Download lecture 4: integument system

LECTURE 4: INTEGUMENT SYSTEM
Now everything so far has been just an introduction. Now Anatomy class begins!
We’ll discuss the organ systems of the body one by one.
For each system, we’ll discuss its function, the individual organs, its tissues, and clinical
significance.
INTEGUMENT SYSTEM
1. Organs
a. Skin
b. Hair
c. Nails
d. Glands
2. Functions
a. Protection
i. Abrasion
ii. Infections
iii. UV light
iv. Dehydration
b. Thermal regulation (maintaining proper body temp)
i. Insulation = adipose layer
ii. Cooling = sweat glands
c. Sensory reception (touch, temp, pain, etc)
d. Vitamin D production (discussed in physiology)
e. Communication (when someone looks at you, what do they see? Smile,
frown, etc are forms of communication)
ORGANS OF THE INTEGUMENT SYSTEM
1. SKIN (has three layers)
a. EPIDERMIS (outermost layer. “epi” means above)
b. DERMIS (deep to epidermis)
c. HYPODERMIS (“hypo” means below. Hypodermis needle)
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Remember, the term “SKIN” refers to all three of the following layers: epidermis, dermis,
and hypodermis.
EPIDERMIS
1. Primarily made up of keratinized stratified squamous epithelium
2. The EPIDERMIS is the layer that gives strength to the skin.
3. The epidermis varies in thickness from a few to dozens of cells thick (eyelids to
palms)
4. It does not have any vascularization, so it relies on absorbing nutrients from the
tissues deep to it.
5. The nails are made in the epidermis.
6. All epidermis has four layers (thick skin has a fifth layer):
How to remember the layers of the epidermis
• The epidermis has five layers. From deep to superficial, they are the stratum
basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum
corneum.
• To remember which one is the deepest layer, visualize your basement. That is the
stratum basale.
• To get from your basement (deepest layer) to the roof (superficial layer), walk up
your basement stairs...be careful! They are covered with cactus spines (stratum
spinosum).
• That leads you to the kitchen, where someone has spilled sugar all over the floor
(stratum granulosum).
• Then you go upstairs and stop to put on suntan lotion before you go to the roof.
The stratum lucidum is like a layer of suntan lotion; it protects from UV rays, but
is only present on the palms and soles, so that's where you picture yourself
applying the lotion.
• Now you are ready to go to the roof and enjoy a nice corn on the cob (stratum
corneum).
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a. STRATUM BASALE
i. Main cell type is KERATINOCYTES
1. Keratin is a protein, is waterproof and strong
ii. MELANOCYTES produce MELANIN (dark brown pigment)
1. Everyone has the same number of melanocytes
2. Improper function causes light skin
iii. MERKEL CELLS (receptors for light touch in the stratum basale)
iv. MACROPHAGES (ingest debris)
b. STRATUM SPINOSUM
i. As new cells are made in the S. Basale, the older cells get pushed up
and become the S. Spinosum
ii. They are now attached to each other by desmosomes, which are
pointy/spiny (“spinosum”)
iii. They no longer divide
iv. They provide the strength to the epidermis
v. Langerhans’ cells here are white blood cells (immune system)
c. STRATUM GRANULOSUM
i. As more new cells are made in the S. basale, the S. spinosum layer is
pushed up to become the S. granulosum layer.
ii. The cells in the S. granulosum begin to die because they are now too
far from nutrient source (in dermis)
iii. After they die, they start to fill up with keratin
KERATIN
• Keratin is a waxy protein substance only found in the epidermis. It makes up the nails
and is also in each superficial skin cell.
• It can absorb water, so keratin swells when soaking wet. It makes the skin look
wrinkled when you are in the tub too long. The water evaporates when you dry off,
and pulls more water out of your body, so soaking in the tub will dry your skin
out…unless you put lotion on right away to keep the water in the epidermal and
dermal layers. Lotions will not penetrate to the dermis, just water.
d. STRATUM CORNEUM
i. As more new cells are made in the S. basale, the cells are all
pushed up again, and the S. granulosum layer becomes the S.
Corneum.
ii. The main difference between thick skin and thin skin relates to the
thickness of the Stratum corneum.
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iii. These are the dead cells, flaking off. In the stratum corneum the
cells lose their nucleus and fuse to squamous sheets, which are
shed from the surface in about 2 weeks (desquamation).
iv. It takes about 15-30 days for a cell to move from the stratum
basale to the stratum corneum and another 2 weeks to shed.
v. We lose 50 million cells a day, 1.5 grams
vi. They are the major source of dust in the house
vii. Dust allergies are actually from dust mites which eat the dead skin.
e. STRATUM LUCIDUM
i. This layer is only on the palms and soles
ii. It is just deep to the S. corneum and superficial to the S.
granulosum
iii. This THIN layer provides protection from UV radiation.
