INTEGUMENTARY SYSTEM

Cutaneous membrane

• Skin

• Largest organ

• Covers an area of about 2 square meters

• Weighs 4.5 to 5 kg

• Serves as a barrier

• 1st line of defense for you body

SKIN

• Skin is our protective covering.

• It has 2 names– Integument – Integumentary system

Integumentary system

• Formed by the skin and its derivatives– Sweat glands– Oil glands– Hair– nails

Factoids

• You will shed about 40 pounds of skin in a lifetime

• There are over a million dust mites, microscopic organisms on you mattress and pillow eating the dead skin cells you shed during the night.

Factoids

• Skin must be cleaned regularly or it will become cracked or inflamed.

• Dead cells along with the dead skin cells are a food source for bacteria called a slurry. This slurry will emit a foul smell.

• As you age, skin becomes thinner and is easily damaged. It will sag due to loss of elasticity.

INTERESTING FACTS

• A human loses an average of 40 to 100 strand of hair a day.

• A fetus acquires fingerprints at the age of 3 months

• Every person has a unique tongue print.

• An average human scalp has 100,000 hairs.

• By the age of 60, most people have lost ½ of their taste buds.

• Every square inch of human skin consists of 20 feet of blood vessels.

• Every square inch of the human body has an average of 32 million bacteria on it.

• Fingernails grow faster than toenails

• Humans shed about 600,000 particles of skin every hour.

• That’s about 1.5 pounds a year.

• By the age of 70 years of age, an average person will have lost 105 pounds of skin.

SEVEN FUNCTION OF THE SKIN

• Protection• Body temperature

regulation• Waterproof• Excretion and

absorption

• Helps to manufacture vitamin D

• Cutaneous sensations– Site of many nerve

endings

• Temporary storage of fat glucose, water, and salts such as sodium and chloride

• Screens out harmful ultraviolet radiation (UV) contained in sunlight.

• It can absorb certain drugs and other chemicals

Layers of skin

• DERMIS– 2nd layer– Has wider variety of

sensory receptors– Contains dense

connective tissue

• EPIDERMIS– Outer most– Has sensory receptors– Contains stratified

squamous epithelial cells

Layers of epidermis

• 5 layers

• In order from deep to superficial– Stratum basale– S. spinosum– S. granulosum– S. lucidum– S. corneum

S. Corneum

• Dead cells

• Outermost layer

• waterfproof

• Cells rub off

• Replaced every 35-45 days

LUCIDUM, GRANULOSUM, SPINOSUM

• Cells become flattened

• become full of keratin

• die

S. Basale

• Composed of single rstem cells that undergo cell division to continually produce new kertinocytes.ow of cuboidal or columnar keratinocytes.

•

EPIDERMIS

• Avascular• Contains melanocytes

– Cells that make melanin

• Keratinocytes– Most epidermal cells– Produce keratin which is a protein that helps to give

epidermis its protective layer

• As these cells are pushed upward, keratin will become the dominant structure in the cells.

Melanin

• Responsible for the color of skin, eyes, hair

• Melanocyte– Cell with projections that weave between

other cells– Produce melanin

• Melanocytes are in greatest concentration in nipples, anal region, and armpits

• Protects from UV radiation

• Pigment ranges from yellow to black

• Pigment protects from UV

• Freckles/moles – Melanin concentration in one spot

• Over exposure to UV can cause cancer.

Langerhans cells

• Langerhans – easily damaged by UV

• works with immune system against microbes that invade the skin

Merkel cells

• Merkel cells contact the flattened process of a sensory neuron called a tactile (Merkel

PARTS OF THE SKIN

Label the diagram and give the function of the following parts

PARTS OF THE SKIN

• Epidermis• Dermis• Hair shaft• Papillae• Arrector pili muscle• Sebaceous gland• Sweat gland• Pore• Subcutaneous layer

• Nerve

• Blood vessels

• Adipose

DERMIS

• Composed of areolar connective tissue containing collage and elastic fibers

• Dermal papillae section with small fingerlike projections that indent the epidermis. – Meissner corpuscles– Free nerve endings

Reticular layer

• Deeper layer of dermis

• Contains blood vessels

• Sweat / oil glands

• Deep pressure receptors

• Hair follicles

• Collage and elastic fibers in the region provides the skin with strength and extensibility and elasticity

Accessory structures of skin

HAIR

• Protects the body

• Not present on palms, palmar surfaces of fingers, soles and plantar surfaces of toes

