Integumentary system

Connective tissue, Epithelial

2 major categories of membranes in the body

Synovial membrane consists of...

1. areolar connective tissue

2. no epithelial cells

function of synovial membrane

1. line fibrous capsules surrounding joints

2. lining of bursae and tendon sheaths

3. Provide smooth surface in joint

4. Secrete lubricating fluid

Epithelial membrane

Covering or lining membranes

Epithelial membranes include...

Cutaneous, mucous, serous

Epithelial membranes consist of...

1. epithelial sheet

2. Always combined with underlying connective tissue

Cutaneous membrane

1. AKA skin

2. Two distinct layers... Epidermis + Dermis

Epidermis

1. superficial layer of cutaneous

2. Comprised of keratinizing stratified squamous epithelium

3. Avascular

4. Contains most keratinocytes

Dermis

1. Mostly fibrous connective tissue

2. Thickness varies depending on location

Mucous membrane

1. Epithelium resting on layer of loose connective tissue

2.Line hollow organs and body cavities

3. Exposed to the outside world

4. Simple squamous OR simple columnar epithelial cells

5. Adapted for secretion or absorption

Serous membrane

1. Layer of simple squamous epithelium resting on thin layer of areolar connective tissue

2. Closed from the outside world

3. Occur in pairs

3 serous membrane linings...

1. Peritoneum = abdominal cavity

2. Pleura = lungs

3. Pericardium = heart

2 serous membrane layers

1. Parietal= lining for cavity

2. Visceral= lining for outside of organs

Serous fluid

1. separates parietal and visceral layers

2. Secreted by parietal and visceral layers

3. Allows for frictionless surface

Integumentary system functions

1. Protection

2. Temperature regulation

3. Excretion and absorption

4. General sensory organ

5. Synthesis of vitamin D

Integumentary system provides protection from

1. Mechanical

2. Chemical

3. Bacterial

4. UV

5. Thermal

6. Water level maintenance

Integumentary system temperature regulation

1. Capillaries

2. Sweat glands

Structure of skin

1. Epidermis

2. Dermis

3. Subcutaneous tissue (NOT part of skin)

Subcutaneous tissue

1. Deep to dermis

2. AKA Hypodermis

3. Essentially adipose tissue

4. serves as connecting point for skin and organs

5. Shock absorber and insulator

keratin

Fibrous protein making epidermis tough (protective layer)

Layers of Epidermis

1. Stratum Corneum

2. Stratum Lucidum

3. Stratum Granulosum

4. Stratum Spinosum

5. Stratum Basale

Keratinocytes

Cells producing keratin

Stratum Corneum

1. Superficial layer of epidermis

2. 20 to 30 cells thick (75% of epidermis thickness)

3. All cells are dead and keratinized

4. Sloughed off every 25 to 45 days

Stratum Lucidum

1. Areas of body with thicker layers of skin

2. Hairless (palms/ soles of feet)

Stratum Granulosum/ Spinosum

1. two layers above basale

2. Cells pushed upward become flatter and more keratinized

3. Cells leaving this layer die forming Lucidum

Stratum Basale

1. Deepest layer of epidermis

2. Connected to dermis

3. Most nourished layer

4. Pushes new cells upward

5. Area of most cell division

Cells in Epidermis

1. Melanocytes

2. Epidermal dendritic

3. Merkel

Melanocytes

Produce melanin (dictate skin color)

Epidermal dendritic cells

Alert immune system to bacterial or viral threat

Merkel cells

1. Associated with sensory nerve endings

2. Serve as touch receptors

Layers of dermis

1. Papillary

2. Reticular

Papillary layer

1. Superficial layer of dermis

2. Dermal papillae

Dermal papillae

1. Indent epidermis

2. Allow for increase in nutrition for epidermis

3. House free nerve endings and touch receptors

Reticular layer

1. Deep layer of dermis

2. Irregularly arranged connective tissue

3. Well vascularized

What does the reticular layer house

1. Blood vessels

2. Sweat and oil glands

3. Deep pressure receptors (Lamellar corpuscles)

4. Phagocytes

5. Collagen and elastic fibers

Sensory receptors

1. Located in cutaneous

2. Respond to stimuli

3. Produce general senses (touch, temperature, pain, vibration, pressure)

Cyanosis

1. Blue skin

2. poor oxygenation of blood

Erythema

1. Redness of skin

2. Fever or inflammation

Pallor

1. Whiteness of skin

2. Low BP, poor perfusion, anemia

Jaundice

1. Yellowness of skin

2. Liver disorder

Hematoma

1. Black and blue skin

2. Bruising, blood clotting

Cutaneous glands

1. Sebaceous

2. Sudoriferous

Sebaceous glands

1. Oil glands

2. Found in entire body (EXCEPT palms and soles of feet)

3. Ducts empty into hair follicle

4. Produce sebum

Sebum

1. Oily substance containing fragmented cells

2. Keeps skin soft and moist

3. Keeps hair from being brittle

4. Contains bacteria killing substance

Sudoriferous glands

1. Sweat glands

2. Found in entire body

3. Two main types... Eccrine and Apocrine

Eccrine glands

1. Water, salts, vitamin C, metabolic waste

2. slightly acidic

3. Important to thermoregulation

Apocrine glands

1. contain fatty acids and proteins

2. Function unknown

3. Activated by pain, stress, sexual activity

4. Bad odor when combined with bacteria on skin

Common skin ailments

1. bacterial infections

2. viral infections

3. fungal infections

Burn causes

1. Heat

2. electricity

3. UV

4. Chemicals

Burn impact

1. Denature proteins

2. Cell death (in affected area)

3. Prone to infection

4. Loss of fluid

First degree burn

1. ONLY epidermis is damaged

2. skin becomes red and swollen

second degree burn

1. Damage to epidermis and upper layers of dermis

2. skin blisters

3. Regneration is possible

third degree burn

1. Damage affects ALL layers of skin

2. AKA full thickness burns

3. skin is white or black

4. Non-painful (no nerve endings)

5. Regeneration not possible

Cold sores

1. Fluid filled blister

2. Caused by herpes simplex virus

3. Localizes on cutaneous nerve

4. Becomes active secondary to emotions, fever, UV

Impetigo

1. Pink water-filled, raised lesion

2. Common around nose and mouth

3. Yellow crust that ruptures

4. Caused by staph infection

5. Common among school age children

Psoriasis

1. Chronic

2. Over production of skin cells

3. red lesions covered by dry silvery scales

4. Auto-immune disorder

5. Caused by trauma, infection, hormonal changes, stress

Skin cancer

1. Most common cancer

2. Most are benign

3. Caused by UV, exposure to chemicals, physical trauma

Basal cell carcinoma

1. Least malignant

2. Most common skin cancer

3. Stratum basale altered; unable to form keratin

4. Infiltrate dermis and subcutaneous tissue

5. Slow growth

6. Curative via surgery

Squamous cell carcinoma

1. Arises from stratum spinosum

2. Scaley, red papule forming ulcer with firm border

3. Common on scalp, ear, dorsal of hands, lower lip

4. Rapid growth

5. metastasizes to local lymph nodes

6. Chances of recovery = high if caught early

Malignant melanoma

1. cancer of melanocytes

2. 5% of skin cancer

3. Often fatal

4. Develops from pre-existing mole

5. Spreading brown or black patch of skin

6. Metastasizes to lymph nodes

7. Early detection important

8. Sunbathing and tanning beds produce risk

ABCD and sometimes E of melanoma

Asymmetric= sides don't match

Borders= irregularity

Color= Inconsistent

Diameter= 6mm+

Evolution= Changes