Download Integumentary System

Ch. 5
What do you know about your
skin?:
 What is the branch of medicine that
specializes in skin disorders?
Dermatology
• About what percent of body weight does
the skin make up?
15-20 percent
 What is the skin most susceptible to?
infection, disease, injury
Ravaged
Scarred
But Repairable!
What is skin?
 Its an organ
 Made of cutaneous membrane. Superficial epidermis
made of stratified squamous epithelium and dense
connective tissue.
 Length of replacement? Youth: 28-30 days, Elderly 4550 days
Is skin the same thing as the
integumentary system?
 No.
 Skin is a cutaneous membrane
 Integumentary system includes sweat and oil glands,
hair, and nails.
 Integument= covering
What is the jobs of the skin?
Pg. 95
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Regulates heat loss.
Excretory functions for urea, salts, and water.
Water Retention
Manufactures proteins
Synthesizes vitamin D
Integrate with the nervous system for touch
sensation
What are the three layers of
the skin?
*
What is the job of the
epidermis?
 Keratinizes: becomes hard for
protection
 Avascular: only the lowest level of the
epidermis is close enough to capillaries to
gain nutrients. That means: the skin you
see is all dead! Shedding skin doesn’t
hurt!!!
 Contains Melanin: pigment produced by
melanocytes.
Layers of the Epidermis
Layers of Epidermis
Stratum Basale – deepest, only
epidermal cells
Stratum Spinosum-make
Keratinocytes
Stratum Granulosum-fuse cells
together
Stratum Lucidum – only on
hands/feet
Epidermis Skin Layers
Corneum
Lucidum
Granulosum
Spinosum
Basale
What is the job of the dermis?
 Its leather. Protective, strong, living, and
houses many other tissues.
 Sweat Glands: maintain body temp. Excrete
waste.
 Hair follicles/bulbs: for warmth
 Nerves: pain, pressure, temperature
 Blood vessels: maintain body temp
2 Regions of Dermis
Papillary layer
– contain capillaries for nutrients
for epidermis
pain and touch receptors
Regulates temperature
2 Regions of Dermis
Reticular Layer – deepest skin layer
Blood vessels, sweat and oil
glands, and deep pressure
receptors
Thick collagen strengthens skin
Papillary and Reticular Layers
Skin Color
Melanin (yellow, reddish brown, or
black)
Carotene
Oxygen bound to hemoglobin in
dermal blood vessels
Poorly oxygenated blood causes
cyanosis in Caucasians
What do Melanocytes do?
 Produces pigment to protect the cells DNA.
What is an appendage of the
skin?
 Append= to hang on
 These are things that “hang on” or
are attached to the skin.
 Appendages include: Glands, Hair,
and Nails
 All appendages are part of the
epidermis
What is the job of hair and hair
follicles?
 Guards the head and eyes as well as
respiratory tract from particles &
impact.
 Head Hair retains body heat. All
other body hair is a vestigial
feature.
 Hair Follicles grow hair
What are the parts of the hair follicle?
Pg. 96
 Root of hair is enclosed in the hair
follicle (The hair bulb matrix= zone of
growth which contains melanin).
 Hair grows up the shaft to the surface
of the skin.
 The bulk of hair is dead. There are 3
layers to hair: 1) Medulla, 2) Cortex, 3)
Cuticle (Protection against abrasion,
Damage=Split Ends)
Hair
What makes hair look
different?
 The amount of melanin secreted
 The shape of the hair is regulated by
the shape of the hair follicle which
changes the shape of the hair shaft.
 Round Hair (straight shaft)= Straight
and Coarse
 Oval Hair= Wavy and Smooth
 Curley Hair (hooked shaft)= Flat
What are the parts of the
nail?
 Used for protection
 The root of the nail is embedded in
the skin. Grows from the nail matrix.
The cells heavily keratinized, die.
 Extends along the nail bed.
 Lunula – moon shaped beginning of
nail Fig4.7 pg. 102 Lun= moon
Nail Growth
What do the cutaneous glands
do?