• Head region – guards the scalp from injury and the sun’s rays

• Eyebrows / eyelashes – protect the eyes

• Nostrils – protects against inhaling insects and foreign particles

Hair structures

• Cuticle – single layer of cells (shingles)– Cntains keratin– As it wear away hair gets fizzy and gets split

ends

• Cortex – inner layer

• Medulla – central core

• Shaft – central portion and is above the suface

• Root – portion below the surface and penetrates into the dermis and subcutaneous layer

• Hair follicle – surrounds root– Contains growth region

• Arrector pili - when contracted it causes hair to stand up – goose bumps

Glands

• Sebaceous galnds

• Sudoriferous glands– Eccrine– Appocrine

• Ceruminous glands

Sebaceous glands

• Oil glands

• Found all over the skin, except palms and soles

• Ducts empty into the hair follicle

• Some open directly onto the dkin

• Sebum

Sebum

• Product of sebaceous glands

• Oily

• Contains chemicals that kill bacteria

• Lubricant – Keeps skin soft, moist– Keeps hair from becoming brittle

• More active during adolescence

Sudoriferous glands

• Sweat glands

• Widely distributed in skin

• Two tyes– Eccrine– apocrine

Eccrine glands

• Most common• Start to function soon after birth• Found all over body, except margins of

lips, nail beds of fingers, toes, glans penis, glans clitoris, labia minor, and eardrums

• produce sweat – contains water, salts, urea, uric acid, vit. C

• pH 4 to 6• Regulates body heat

Apocrine Sweat Glands

• Found in the skin of the armpit, groin, areolae of the breasts, bearded regions of the face in males.

• Duct empties into hair follicle• Secretion - fatty acids and proteins along with

normal substances found in sweat• Bacteria live on skin and when they break down

these secretion, body odor results• Stimulated during emotional stress, sexual

excitement• Do not begin to function until puberty

Ceruminous glands

• Se-ROO-mu-nus glands

• Present in external auditory canal

• \combination of secretions of ther ceruminous and sebaceous glands

• Called earwax

• Forms a sticky barrier against foreigh bodies.

Additional sensory receptors

• Free nerve endings– Simplest– No structural specializations – Receptors for pain, thermal, tickle, itch, and

some touch sensations

• Encapsulated – Dendrites are enclosed in a connective tissue

capsule

Touch

• Meissner corpuscles

• Hair root plexuses

• Merkel disks

• Ruffini corpuscles

Pressure / vibration

• Pacinian (pa-SIN – e – an )

•

Skin color

• 3 pigments– Melanin– Carotene – yellow orange pigment. – Hemoglobin – oxygen carrying pigment in

RBS

• Freckles

• Age spots

Disease / disorders

• Skin graft• Psoriasis• Jaundice• Cyanotic• Hirsutism• transdermal drug administration• Albinism• Decubitus ulcers• wart

Burns

• Burns are traumatic injury as the result of radiation from the sun, heat lam or contact with boiling water, steam, fire, chemicals, or electricity.

• When the sin is burned, dehydration, and infection may occur.

• Either condition is life-threatening

Degree of burns

• First

• Second

• Third

Skin cancer

• Associated with exposure to UV light

Common types of skin cancer

• Basal cell carcinoma

• Squamous cell carcinoma

• Malignant melanoma

What to look for

• Brown or black irregular parch which occurs early

• Color or size change in preexisting wart or more

The skin and its relationship to microorganisms

• An intact skin is the best way the body can protect itself against pathogens and water loss.

• Cracking of dry skin can be prevented by lotions and creams

• The skin’s surface is not a favorable place for bacteria to grow because it is too dry.

• Skin bacteria grows where there is nutrients and moisture present.

• Most bacteria are found where the hair follicles and sweat glands are located.

• Underarm perspiration odor is caused by the interaction of bacteria on perspiration.

• This can be prevented by washing and using deoderants.

HANDWASHING

• #1 way to prevent the spread of disease.

• 10 – 30 seconds normal

• 2 – 4 minutes if you are in contact with infectious material.

• Exposure to blood or body secretions – wash hands, apply gloves, remove gloves and rewash hands.

AGING

• Most visible sings of aging are visible on the skin.

• Secrete less oil therefore skin becomes dry and more fragile.

• Skin loses elastin fibers causing the skin to lose elasticity.

• Loss of subcutaneous fat causes wrinkles, lines, and sagging.

• The dermal vascular network decreases in its ability to respond to heat and cold.