Anatomy

• Protection
• Body Temp regulation
• Blood Reservoir (Kept at surface of skin)
• Excretion
• Sensation
• Vitamin D synthesis

• 1. Constrict blood vessels (less blood to surface)
• 2. Contraction of dermal muscles (->heat; goosebumps)

• 1. Dilate blood vessels (More blood to surface)
• 2. Sweat (evaporative heaat loss)

Epidermis + Dermis

Hypodermis

• Epidermis
• Dermis
• Hypodermis

• 1. Avascular
• 2. 90% are keratinocytes
• a) Filled w keratin
• b) Waxy waterproofing
• 3. Deepest layer divides, pushing older cells up (away from blood)
• 4. 5 layers in epidermis ( 4 in thin skin)
• 5.Forms hair, nails, and glands
• 6. Melanocytes found here (skin color) PIGMENT PRODUCING CELLS

• waxy, watery substance protecting skin.
• Dead skin

• Hair
• Nails

• Carotene- fruits and veggies/
• a)Yellow orange color

• Blood-
• a) dilation constriction
• b) de-oxygentated (cyanosis)

• Melanocytes
• a)Same # in all racces

• 1. Superficial layer
• 2. Areolar (loose) CT
• 3. Form Dermal Papilae to fingerprint.
• 4. Capillary loops/ tactile receptors.

• Papillary
• Reticular

• 1) Dense Irregular CT
• 2) Majority of dermis
• 3) Location of most organs

• 1. Adipose connective tissue
• 2. Connects skin to organs
• 3. Varying amount of fat.
• 4. Subcutaneous layer = superficial fascia

• 1. Glands
• 2. Hair
• 3. Smooth Muscle
• 4. Sensory Receptors

• Oil Glands
• Sweat Glands

• a) Sebaceous Glands
• b) activated by hormones
• c) waterproofing; acne

Holocrine Mode of Secretion used!

• a) Eccrine Sweat Gland
• - Watery Sweat
• - All over body (dense in hand/feet).
• - Activated by temp. & anxiety.

• b) Apocrine Sweat Gland
• - Found in armpit/ genitals
• - Thich secretion
• - Smelly

Merocrine Mode of Secretion used!

• Sweat Glands- Eccrine / apocrine
• a) Most common
• b) Secretions in vesicles -> fuse to cell membrane ->deposits prouct outside cell.
• c) Discharge secretion through EXOCYTOSIS
• d) Cell Remains intact

• Mammary Glands
• a) Secretions in vesicles near apical region of cell.
• b) Discharge by PINCHING OFF APICAL SURFACE OF CELL.
• c) Basal cell region remains intact.

• Sebaceous Glands
• a) Secretions in vesicles fill cell cytoplasm.
• b) Discharge secretion through CELL LYSIS
• c) Cell dies (only found in stratified tissue)

• 1. Composed of epithelial cells from epidermis.
• 2. Only living cells at ''bulb'' of hair.
• 3. Hair mainly dead cells.
• 4. Smooth muscle attached to hair follicle.

• 1. Composed of smooth muscle
• 2. Activated by cold and nerves.
• 3.

• a) Pale skin
• b) Reduced tolerance for sun exposure.

Reduction in sebaceous and sweat gland activity.

• a) Slow repairs
• b) Decreased vitamin D production
• c) Reduced number of Langerhans cells

Tendency to overheat

Sagging and wrinkling due to fiber loss

• a) Slow hhealing
• b) Reduced ability to lose heat

a) Due to reduction and sex hormone levels

Thinner, sparce hairs.

Melanocytes slowly destroyed by white blood cells..

WBC Mistake them as foreign.

De-pigmentation occurs in patches.

• 1) Most Common
• 2) Arise from deepest cells of epidermis.
• 3) Slow growing.
• 4) Rarely metastasizes.

• 1) 2nd most common
• 2) Arise from superficial cells of epidermis.
• flattening = squamous
• 3) Faster growing
• 4) Some metastasizes

• 1) Most Dangerous
• 2) Arise from melanocytes
• 3) Survival 90% (if not metastasized)
• 4) Survival 14% (if widespread metastasis)