Why do black-skinned people have lighter colored palms and soles?
• Only the Stratum Basale has pigment-containing cells, but the stratum lucidum
contributes the color of protein, which is an orange- tan color.
• In the palms and soles, the stratum lucidum is present and it is a thick layer. The
tan colored protein blocks the underlying melanocytes from view.
NOTE: If you rub the skin, it stimulates cell division = callous
If you rub the skin too hard, the stratum basale tears away from the basement membrane,
and causes a gap, which fills with fluid. What’s this called? A BLISTER. The epidermis
then dies because it’s too far away from nutrients. That’s why the top of a blister dries up.
If the blisters are small (less than 5 mm in
diameter), they are known as vesicles; if
they are larger (greater than 5 mm in
diameter), they are termed bullae.
Individual skin cells do not have a high metabolic rate, and construction of scar tissue is
more difficult than making normal skin. Remember that the epidermis does not have as
much blood supply as the dermis, and the fibroblasts are only present in the dermis.
Still, the skin is capable of repair, even after serious damage because stem cells persist in
both the epidermis and the dermis.
Skin Cancer: This is the most common cancer in the USA, and the major risk factor of all
skin cancers is exposure to ultraviolet light.
The second most common type of cancer is lung cancer.
The least common (of the common cancers) is leukemia.
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Three major types of skin cancers:
1) BASAL CELL CARCINOMA: Cancer of the blood vessels in the dermis.
• The most common type of skin cancer, The most common type of skin cancer,
accounts for about 75% of the skin cancers.
• Almost never metastasizes or crosses the basement membrane, so is almost never
fatal.
• It is the most easily cured: surgical removal, no chemotherapy or radiation usually
needed.
• Symptoms are minor: shiny nodules, usually on nose or other sun exposed areas.
2) SQUAMOUS CELL CARCINOMA
25% of all skin cancers
Will metastasize if not treated.
Actinic Keratosis
• A premalignant condition of thick, scaly, or crusty patches of skin.
• It is more common in fair-skinned people, in sun-exposed areas of skin.
• 20% of these lesions progress to squamous cell carcinoma.
• They begin as flat, dry, scaly areas, and later grow into tough, wart-like lesions.
3) MELANOMA: cancer of the melanocytes of the epidermis;
least common (about 1% of skin cancer)
Highly metastatic, causes 75% of skin cancer deaths.
Asymmetrical, sharp but irregular borders and edges
Not uniform in color.
CONDITIONS OF THE SKIN
1. ECZEMA
• ATOPIC DERMATITIS
• CONTACT DERMATITIS
2. SEBORRHEIC DERMATITIS
3. PSORIASIS
4. VITELLIGO
TERMINOLOGY
• The medical term for a mole = nevus (plural = nevi)
• The medical term for a freckle or any other pigmented area that is flat and does
not stick upwards from the skin = macula
• Excoriations is the term for scratch marks on the skin.
• The medical term for dry skin is xerosis.
• There are many things that can cause xerosis.
• The medical term for inflamed skin is dermatitis.
• There are many things that can cause it.
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1. Eczema (itchy skin)
• Itchy red skin that comes and goes.
• Caused by an autoimmune reaction.
• The most frequently occuring form of eczema is atopic dermatitis.
Atopic dermatitis
• Triggered by allergens like soaps, cosmetics, clothing, detergents, jewelry, or
sweat.
• Can be triggered by changes in weather or stress.
• Tends to run in families.
• Treatment is lubricant creams daily and steroid creams during outbreaks.
Contact dermatitis
• Localized reaction from an allergy to something you touch.
• Poison ivy, oak, sumac cause this type of reaction.
• Everyone gets this reaction the second time they touch one of these
poisonous plants.
• People with a history of allergies are more likely to get contact dermatitis
from other things too, like plastic shoes, latex gloves, detergents, etc.
2. Seborrheic dermatitis (also itchy)
• Severe dandruff
• Caused by an allergy to the fungus that we all have around our hair roots.
• Causes severe dandruff that does not respond to regular dandruff shampoo.
• Treatment is shampoo with ketoconazole (steroid) or coal tar. Usually works for
one year, then you have to switch to another product for a year, then switch back.
3. Psoriasis (NOT itchy)
• An autoimmune disease of the skin.
• Causes flaking of skin, especially knees, elbows, scalp.
• There are treatments, but no cure.
• Treatments include shampoo with coal tar or steroids.
