The Integumentary System

Chapter 6

What is the integumentary system?

• skin

• hair

• nails

• glands

• blood vessels

• sensory receptors

What is your skin made of?

• 3 layers

• epidermis (outside)

• dermis (middle)

• subcutaneous layer (inside)

What is the epidermis?• outer layer of the skin, composed of 5 strata

(layers)

• stratum corneum - contains cells hardened with keratin for protection

• stratum lucidum - additional layer found only on palms of hands and soles of feet, provides additional thickness

• stratum granulosum - contains cells that secrete keratin

• stratum spinosum - contains cells that produce keratin

• stratum basale (basal cell layer) - contains epidermal stem cells that divide and migrate to the upper layers

What is in the dermis?

• middle layer of the skin

• made of loose connective tissue

• contains many small structures that help the skin function

• What structures are in the dermis?

• hair follicles - helps with sensing touch, insulation and protection

• arrector pili muscles - make the hairs stand up

• sweat glands - 2 types

• apocrine glands - secrete sweat into hair follicles, responsible for body odor

• eccrine glands - secrete sweat onto surface of skin, help to cool you down

• sebaceous gland - produce oil to keep hair flexible

• sensory receptors - nerves that sense touch, temperature and pain

• blood vessels - provide oxygen to skin cells

What is the subcutaneous layer?

• connects the dermis to muscle

• contains connective tissue, fat, nerves and blood vessels

What does your integumentary system do for you?

• Hair

• approximately 2.5 million hairs on the body

• found everywhere except palms of hands, soles of feet and lips

• develops from old, dead cells

• muscle and nerve connected to each hair

• hair provides sense, protection and insulation

• Nails

• protects the tips of fingers and toes

• contain keratin, which provides strength

• Can reflect health problems:

• bluish nails: circulatory problems

• white nails: anemia

• ridges or grooves: malnutrition

• red streaks: rheumatoid arthritis, high blood pressure

• clubbing: heart, lung, liver problems

• temperature regulation

• body heat is produced by muscle and liver cells

• skin helps keep the heat in

• body temperature is controlled by a part of the brain called the hypothalamus

• if body temperature gets too low, develop hypothermia

• cause mental confusion, loss of reflexes, shutting down of organs

• If body temperature gets too high, develop hyperthermia

• cause light headedness, dizziness, fatigue, nausea

How does your skin repair itself?

• laceration - a cut

• a cut into the epidermis will heal quickly

• a cut into the dermis will bleed, clot and take longer to heal

• a cut into the subcutaneous layer may require stitches or gluing

• 3 categories of burns

• first degree - only the epidermis is affected

• second degree - epidermis and part of the dermis is affected

• fluid develops between the two layers and blisters form

• third degree - damages all layers of the skin

• new cell growth is not possible

• requires a skin substitute to cover the skin and help with healing

What are common skin problems?

• Acne

• pimples for when glands become clogged

• can be hereditary

• most common cause is hormones

• Eczema

• severely dry skin

• can be hereditary or caused by allergic reaction

• requires moisturizing the skin and corticosteroids

• Sebhorreic dermatitis

• causes waxy, oily patches on the scalp

• common in infants, known as cradle cap

• can also appear in teens

• Skin cancer

• most common type of cancer in the US

• 3 types

• basal cell carcinoma

• squamous cell carcinoma

• melanoma - most deadly

• Psoriasis

• chronic disease that leads to the build up of excess skin tissue

• causes skin to appear red and be covered in silvery scales

What is a tattoo?

• permanent marking on the skin

• involves injecting ink into the dermis

• originated over 5000 years ago

• purpose varies with culture

What are the risks?

• allergic reactions to dyes

• skin infections (bacterial)

• bloodborne disorders (HIV, hepatitis, syphilis)

How are tattoos removed?

• excision - the tattoo is cut out and skin sewn back together

• skin graft - large tattoo is cut out and replace with skin from somewhere else

• laser - breaks tattoo ink into small particles, immune system removes them