 Exocrine glands that secrete onto the
surface of the skin. Sebaceous & Sweat
 Sebaceous Glands- Produce oil all over
the body. Sebum used for softening,
water retention, killing bacteria.
Increases when testosterone is
produced= Oily skin.
 Sweat Glands- helps maintain
homeostasis
What are the two types of
sweat glands?
 Eccrine Glands: Cover Body, Contain
H2O, Salt, Vit. C, Wastes, Lactic Acid
 pH 4-6: antibacterial
 Sweat pores are not easily visible,
Contain nerve endings for regulation
And the Other One?
 Apocrine glands- auxiliary and
genital areas. Ducts empty into hair
follicles.
 Milky-yellowish in color, odorless.
Body odor occurs when bacteria eat
it. *Thought to be used in excreting
Pheromones
pheromones*
And Mates
Why do you not have wrinkles
when your young?
 Collagen fibers: Strong and keep the
skin hydrated (attract H2O).
 Elastic fibers: Keep skin elastic. Like all
elastic, it is less so with time.
 Loose fat in the hypodermis. = sagging
 Decrease in subcutaneous tissue, causes
dryness, cold sensitivity, and bruising in
the elderly.
What happens when the
epidermis and dermis
separate?
 A blister
 Caused by friction or burns.
What causes goose bumps?
Smooth muscles called Arrector
pili that attach to hair follicles
contract.
What is the job of the
hypodermis?
 Anchors the skin
 Shock absorber
 Insulates from temperature change
 Gives shape to fatty areas of the
body
Fat Lab
Time
Skin Pop Quiz
Brace Yourself
Problems of the skin
 Bedsores or Decubitus Ulcers- Caused by pinching off
of the blood supply to the skin. Occurs over bony
areas of the body. See figure 4.4 on Pg. 98
Alopecia
 Fancy word for balding
 By age 50, 1/3 of your hair follicles may be lost
 Severe alopecia can happen to anyone at any age and is
not thought to be genetic. ALL BODY HAIR is lost!!!
Infections and Allergies of Skin
Athlete’s foot (tinea pedis) – fungus
More Diseases
Boils and carbuncles –
inflammation of hair follicles and
sebaceous glands
And another Disease
Cold sores – herpes simplex virus
– activated by emotional upset, fever
or UV radiation
Infections and Allergies of Skin
Contact Dermatitis – itching,
redness, and swelling caused by
exposure to chemicals (poison ivy)
Still more Disease
Impetigo – pink, water-filled,
raised lesions that develop a yellow
crust and rupture – caused by
staphylococcus
Infections and Allergies of Skin
Psoriasis – chronic condition of
reddened epidermal lesions
covered with dry scales –
triggered by trauma, infection,
hormones, stress
Vitaligo
 Three possible causes
 Autoimmune attack
 Malfunctioning nerves
 Self destructive cells
 Some treatments such as creams are effective in early
stages.
 Can effect anyone.
What are the problems with
smoking and sun on the
epidermis?
 Leathery skin
 Cold sore (herpes outbreak)
 Depressed immune system
 All from DNA damage.
Review Burns and Skin Cancer
 What are the ABCD’s of Skin Cancer?
 What are the 3deg. Of Burn?
Burns
Skin
Cancer
Link
Skin Cancer
 Squamous Cell
Basal Cell
Administering Medications
Transdermal - skin patches for
nicotine, motion sickness, birth
control – slow absorption
Subcutaneous – insulin –
moderate absorption
Intramuscular – vaccines – rapid
absorption
Developmental Aspects
5th month – fetus covered with
downy hair (lanugo) that is shed by
birth
Adolescence – skin and hair
become more oily as sebaceous
glands are activated (acne)
Developmental Aspects
Aging – hair thinning and baldness
– males
Gray hair – decreasing amount of
melanin deposited – caused by
anxiety, protein-deficiency,
chemotherapy, excessive vitamin A,
genetics