4. Vitelligo (not itchy)
• An autoimmune disease of the skin
• Destroys melanocytes, especially in areas of friction (eyelids, mouth, hands)
• Causes depigmentation.
DERMIS:
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1) PAPILLARY LAYER (Papillary = “Pimple”. Has bumps). More superficial layer
The papillary layer of the skin; LOOSE connective tissue.
A. Has ridges to increase surface area for contact with the epidermis
B. The papillary layer is in the DERMIS and is the actual layer responsible for the
fingerprints seen in the epidermis.
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Surgeons make incisions on the body based on the lines of cleavage of the skin
formed by the papillary layer of the DERMIS
Meissner's Corpuscle: nerve receptors in the papillary layer of the dermis for
light touch
2) RETICULAR LAYER
DENSE IRREGULAR connective tissue (although it tends to go in one direction)
Has lots of COLLAGEN and ELASTIN
• The DERMIS is where most of the body’s collagen is found.
Stretch marks are caused from tiny tears in the collagen of the dermis
Remember, the epidermis is the strongest layer of the SKIN, but the reticular
layer of the dermis is the strongest layer of the DERMIS. Gives the area strength.
Leather is made of this layer. When you wear a leather jacket, you are wearing a
dermis jacket!
• Pacinian Corpuscle: nerve receptors in the reticular layer of the dermis for
vibration and pressure
The dermis is also the area where all the glands of the body are located.
A transdermal patch (nicotine patch, etc) must diffuse all the way from the epidermis into
the dermis to reach the blood vessels there. The dermis has the blood vessels in it that
give Caucasian people the pink color to their skin.
What happens when you get cut?
Bleed, then clot
Macrophages eat foreign bodies and dead cells
Fibroblasts lay down collagen, a LOT more than normal; dense; SCAR.
If skin is cut with the grain, scar is not bad. Against the grain = worse scar.
Some people are more prone to scar tissue than others.
KELOID SCARS
 Thick, red, sometimes painful scars
 More common in African American, Native American, and Asian races
 Treatment with cortisone injections
Vitamin D is made in the dermis of the skin, after exposure to sunlight. It’s function is to
maintain optimal blood levels of calcium and phosphorus.
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ADHESIONS
Another type of scar tissue is called an adhesion. This is scar tissue in the deeper layers of
the body, such as right outside of the intestines, outside of the ovaries, etc. Some people
form adhesions spontaneously from the organs rubbing against each other. If the
adhesions cause symptoms, they might need a surgery to clean them away.
STRETCH MARKS
Caused by sudden weight gain (especially pregnancy)
Expansion of skin, collagen fibers in the DERMIS separate = stretch marks.
SCURVY
• Scurvy is a disease resulting from a deficiency of vitamin C, which is required for
the synthesis of collagen in humans.
• The chemical name for vitamin C, ascorbic acid, is derived from the Latin name
of “scurvy”.
• Scurvy often presents itself initially as symptoms of malaise and lethargy,
followed by formation of spots on the skin, spongy gums, and bleeding from the
mucous membranes.
• Spots are most abundant on the thighs and legs, and a person with the ailment
looks pale, feels depressed, and is partially immobilized.
• As scurvy advances, there can be open, suppurating wounds, loss of teeth,
jaundice, fever, neuropathy and death.
• Scurvy was at one time common among soldiers and sailors who were unable to
obtain perishable fruits and vegetables.
• Most animals can make their own vitamin C, so they don’t get scurvy.
• Vitamin C is destroyed by the process of pasteurization, so babies fed with
ordinary bottled milk sometimes suffer from scurvy if they are not provided with
adequate vitamin supplements.
• Virtually all commercially available baby formulas contain added vitamin C for
this reason, but heat and storage destroy vitamin C.
• Foods high in vitamin C
• Citrus fruits such as oranges or lemons, blackcurrants, guava, kiwifruit, papaya,
tomatoes, bell peppers, and strawberries.
• It can also be found in some vegetables, such as carrots, broccoli, potatoes,
cabbage, spinach and paprika.
HYPODERMIS:
Varies tremendously in thickness: Shins = thin; Buttocks = thick.
Functions
1) Stores fat
2) Cushions
3) Insulation of heat from blood vessels in this layer.
4) Stabilizes the position of the skin in relation to underlying tissues
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Hypodermis is not connected to underlying tissue, such as muscle. Therefore, exercising
muscle will not burn off fat only in that area. Fat is burned off equally over entire body.
Losing 10 lbs is like loosing ¼” off whole body. More noticeable in face than in hips.
