HS1 INTEGUMENTARY

SYSTEM

7 Functions

1. Protection 2. Regulates body temperature 3. Manufactures Vitamin D 4. Sensory perception 5. Temporary storage of fat, glucose,

water and salts 6. Screens out harmful ultraviolet

radiation 7. Absorbs certain drugs

Layers of your Skin

3 Layers of your Skin

1. EpidermisOutermost covering Epithelial cellsAvascular

2. Dermis True skinConnective tissueVascular

3. Subcutaneous tissue

Layers broken down….

EpidermisLayers of the Skin

EPIDERMIS Thickness varies on location

*thinnest on eyelids

*thickest on palms of hands & soles of feet.

EPIDERMIS

4 cell types

1. Keratinocytes

produces keratin which keeps skin dry and is a barrier to UV & bacteria

2. Merkel Cells

Sensory receptors for touch

3. Melanocytes

Make protein “melanin” – give you your color. The more melanin the darker you are

Freckles = patches of melanin

4. Langerhans Cells

defend microorganisms

Epidermis cont… 5 layers

1. Stratum Germinativum (deepest)

2. Stratum Spinosum

3. Stratum Granulosum (keratinization begins & cells die)

4. Stratum Lucidum

5. Stratum Corneum

Epidermis cont…

Lower edge of layer #1 has ridges known as “papillae”

- very pronounced in fingers/soles/palms

-provide resistance to slipping for holding/grasping objects

-create individual fingerprints & footprints.

DermisLayers of the Skin Cont….

Dermis Consists of

Connective Tissue

Collagen tissue bands

Elastic fibers

Nerve endings

Muscles

Hair follicles

Oil & sweat glands

Fat Cells

Thickest over soles of feet & palms of hands

Dermis cont… Contains nerve receptors

• Sensory nerves – heat, cold, touch, pain and pressure

• Touch receptors close to the surface

• Pressure receptors are deeper

Blood vessels in dermis aid in the regulation of body temp. An or in outside temp makes blood vessels dilate to bring warmed blood flow to the surface of your body.

*SubcutaneousLayers of the Skin Cont…

Subcutaneous Also called

“Superficial fascia” or “Hypodermal” Layer

Not a true part of integumentary system (attaches dermis to surface muscles)

Subcutaneous

Consists of loose connective tissue

Contains ½ of body's stored fat.

Some injections can be given here (abbreviated SQ – given at 45 degree angle)

Appendages of the SkinIncludes Hair, Nails, Sweat Glands, & Oil Glands

HairAppendages of the Skin

Hair Almost everywhere on the body

(except palms, soles, glans penis, & inner vaginal labia) Length, thickness, type and color varies

Hair Length, thickness, type and

color varies Outer layer = CORTEX (as

one ages, pigment replaced with air and looks white/gray)

Inner layer = MEDULLA Part under the skin = ROOT Part outside the skin =

SHAFT (protects skin surface)

Hair cont…

FOLLICLE = pocket in epidermis, hair inside (determines straight or curly hair)

PAPILLA = tuft of tissue in root, contains capillaries

ARRECTOR PILI MUSCLE = attached on side of each follicle, when stimulated by a sudden chill it contracts and causes skin to pucker “Goosebumps”

NailsAppendages of Skin

Nails

Formed in the nail bed “matrix” Epidermal cells fuse together and fill

with keratin

Sweat Glands“SUDORIFEROUS

GLANDS”

Appendages of Skin

Sweat Glands Perspiration = sweat

(99% water) Distributed over the

entire skin surface Large numbers under

the arms, palms of hands, soles of feet and forehead

Sweat Glands Duct extends to form a

pore in the skin, perspiration excreted through the pores

May be activated by heat, pain, fever and nervousness

Average fluid loss is 500 ml per day

Oil Glands“Sebaceous

Glands”

Appendages of Skin

Oil glands

Secret oil (SEBUM) that protects and lubricates the skin

Keeps skin soft & pliable