The Integumentary The Integumentary SystemSystem

Chapter 5

Standards and ObjectivesStandards and ObjectivesCLE 3251.2.1 Identify structures of the

integumentary system and show the relationship between these structures and their functions.

Identify the structures of the skin and explain their role in protecting the body and maintaining homeostasis.

CLE 3251.2.2 Investigate physiological mechanisms that allow the integumentary system to function.

Explain the physiological processes involved in healing the skin and disorders of the skin.

Construct a labeled model of the skin with descriptions of its functions.

Facts about the Facts about the Integumentary SystemIntegumentary System

1. Your skin is considered the largest organ in the human body.

2. Your skin is made up of three major layers - epidermis, dermis, and hypodermis (also called the subcutaneous tissue).

3. Your skin protects your inside organs while keeping infections out and prevents you from getting sick.

4. Your skin loses about 30,000 to 40,000 dead skin cells from the surface almost every minute and about 60-100 strands of hair per day, even though you do not see it happening.

5. Your skin sheds a layer of these dead cells every 24 hours and renews itself about every 28 days.

6. Your skin swells when it absorbs water. 7. Your skin contains a protein called keratin which is

also found in hair and nails8. Your skin is the thinnest on the eyelid. 9. Goose bumps are actually little pimples that help

retain a layer of warm air over our body.10.About 32 million bacteria call every inch of your skin

home.

CLE 3251.2.1 Identify structures of the integumentary system and show the relationship between these structures and their functions.

Identify the structures of the skin and explain their role in protecting the body and maintaining homeostasis.

Skin StructureSkin Structure

Epidermis: (epi – above) superficial epithelium

Dermis: underlying area of connective tissues

Hypodermis: AKA subcutaneous layer –loose connective tissue that separates the dermis from the deep fascia around other organs such as muscles or bones◦Fascia: connective tissue fibers, primarily

collagenous, that form sheets or bands beneath the skin to attach, stabilize, enclose, and separate muscles and other internal organs

◦Collagenous: made of strong, insoluble protein fibers that are common in connective tissues

Skin FunctionsSkin Functions

ProtectionExcretion of wastesTemperature regulationSynthesis of compounds

◦Melanin◦Keratin◦Calcitrol

Storage of chemical compounds◦Lipids

Sensations

The SkinThe Skin

Figure 5-1Components of the Integumentary System

https://www.youtube.com/watch?v=yKAzVC0WcmI

Changes in skin appearance Changes in skin appearance can help diagnose diseasescan help diagnose diseases Jaundice: the liver is unable to excrete bile, so

a yellowish pigment accumulates in body fluids, and in advanced stages, the skin and whites of the eyes turn yellow

Some tumors affecting the pituitary gland result in secretion of large amounts of melanocyte-stimulating hormone (MSH), causing a darkening of the skin, as it the individual has an extremely dark bronze tan.

Addison disease: the pituitary gland secretes large quantities of adrenocorticotropic hormone (ACTH), which is similar to MSH

Vitiligo: Melanocytes are lost due to immune defense malfunctions, where antibodies attack normal melanocytes, causing light spots on primarily dark-skinned individuals

Skin cancers and melanomas

CLE 3251.2.2 Investigate physiological mechanisms that allow the integumentary system to function.

Explain the physiological processes involved in healing the skin and disorders of the skin.

Construct a labeled model of the skin with descriptions of its functions.

Skin CancerSkin Cancer

Basal Cell Carcinoma◦ Most common, least malignant skin cancer◦ Usually occurs on face◦ Rx – surgical removal or radiation

Squamous Cell Carcinoma◦ Mostly scalp and lower lip◦ Grows rapidly and metastasizes to lymph nodes◦ Rx – surgical removal or radiation◦ Prognosis good with early diagnosis

Skin CancerSkin Cancer

Melanoma◦ Occurs in melanocytes◦ Metastasizes to other areas quickly◦ Appears as brown or black irregular patch that

occurs◦ Suddenly◦ A change in an existing wart or mole may indicate◦ Melanoma◦ Rx – surgical removal of melanoma and

surrounding area◦ and chemotherapy

Basal Cell CarcinomaBasal Cell Carcinoma

Human Anatomy, 3rd editionPrentice Hall, © 2001

Squamous Cell CarcinomaSquamous Cell Carcinoma

Human Anatomy, 3rd editionPrentice Hall, © 2001

MelanomaMelanoma

Human Anatomy, 3rd editionPrentice Hall, © 2001

Dermal Blood Supply and Dermal Blood Supply and InnervationInnervation

Cutaneous plexus: supplies the skin, hair follicles, sweat glands, and other structures in the dermis with blood, nutrients, and oxygen

Papillary plexus: provides blood to capillary loops that follow the contours of the epidermis-dermis boundary◦ Trauma to the skin often results in a

contusion (bruise),

Innervation : Nerve fibers in the skin control blood flow, adjust gland secretion rates, and monitor sensory receptors in the dermis and deeper layers of the epidermis

Dermal CirculationDermal Circulation

Section 5.6: Section 5.6: HypodermisHypodermisAKA Subcutaneous LayerConsists of areolar and adipose tissues and is

quite elastic Is a fatty layer that:

◦ provides extra insulation ◦ helps reduce heat loss◦ serves as an energy

reserve and a shock absorber for rough activities.