By the way, there’s no such thing as cellulite. The term was invented by marketers. It is
NOT a special type of fat. It’s just fat, the same as every other fat. It looks wrinkled
because the collagen fibers on top of it bind it down like a net. No such thing as a cream
to get rid of adipose. (Don’t confuse cellulite with cellulose, a plant fiber)
LIPOSUCTION
• This is a surgical procedure where the patient has fat sucked out of the
hypodermis layer.
• Liposuction is dangerous because hypodermis is very vascular, can bleed too
much.
BURNS: Three types:
FIRST DEGREE: Minor burn to the epidermis; sunburn
SECOND DEGREE: Dermis separates from epidermis; blister
THIRD DEGREE: Hypodermis is burned. (most severe type of burn)
2˚ and 3˚ burns over a large part of the body gives a survival chance proportional to the
amount of skin left. 60% burn = 60% chance of dying.
Why are deep burns so dangerous?
1) Infection
2) Dehydration: nothing to keep fluid in body.
Skin grafts can be from a cadaver, artificial, or from another part of the body.
Skin grafts cause lots of scarring.
DECUBITUS ULCERS
Epidermis is destroyed, underlying tissue is exposed.
How decubitus ulcers form:
If you’re sitting down, weight of the body presses against blood vessels, no blood flow to
skin of buttocks. In you, it’s ok, because you’ll be walking around again in a half hour.
But if it goes on longer than a couple of hours because one can’t move, tissues can’t get
oxygen. Ulcer forms, can get gangrene or go systemic and die of infection. Whose fault
is it? The nurse’s, for not moving the patient every couple of hours.
SKIN COLOR; Caused by four things:
1) MELANIN: (dark brown pigment). More melanin, darker the skin.
2) CAROTENE: (a yellowish/orange pigment found only in plants). Accumulates more
in the skins of Asians and Native Americans.
3) SKIN THICKNESS: thinner skin see blood vessels, looks pinker
4) HEMOGLOBIN: The DERMIS contains the blood vessels that give Caucasians the
pink color to the skin. Even veins are red because blood is red. But when you look at
veins through the adipose layer, they look blue.
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CONTUSION: “Bruise”
• Why does a bruise look black and blue? The vessels in the hypodermis are
ruptured, and the blood leaks out; looks blue. As it ages, the hemoglobin breaks
down to a green color, then a yellow color.
• The age determines the color of the bruise.
CYANOSIS: Bluish color to skin.
Caused by superficial blood vessel constriction in the dermis or lack of blood flow to skin
Occurs for two reasons:
1) Cold
2) Not enough oxygen in body to go around. The oxygen is conserved for the vital organ,
so oxygen to skin and nails is shut down.
AGING
WRINKLES
Over time, collagen fibers align themselves more and more as they are always being
pulled in the same direction: smile, frown.
Skin begins to sag because body makes less elastin. Pinch your grandma’s skin. Does it
bounce back, or ooze back?
What can be done about wrinkles? Not much. Face lift clips off extra skin.
Creams don’t work. Trying to fix a collagen problem with a cream is like trying to
shampoo your carpet by putting the cleaner on the roof! As a matter of fact, collagen is
such a large molecule, and the pores that lead to the dermis are so small, it would be like
fitting a room into a cup.
BOTOX
This is a deadly poison which paralyses the muscles, making them sag. That releases the
tension, and relaxes the skin line. In 3 months, new muscle cells are made, so wrinkles
come back, and need new injection.
COLLAGEN INJECTION
Collagen is injected into hypodermis. Can last a couple of years.
MOISTURIZER CREAMS
The secret ingredient of all moisturizers is WATER. They work superficially on the
epidermis. Although keratin is waterproof, it swells when wet. So, if you put a
moisturizer on skin, stratum corneum expands, and hides wrinkles. Get the same effect
by soaking in the tub, and that’s cheaper. If you soak in water a long time, it over-swells,
and fingers appear deeply wrinkled.
TATTOOS
Pigment is injected into the dermis. If the needle is sterile, there’s no health risk.
However, the pigment diffuses with time. What looks good in your 20’s will look like a
blob when you’re 50.
Laser treatment is just burning the ink out of the dermis; may leave a scar. Depending on
the color of the tattoo ink, it may only cause it to fade.
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HEMANGIOMA: enlargement of the lining of blood vessels
• Laser treatment works well
HAIR
There are about 2 million hairs on the body; 200,000 on the scalp.
The arrector pilli are tiny muscles that cause the hair to stand up straight when we have
“goosebumps”.
The hair papillae are what are destroyed by electrolysis, so hair won’t grow back.
The hair matrix is the leading edge of the hair papilla. It is actually skin (keratocytes)
which are rapidly dividing. When they die, the new ones push them out, forming the
hair. Hair is just dead skin cells. The base of the hair shaft is the hair root.
