1. The Integumentary System
Chapter 1 Section 2

2. Overview
Integumentary System – consists of the skin and its accessory organs
hair, nails, and cutaneous glands
Most visible system and more attention paid to this organ system
Skin is the most vulnerable organ
exposed to radiation, trauma, infection, and injurious chemicals

3. Structure of the Skin 1 Square inch contains
20 blood vessels, hundreds of sweat glands, and more than a thousand nerve endings

4. Epidermis Outermost layer Composed of epithelial cells
Very Active layer and constantly being renewed
Cells at the bottom are always going through mitosis
New cells move up… as they move up they create fibrous protein called keratin
Once they reached the surface they are full of keratin and have died
Dead cells eventually shed off the surface

5. Melanocytes of the Epidermis
Melanocytes—produce melanin
Gives skin its color
The darker the skin the more melanin that is produced
Located at the deepest layer of the epidermis.
Protects against
UV damage.

6. Dermis Inner layer of skin made of connective tissue
Connected to the epidermis by a fiber protein called collagen
Contains all the structures
Sweat gland
Hair follicles
Sebaceous glands (oil glands)
Nerve endings
Blood vessels

7. Functions of the Skin Helps maintain homeostasis
Controls what enters and leaves the body
Prevents the loss of too much water
Melanin absorbs Ultraviolet light
Prevents the light from reaching and damaging the dermis
Regulated body temperatures

8. Hair and Nails Hair Nails Both Mammals are the only ones with hair
Protects from sun exposure and pathogens
Insulates the body
Nails
Protects fingers and toes
Aid in feeling things
Both
Made up of Keratin
Made up of dead and living cells

9. UV Core
UVA and UVB are improperly called “tanning rays” and “burning rays”
Both thought to initiate skin cancer
Sunscreens protect you from sunburn but unsure if provide protection against cancer
chemical in sunscreen damage DNA and generate harmful free radicals

10. Skin Cancer Skin cancer – induced by the ultraviolet rays of the sun
most often on the head and neck
most common in fair-skinned people and the elderly
one of the most common cancers
one of the easiest to treat
has one of the highest survival rates if detected and treated early
three types of skin cancer named for the epidermal cells in which they originate
basal cell carcinoma, squamous cell carcinoma, and malignant melanoma

11. Basal Cell Carcinoma - Most common type
(a) Basal cell carcinoma
- Most common type
- Least dangerous because it seldom metastasizes
- Forms from cells in stratum basale
- Lesion is small shiny bump with central depression and beaded edges

12. Squamous Cell Carcinoma
(b) Squamous cell carcinoma
- Arise from keratinocytes from stratum spinosum
- Lesions usually appear on scalp, ears, lower lip, or back of the hand
- Have raised, reddened, scaly appearance later forming a concave ulcer
- Chance of recovery good with early detection and surgical removal
- Tends to metastasize to lymph nodes and may become lethal

13. ABCD--asymmetry, border irregular, color mixed and diameter over 6 mm
Malignant Melanoma
(c) Malignant melanoma
Skin cancer that arises from melanocytes
Less than 5% of skin cancers, but most deadly form
Treated surgically if caught early
Metastasizes rapidly - unresponsive to chemotherapy - usually fatal
Greatest risk factor – familial history of malignant melanoma
High incidence in men, redheads, people who experience severe sunburn
in childhood
ABCD--asymmetry, border irregular, color mixed and diameter over 6 mm