Section 5.10 – Section 5.10 – Regeneration of SkinRegeneration of Skin

Bleeding occurs when damage extends through the epidermis into the dermis.

Blood clot (scab) forms at the surface, temporarily restoring the integrity of the epidermis and restricting entry of additional microorganisms into the damaged area.

Over time, deeper portions of the clot dissolve, and the number of capillaries decline. Fibroblast activity leads to the appearance of collagen fibers and typical ground substance.

Formation of an inflexible, fibrous, noncellular scar tissue completes the repair process, but does not restore the tissue to its original condition.

Disorders of the SkinDisorders of the Skin

ACNE VULGARIS◦ Common and chronic disorder of

sebaceous glands◦ Sebum plugs pores; area fills with

leukocytes◦ Also – blackheads, cysts, pimples and

scarring

Disorders of the SkinDisorders of the Skin

ACNE VULGARIS

Disorders of the SkinDisorders of the Skin

ATHLETE’S FOOT◦ Contagious fungal infection◦ Usually contracted in public baths and

showers◦ Rx – antifungal agents

Disorders of the SkinDisorders of the Skin

DERMATITIS◦ Non-specific inflammation of skin◦ Can be rash – reaction to soap, plants,

etc.◦ Can be emotional – stress can cause

skin blotches

Disorders of the SkinDisorders of the Skin

ECZEMA◦ Acute or chronic, inflammatory skin

disease◦ Dry, red, itchy and scaly◦ Rx – remove or avoid causative agent,

hydrocortisone to help alleviate the symptoms

Disorders of the SkinDisorders of the Skin

WARTS (VERRUCAE)◦ Caused by virus◦ Some disappear spontaneously,

others removed withliquid nitrogen, chemicals or laser

Disorders of the SkinDisorders of the Skin

IMPETIGO◦ Acute, inflammatory and contagious◦ Seen in babies and young children◦ Caused by staphylococcus or streptococcus◦ Characterized by the appearance of vesicles

which

rupture and develop distinct yellow crusts

Disorders of the SkinDisorders of the Skin

PSORIASIS◦ Chronic inflammatory skin disease

characterized by dry reddish patches which are covered with silvery-white scales

◦ Affects the skin surface over elbows, knees, shins, scalp and lower back

◦ Cause – unknown◦ Onsets triggered by stress,

trauma or infection

Disorders of the SkinDisorders of the SkinRINGWORM

◦ Highly contagious fungal infection◦ Can be contracted from infected animals◦ Raised, itchy circular patches with crusts◦ Skin, scalp or underneath nails◦ Rx – griseofulvin (drug)

Disorders of the SkinDisorders of the SkinBOILS (CARBUNCLES)

◦ Painful, bacterial infection of hair follicle or sebaceous glands

◦ Caused by staphylococcus organism◦ Rx – antibiotics, excision and drainage

of affected area

Disorders of the SkinDisorders of the SkinSHINGLES (HERPES ZOSTER)

◦ Viral infection of nerve endings◦ Can be caused by dormant chicken

pox virus◦ Chest or abdomen, accompanied by

severe pain◦ Rx – medication for pain and itching

Disorders of the SkinDisorders of the Skin

HERPES SIMPLEX I◦ Viral and contagious

Spread by kissing, eating/drinking after infected person, sharing lipstick, etc.

◦ Symptom includes Fever blister or cold sore

Disorders of the SkinDisorders of the Skin

SCABIES◦ Communicable, severe itching◦ Contracted from infected living or

nonliving things◦ Mite burrows in skin, lays eggs, eggs

hatch

BurnsBurns• A simple, moderately severe sunburn

damages the blood vessels extensively. How extensively? Studies have shown that it can take four to fifteen months for them to return to their normal condition. Consider that the next time you’re feeling too lazy to apply sunscreen before heading outside.

Caused by radiation, sun, boiling water, chemicals, fire or electricity

RULE OF NINES – Measures percent of body burned.

Body divided into 11 areas; each is 9% of body surface.

FIRST DEGREE BURNS◦ Superficial◦ Skin red and dry◦ Involves only epidermis◦ Rx – cold water◦ Healing within one week

SECOND DEGREE BURNS◦ Epidermis and dermis◦ Pain, swelling, redness and blistering◦ Skin may be exposed to infection◦ Rx – pain medication, dry sterile dressing◦ Healing within 2 weeks

THIRD DEGREE BURNS◦ Epidermis, dermis and subcutaneous layers◦ Symptoms – loss of skin, blackened skin◦ May be life threatening