The hair matrix is the part of the follicle that is the site of hair growth and the location
of the melanocytes that determine hair color. Hair that goes grey has lost its melanin
pigment. Differences in uncut hair length result from both variations in hair growth rate
and duration of the hair growth cycle.
Hair Loss
• Hair loss in men and women is due to the presence of a male hormone (an
adrogen) called DTH.
• Men who have gene for baldness show male pattern baldness.
• Women who have the baldness gene don’t have as much of the male hormone;
they just get thinning of the amount of hair.
• Women get the baldness gene from their father, and men get the gene from their
mothers.
• A man can tell if he will go bald by looking at his mother’s father.
• Hereditary hair loss and premature greying are some of the most common genetic
conditions.
• Hereditary baldness, in men also known as male pattern baldness, is not
exclusively a male concern.
• An estimated 25% of women suffer from female pattern baldness but, since their
hair loss is diffuse, it is not as easily recognizable as the male form.
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Life Cycle of Hair
• For most hair loss treatments to be effective, the hair's growth phase has to be
interrupted and the hair shed.
• Only the new budding hair that comes out of a hair follicle after a short resting
period can be of noticeably better quality than its predecessor.
• This replacement can sometimes come in a shock wave called shedding and it is
frequently misunderstood by hair loss sufferers as a negative reaction to the new
treatment and so the treatment is then discontinued.
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The life cycle of hair is divided into three phases. The actively growing (anagen)
phase, the transitional (catagen) phase and the resting (telogen) phase.
Growth phase: 3-6 years, growing 10mm a month. About 85% of the hair on any
head at any given time is in the growth phase.
At the end of this period, blood supply to the hair bulb slows down and eventually
stops.
As a result, the hair ceases to grow and moves into the transitional phase, which
lasts only about two weeks.
Resting phase: hair just sits on the head for about three months. Then, it falls out,
to be replaced by the next budding hair in the growth phase which begins to grow
from the same hair follicle.
These replacement hairs get finer and thinner due to an increase in an androgen
hormone (DHT) as a person ages.
In most settings of baldness, the hair follicle finally shuts down and refuses to
produce more hair to replace the ones that have fallen out.
Good treatment enables you to maintain the hair you have remaining. The
maximum improvement you can expect is to regain the hair you have lost in the
last three years.
Do not wait for too long. The later you start treating the baldness, the less
successful your treatment will be. Do not let your follicles die. You need at least
the vellus hair (peach fuzz) to start with.
Hair Loss Medicines
• Current antiandrogen modes of action include
• (a) preventing the creation of DHT
• (b) preventing DHT from binding to the receptor site
• (c) blocking activity in the androgen receptor itself.
• There are two FDA-approved oral medicines for treating hair loss: Finasteride
(Propecia) and Minoxidil (Rogaine).
• FINASTERIDE (Propecia)
• It is the first and only FDA-approved pill proven to treat male pattern hair loss on
the vertex and middle front of head.
• The great majority of dermatologists agree that this is currently the No.1 cure for
hair loss.
• In tests, 66% of men grew hair in back and 42% grew hair up front. Almost all the
rest stopped losing hair.
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It cannot be used by women.
Dutasteride is another pill that may be receiving FDA approval soon. It appears to
be at least as powerful as finasteride, but it is more expensive.
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MINOXIDIL (Rogaine) comes as a pill and a topical foam that are both used by
the patient. It is available over the counter.
Minoxidil is a vasodilator that was originally used to treat severe blood pressure.
Its bizarre side effects, such as the ability to reverse or slow down the balding
process, were accidentally discovered in the late 1970s.
Minoxidil promotes enhanced follicular size, resulting in larger hair shaft
diameters. It also stimulates and prolongs the growth phase of the hair growth
cycle. It takes 4 months to notice results
Rogaine's effectiveness is established in front and back for women but only in
back (vertex) for men.
After 1 year of use, 48% reported moderate to dense re-growth of hair, 36%
reported minimal re-growth, and 16% reported no re-growth.
Once started, topical minoxidil treatment is a lifetime commitment if the
treatment proves effective. If regular application of topical minoxidil is halted, all
hair grown in response to the therapy will be rapidly lost over the next 3 to 6
months.
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SPIRONOLACTONE is a diuretic used to lower high blood pressure. In
addition, it possesses anti-androgenic properties as it binds to the androgen
receptor in the hair follicle and thus prevents it from interacting with DHT.
Hence, spironolactone is also used to treat acne, hirsutism (excess body hair) and
hair loss in women.
It is not for oral use by men, because it causes impotence, loss of sex drive, and
breast development.
