Chapter 6: The Integumentary System
•skin is the largest organ
Two layers of the skin:
Epidermis: surface layer
Dermis: deep layer
-hypodermis
A. Epidermis:
- stratified squamous
- avascular
- 4-5 layers deep
1. stratum germinativum (basal layer)
-firmly attached to dermis
-consists mostly of
-melanocytes
2. stratum spinosum (spiney layer)
-melanin granules present here
-Langerhans cells
3. stratum granulosum (granular layer)
-thin zone
4. stratum lucidum (clear layer)
-consists of a few rows of flattened dead keratinocytes
-present only
5. stratum corneum (horny layer)
-outermost layer; protect against abrasion and penetration
- thickest layer (even thicker in areas of increased friction)
-accounts for 3/4 of the epidermal thickness
B. Dermis

cells found here are those typically found in connective tissue

gel-like matrix heavily embedded w/ collagen, elastin, & reticular fibers

dermis is your "hide"

richly supplied with

epidermal ridges on ventral surface of hands & feet along with dermal papillae
arranged in patterns create
-cleavage or tension lines in the skin
-stretch marks
-blister:

Box 6-1 Thick and Thin skin
Subcutaneous Layer (hypodermis)
Sebaceous (Oil) glands

Sebum

Sebaceous follicles
Sweat (Sudoriferous) Glands:
- distributed all over the skin

Eccrine

Apocrine

Ceruminous
Hair:

only hairless skin is found

primary function is

hair grows as result of mitotic activity of epidermal cells at the bottom of the hair follicle


hair growth is cyclic
follicles extend from dermis --> epidermis

root

shaft:

hair color determined by melanin

arrector pili: smooth muscle
Nails:

Thick, heavy keratinized cells

Regions

cuticle:

lunula:
Functions of the skin:
1. Protection
- chemical
- physical
- biological
2. Body Temperature Regulation
vasodilate
vasoconstrict
3. Cutaneous sensations
4. Metabolic, Storage & Secretion functions
Insensible vs. sensible perspiration
Observance of the Skin
Color

Pigment
o Melanin and Carotene
o Albinism

Quantity of blood circulating near the surface

Composition of circulating blood

Discoloration
o Pallor is
o Flushing is
o Cyanosis is
o Jaundice is

Various disease states will cause this discoloration
Lesions – changes in skin structure
Surface Lesions are often called rashes, unless raised

These lesions may be local or general

Accompanied by erythema

Macule –

Papule –

Vesicle –

Pustule –
Deep lesions may develop from a surface lesion or from trauma

Exscoriation -

Laceration –

Ulcer –

Fissure –
Burns and Grafts

1st degree – Partial thickness (superficial)

2nd degree - Partial thickness (deep)

3rd degree – Full-thickness

Rule of nines –

Sunburn – (Box 6-3)
Tissue Response to Injury and Tissue Repair:
First phase - Inflammation: short term (acute) inflammation has 4 symptoms:
1.
2.
3.
4.
Initial insult causes release of chemicals from White Blood Cells

these chemicals cause
1. regeneration:
2. fibrosis: scar tissue

Wound healing is affected by:
o Nutrition
o Blood Supply
o Infection
o Age
Aging and the Integument
1.
2.
3.
4.
5.
6.
7.
Skin Disorders
Dermatology is the study of
Dermatitis

Contact dermatitis

Eczema

Diaper Rash

Urticaria

Seborrheic dermatitis
Psoriasis
Acne and Skin Infections
Acne – most common form is acne vulgaris

Impetigo
Viral Infections

Fever blisters

Chicken pox

Shingles

Warts

Ulcers
Fungi

Athlete’s foot

Candidiasis
Alopecia (baldness)
Alopecia areata (immune disorder) – may affect either gender
Treatment of Skin Disorders
Transdermal administration
Surgical removal, destroying cells (cryotherapy or laser/electrosurgery), or skin grafts (large
areas)
Chemotherapy (anti-inflammatory drugs)
Tumors
o Melanomas
A
B
C
D
Pathologists specialize in the study of disease process

Use of biopsies
DysplasiaMetaplasiaAnaplasiaOncologists specialize in the identification and treatment of cancers

Classify cancers according to appearance and site of origin
o Carcinoma, Sarcoma, Leukemia, Gliomas

Goal of treatment is to achieve

Treatment includes
1. Surgical removal or destruction of individual tumors
2. Killing metastatic cells throughout the body