmea (from embarrassment, fever, tension)
Pallor/Blanching (stress, etc.)
Jaundice from liver disease
Bruises from hematomas
Cyanosis from low blood oxygen
Appendages of the Skin Derivatives of the epidermis
Sweat glands
Oil glands
Hairs and hair follicles
Nails
Cutaneous Glands: Sebaceous & SweatEccrine (Merocrine)
Sweat Glands
water
salts
vitamin C
metabolic wastes
ammonia
urea
uric acid
lactic acid
Sebaceous glands
(holocrine)
Sebum
- fragmented cells
- fatty acids
- Low pH
(antibacterial)
Apocrine sweat glands confined to axillary and genital areas
- Sebum: sweat + fatty substances and proteins
-Ducts connect to hair follicles
-Functional from puberty onward (as sexual scent glands?)
Specialized apocrine include
- Ceruminous glands
- Mammary glands
Appendages of the Skin: Hair Hair and Hair Follicles
Appendages of the Skin: Hair
Hair follicle
and arrector
pili muscle
Appendages of the Skin: Nails Finger Nail and Nail Bed
(Eponychium)
Abnormal or Injured Skin Conditions Infections and Allergies of the Skin
Athletes foot (caused by tinea pedia fungus)
Boils and carbuncles (caused by inflammation and/or bacterial infection of oil glands or follicles
Cold sores (caused by viruses like Herpes)
Contact dermatitis (caused by allergic reaction)
Impetigo (caused by staph bacteria)
Psoriasis (scaly skin caused by overproduction and of cells)
Burns Heat, electricity, radiation, certain chemicals
Burn
(tissue damage, denatured protein, cell death)
Immediate threat:
Dehydration and electrolyte imbalance, leading to renal shutdown and circulatory shock
Abnormal or Injured Skin ConditionsThe Rule of Nines for Estimating Burned Surface Area
Burns are critical if:
• >25% has second-degree
• >10% has third-degree
• Any of face, hands, or feet with third-degree
Abnormal or Injured Skin Conditions
Burns
First-degree burns
Only epidermis is damaged
Skin is red and swollen
Second degree burns
Epidermis and upper dermis are damaged
Skin is red with blisters
Third-degree burns
Destroys entire skin layer
Burn is gray-white or black
Partial
thickness burns
Full
thickness
burn
Abnormal or Injured Skin ConditionsCancers (Cause: UV, freq. irritation)
Basal cell carcinoma
Least dangerous
Most common type
Arises from stratum basale
Squamous cell carcinoma
Arises from stratum spinosum
Metastasizes to lymph nodes
Early removal allows a good chance of cure
Abnormal Conditions: Skin Cancer Types
Malignant melanoma
Most deadly of skin cancers
Cancer of melanocytes
Metastasizes rapidly to lymph and blood vessels
Detection uses ABCD rule
ABCD Rule in Detecting Melanoma
Skin Tags (Acrochordons/ Cutaneous Papillomas)
Skin tags are benign growths that are not cancerous
Skin Changes Over a Lifetime
lanugo milia acne
dermatitis
vernix caseosa aging skin