Chemotherapy causing hair loss
• Chemotherapy causes hair loss because the drugs target any cell that is rapidly
dividing.
• Since the hair roots divide rapidly, they are killed off along with the cancer cells.
• The stomach lining is also rapidly dividing, so they also get nausea.
Fun fact: Men without hair on their chests are more likely to keep the hair on their head,
but are more likely to get cirrhosis of the liver. Men with hairy chests are more likely to
go bald.
Electrolysis
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Electrolysis involves sticking a fine wire into the follicle and administering an
electrical current to kill the hair papillae.
Treatments are repeated weekly for up to 18 months.
Hair follicles that are in the telogen phase are more difficult to destroy than hair
follicles in the anagen phase.
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Shaving approximately 3 days before an electrolysis treatment ensures that the
hairs that are visible are in the anagen phase.
Finally, side effects can include pain, infection, keloid formation (for people who
are susceptible), hyperpigmentation, or hypopigmentation.
Piebaldism: a rare autosomal dominant disorder of melanocyte development, causing a
congenital white patch of hair.
HAIR FOLLICLES
How does heat straighten hair?
• There are three types of bonds that make up hair. Salt bonds are broken by heat.
When the heat hits the hair the salt bonds break. When the hair cools the bonds
rebuild themselves in its new shape.
• Chemicals can be applied to hair to straighten it or to curl it. The chemicals break
the stronger bonds in the hair and cause the bonds to reform in the desired
position.
• Coloring hair strips the color from the shaft and replaces it with a dye. The new
color may fade with time.
STRUCTURES ASSOCIATED WITH HAIR FOLLICLES
1. SEBACEOUS GLANDS These glands are found all over the body, and they
produce sebum, which is oil that coats the hair and epidermis. It keeps the skin from
getting dry and brittle. The problem is that when you wash it away, the skin gets dry.
The best moisturizer is lanolin, which is made from sheep sebum.
PIMPLES
• Some of the largest sebaceous glands are associated with the smallest hairs (face).
• Pimples begin when oil gland ducts (sebaceous glands) become blocked by
viscous (thick) sebum and the gland swells.
• The sebum in the gland is exposed to oxygen and turns black, called a blackhead.
• The black part of a blackhead is oxidized sebum.
• In puberty, there is an increase in hormones, and an increase in gland production
leading to pimples.
Acne Vulgaris
• Acne develops as a result of blockages in hair follicles.
• Hyperkeratinization and formation of a plug of keratin and sebum (a
microcomedo) is the earliest change.
• Enlargement of sebaceous glands and an increase in sebum production occur with
increased androgen (DHEA-S) production at adrenarche.
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The microcomedo may enlarge to form an open comedone (blackhead) or closed
comedone (milia).
Comedones are the direct result of sebaceous glands' becoming clogged with
sebum, a naturally occurring oil, and dead skin cells.
In these conditions, the naturally occurring largely commensal bacterium
Propionibacterium acnes can cause inflammation, leading to inflammatory lesions
(papules, infected pustules, or nodules) in the dermis around the microcomedo or
comedone, which results in redness and may result in scarring or
hyperpigmentation.
Acne Vulgaris: Cause
• GENETIC
• The tendency to develop acne runs in families.
• PSYCHOLOGICAL
• It is associated with increased stress levels
• DIETARY
• A high glycemic load diet is associated with worsening acne. There is also
a positive association between the consumption of milk and a greater rate
and severity of acne. Other associations such as chocolate and salt are not
supported by the evidence. However, products with these ingredients often
contain a high glycemic load.
• HORMONAL
• Hormonal activity, such as menstrual cycles and puberty, may contribute to the
formation of acne.
• During puberty, an increase in male sex hormones called androgens cause the
follicular glands to grow larger and make more sebum.
• Use of anabolic steroids may have a similar effect.
• Development of acne vulgaris in later years is uncommon, although this is the age
group for rosacea, which may have similar appearances.
• True acne vulgaris in adult women may be a feature of an underlying condition
such as pregnancy and disorders such as polycystic ovary syndrome or the rare
Cushing's syndrome.
• Menopause-associated acne occurs as production of the natural anti-acne ovarian
hormone estradiol fails at menopause.
• The lack of estradiol also causes thinning hair, hot flushes, thin skin, wrinkles,
vaginal dryness, and predisposes to osteopenia and osteoporosis as well as
triggering acne (known as acne climacterica in this situation).
• When a pore is blocked, P. acnes, an anaerobic bacterium, overgrows and secretes
chemicals that break down the wall of the pore and form an acne lesion
(folliculitis).
• This leads to the possible spilling of bacteria such as Staphylococcus aureus into
the broken skin.
• Preliminary research shows healthy pores are only colonized by P. acnes while
unhealthy ones universally include the non-pore-resident Staphylococcus
epidermidis, amongst other bacterial contaminants.
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•
•
•
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P. acnes can be killed by benzoyl peroxide, tetracyclines , Clindamycin,
azithromycin, Fluoroquinolones such as nadifloxacin, ciprofloxacin, ofloxacin
and levofloxacin.
These are normally prescribed 500 mg by mouth, three times weekly for 4 to 6
weeks.
There are also many antibacterial preparations, including clove oil, PCMX, and
chlorhexidine gluconate.
Tetracycline-resistant P. acnes is now quite common.
BOILS (Furuncles)
• Unlike pimples, boils are caused by bacteria that enter a gland and invade into the
hypodermis.
• They are local infections that swell to a size that is larger than pimples.
• They are not blackheads.
• Most boils run their course within four to ten days. For most people, self-care by
applying a warm compress or soaking the boil in warm water can help alleviate
the pain and hasten draining of the pus ("bringing the boil to a head").
• Once the boil drains, the area should be washed with antibacterial soap and
bandaged well.
• In serious cases, prescription oral or topical antibiotics are used.
Carbuncles
• A carbuncle is a mass of boils which drains pus onto the skin. It is usually caused
by bacterial infection, most commonly Staphylococcus aureus, or Streptococcus
pyogenes, which can turn lethal.
• The infection is contagious and may spread to other areas of the body, or other
people; those living in the same residence may develop carbuncles at the same
time (mass of boils)
2. NAILS
The EPIDERMIS gives rise to the nails. At the nail root, there is rapid division of
keratocytes, and as they die, the skin moves up and creates the nail. Taking calcium
won’t make the nails any stronger because there is no calcium in keratocytes.
The proximal nail fold (cuticle) is called the eponychium.
The white half-moon visible under the proximal part of a fingernail is the lunula.
GLANDS
1. SEBACEOUS GLANDS are found all over the body, and produce oil that
coats the hairs and lubricates the skin.
2. ECCRINE (MEROCRINE) SWEAT GLANDS. These are found all over the
body, and produce a watery secretion which evaporates and cools the body.
3. APOCRINE SWEAT GLANDS are associated with pubic hairs in the axilla and
pubic region, as well as the mammary glands. The ones associated with pubic
hairs produce a secretion to coat the hairs. The hairs function as a wick to draw
the secretions to the surface. These glands also produce a type of protein (a
hormone once it is inhaled) known as a PHEROMONE.
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a. Pheromones function. for sexual attraction. There is no conscious odor.
The smell from the axilla is from bacteria that are attracted by the gland.
Expensive perfumes have pheromones. Guess where they get them from?
The anal glands of male cats! They are designed to attract females. They
are used so women will buy expensive perfume.
b. Pheromones also function to regulate menstrual cycles of females. If you
put several women in one room for months, their menstrual cycles will all
start to occur at the same time.
4. MAMMARY GLANDS are apocrine glands. They secrete milk. Each breast
has dozens of glands with their own duct to the surface in the nipple and areola.
In a woman who is not lactating, the majority of tissue is adipose. To change the
size of breasts, lose or gain weight! Breast implants go underneath the muscle
under the breast.
5. CERUMINUS GLANDS are only found in the ear, and they produce wax.
a. They keep the ear canal from drying out
b. They prevent insects from crawling in; they don’t like walking on the wax.
Other glands to know:
EXOCRINE GLANDS secrete substances into a duct within the cell itself.
ENDOCRINE GLANDS secrete hormones into the blood.
A GOBLET CELL secretes mucus.
A PLASMA CELL is a type of blood cell that secretes antibodies. We’ll talk more about
that when we get to the cardiovascular system.
CANCER
.
Cancer starts out as a mutation in one gene in one cell. Then the mutated cell starts
dividing itself rapidly and taking over the whole area.
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LEUKEMIA is a cancer in blood-forming cells.
LYMPHOMA is a tumor developing in lymphatic tissues.
CARCINOMA is a tumor developing in any part of the epithelium.
MELANOMA is a tumor developing in the pigment of the skin.
SARCOMA is a tumor developing in muscles and connective tissues.
CHARACTERISTICS OF CANCER CELLS
1. LACK DIFFERENTIATION
Normal cells have specialized functions, but cancer cells do not differentiate and do not
contribute to the function of the body.
2. ABNORMAL NUCLEI
They have large or multiple nuclei with mutated chromosomes.
3. FORM TUMORS
Cancer cells grow and divide rapidly until they accumulate and form a lump of cancer cells
called a tumor. A BENIGN tumor is an accumulation of non-cancerous cells because they
stay in their own capsule (encapsulated) and do not invade.
MALIGNANT tumors are cancerous cells that spread and invade.
4. ANGIOGENESIS (INDUCE BLOOD VESSEL FORMATION)
Since these tumors need nutrients, they create new blood vessels just for them to feed on.
5. METASTASIZE
Pieces of the tumor break off and travel in the bloodstream to any new location, invade
nearby tissues and continue their massive cell division and growth there. If there is a
tumor in the lung, it is biopsied (the doctor surgically takes out a piece). If the cells are
lung cells, it is lung cancer. But if the cells are pancreas cells, it is pancreatic cancer that
has metastasized.
ORIGIN OF CANCER
There are many factors that play a role in the development of cancer, including heredity
factors, carcinogens, and mutagens.
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CARCINOGEN is an environmental agent that contributes to cancer
Examples of a carcinogen are radiation, toxic chemicals, and viruses.
MUTAGEN is an agent that increases chances of DNA change or mutation.
Cancer cells arise from mutated chromosomes. This is caused from either hereditary
factors or cancer-causing agents (carcinogens) in the environment.
1. CARCINOGENS
a) RADIATION is from overexposure to sunlight or x-rays.
b) ORGANIC CHEMICALS include tobacco, foods, and pollutants
2. HEREDITY
Particular types of cancers run in families, such as breast, lung, and colon cancer.
DIAGNOSTIC PROCEDURES
PAP SMEARS detect cervical cancers. They just swab the cervix and look at the cells
under a microscope.
MAMMOGRAMS are diagnostic procedures to detect breast cancer. The breast is just
placed on a special type of machine like an x-ray.
COLONOSCOPY is a diagnostic procedure to detect colon cancer. A scope is inserted
into the rectum so the doctor can look for polyps.
The American Cancer Society says the following are signs of cancer:
Change in bowel or bladder habits
A sore that does not heal
Unusual bleeding or discharge
Thickening or lump in breast or elsewhere
Indigestion or difficulty swallowing
Obvious change in wart or mole
Nagging cough or hoarseness
PREVENTION
1. BEHAVIORS
DON’T smoke, sunbathe, drink alcohol, or get too many x-rays. Smoking cigarettes is
associated with many types of cancers, including cancer of the lung, larynx, throat, and
urinary bladder.
DO be tested (self-breast exams and Dr. check-ups), be aware of chemical hazards at
work, and be aware that using estrogen for menopause symptoms must be combined with
progesterone, otherwise there is an increased risk of cancer. The American Cancer
Society recommends breast self-exams and testicular self-exams every month.
2. DIET
Avoid fats, salty, smoke-cured, pork, and pickled foods. Eat plenty of fiber, green leafy
vegetables and fruits, and eat cabbage, broccoli, Brussels sprouts, and cauliflower. There
are things you can change in your diet that help prevent cancer. Green leafy vegetables
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such as cabbage and broccoli are associated with cancer prevention, as are vitamins A
and C.
PREVENTION OF SKIN CANCER:
A. use broad-spectrum sunscreen
B. stay out of the sun altogether from 10-3
C. wear protective clothing
D. wear sunglasses
E. do not use tanning machines
TREATMENT OF CANCER
1. RADIATION
When someone has surgery to remove a tumor, it is often followed by radiation because
the cancer cells may have spread throughout the body. Cells that are in the process of
dividing are the most likely cells to be killed by exposure to radiation. Since cancer cells
are always in the process of dividing, exposing them to x-rays may kill them. The x-ray
beam is coned down so just the tumor is exposed. However, scatter radiation kills off
other cells that rapidly divide (stomach lining and hair follicles), so the side effects
include baldness and nausea.
2. CHEMOTHERAPY
This is for cancer that has metastasized. It is also good for cancer of the blood (leukemia).
The drugs are designed to specifically kill just the cancer cells, but it tends to also kill off
the normal blood cells that are just being formed in the bone marrow. Thus, bone marrow
transplants are also needed sometimes.
3. BONE MARROW TRANSPLANTS
Someone needs to volunteer to donate a small piece of bone from the crest of their hip.
This bone marrow will contain healthy new blood cells that can repopulate the depleted
bone marrow of the sick person. These cells are injected into the sick person’s vein.
4. IMMUNOTHERAPY
Blood cells are taken from the sick person and are fused with an antibody that is
specifically designed to seek out and destroy the cancer cell.
5. GENE THERAPY
This is new research, attempting to find a gene that will shrink tumors.
6. COMPLEMENTARY THERAPIES
This involves natural healing therapies such as biofeedback, acupuncture, and exotic
foods. It’s worth a try if you’re going to die!
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