Transcript Integumentary and Skeletal Systems

Unit 3
Integumentary and Skeletal Systems
Part 1:
Integumentary System
Integumentary System
 The integumentary system consists of the skin, hair, nails,
and glands.
 Functions:
1. protection of internal structures (from abrasion & UV light)
2. prevention of infectious agent entry
3. regulation of temperature
4. production of vitamin D
5. prevention of water loss
6. detection of stimuli such as touch, pain, and temperature
Integumentary System
 Hypodermis:
 also called subcutaneous tissue or superficial
fascia
 It is not part of the skin, but usually is considered
with it because it attaches the skin to underlying
muscle, bone, or other connective tissue
 loose connective tissue that contains collagen and
elastic fibers
 contains about half of the body's stored fat
 important for padding and insulation
 responsible for some of the differences in
appearance between men & women & between
individuals of the same sex.
Integumentary System (Skin)
 Skin
Epidermis
(stratified squamous epithelium)
Two major tissue layers:
 Epidermis
(stratified squamous epithelium)
 Dermis
(dense connective tissue)
Dermis
(dense connective tissue)
Integumentary System (Dermis)
 Dermis
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dense, irregular connective tissue
responsible for most of the structural strength of the skin
Common use of the dermis: leather (tanned animal dermis)
consists of collagen and elastic fibers
contains fibroblasts, fat cells, and macrophages
On the upper part, has dermal papillae (projections which extend
toward the epidermis)
 Contains many blood vessels that supply the epidermis with nutrients,
removes waste products, & aids in regulating body temperature
 The dermal papillae in the palms of the hands, soles of the feet, & tips
of the fingers are in parallel, curving ridges that shape the overlying
epidermis into fingerprints & footprints. (The ridges increase friction
& improve the grip of the hands & feet.
Integumentary System (Dermis)
 There are two layers of the dermis:
 The reticular layer is the main fibrous layer and consists mostly of
collagen. It is the deeper layer and blends into the hypodermis.
 The papillary layer is well supplied with capillaries. It is the more
superficial layer and derives its name from projections called dermal
papillae that extend into the epidermis.
 If the skin is overstretched for any reason, the dermis can be
damaged, leaving lines that are visible through the epidermis. These
lines, called striae or stretch marks.
Integumentary System (Epidermis)
 Characteristics of the Epidermis (“upon + skin”):
 stratified squamous epithelium separated from the dermis by a basement membrane
 It is avascular - contains no blood vessels and derives nourishment by diffusion from
capillaries of the papillary layer
 cells are produced in the deepest layers by mitosis (FYI: your skin is replaced
approximately every 40-56 days!)
 as new cells are formed, they push older cells to the surface, where they slough (flake)
off - did you know that you will lose approximately 8 pounds just in dead skin cells in one
year?
 during migration from “deep” to “superficial” cells change in shape and chemical
composition
 thick skin is found on the palms of the hands, souls of the feet, and tips of the digits
Integumentary System (Epidermis)
 Keratinization:
 process that epidermal cells undergo as they move
to the surface
 produces cells filled with protein (keratin)
 gives the stratum corneum its structural strength
 produces an outer layer of epidermal cells that
resist abrasion & acts as a permeability barrier
 Epidermis divided into regions or strata
(from deep to superficial):
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stratum basale or germinativum (SG)
stratum spinosum (SS)
stratum granulosum (SGR)
stratum lucidum (absent in thin skin)
stratum corneum (SC)
 "Before Signing, Get Legal Counsel"
(Mnemonics to learn deep to superficial)
Layers of the Epidermis
Integumentary System (Skin Color)
 Skin Color:
 determined by pigments in the skin
 by blood circulating through the skin
 by the thickness of the stratum
corneum
 melanin, a brown-to-black pigment, is
produced by melanocytes in the
stratum basale
Integumentary System (Skin Color)
 melanin is transferred to other cells by
melanocytes
 melanin is present in large quantities in
moles, freckles, the genitalia, and nipples
 melanin production is genetically
determined, but can be influenced by
hormones and ultraviolet light
 albinism a recessive genetic trait that causes
a deficiency or absence of melanin
 albinos have fair skin, white hair, and
unpigmented irises in the eyes
Melanin Transfer from
Melanocyte to Epithelial Cells
Melanocytes make melanin, which is packaged into melanosomes &
transferred to many epithelial cells.
Integumentary System (Skin Color)
 Redness of the skin can occur from:
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the inflammatory response
anger or blushing
exposure to heat
exposure to cold
 Skin Conditions:
 decreased blood flow causes a pale skin (shock)
 decreased oxygen content in the blood results in a bluish color called
cyanosis
 a yellowish skin color, jaundice, can occur when the liver is damaged by a
disease such as viral hepatitis
 the disease scarlet fever results from a bacterial infection in the throat
 the condition of age spots are caused by increased melanocytes
Integumentary System (Skin Color)
Birthmarks = congenital disorders of capillaries in
the dermis
IV. Accessory Skin Structures
A. Hair
1. Characteristic of all mammals
a. Thick hair = fur
2. Hair anatomy:
a. Hair shaft = portion of hair above skin surface
b. Hair root = portion of hair below skin surface
c. Hair bulb = base of hair root
d. Medulla= center of hair
e. Cortex (bark) = surrounds the medulla
f. Cuticle (skin) = single layer of overlapping cells
holding hair follicle
g. Hair follicle = extension of epidermis deep into
dermis
i. Plays role in tissue repair
3.
Hair growth:
a.
Cyclic: growth stage + resting stage
i. Hair bulb produces hair; nourished by blood vessels
ii. Epithelial cells undergo keratinization in hair bulb;
cells are added to base of hair – hair “growth”
iii. Growth stops during resting stage
iv. Next growth stage causes hair to fall out
Hair Type
Growth Stage
Resting Stage
Eyelash
30 days
105 days
Scalp
3 years
1-2 years
i.
4.
Pattern baldness – permanent loss of hair
Hair color determined by varying amounts & types
of melanin
a.
Melanin production decreases with age = gray/white
B.
Muscles
1.
Arrector pili (that which
raises, hair) = contraction of
these muscles cause hair to
“stand on end”…
goosebumps 
a.
b.
Composed of smooth
muscle
Evolutionary advantage in
mammals – traps air (heat)
for insulation, also look
larger - intimidation
C. Glands (Exocrine – secrete onto a suface)
1. Sebaceous glands
a. Simple, branched acinar/alveolar
b. Produce sebum – oily substance lubricating hair & skin
surface, preventing drying out & protection against some
bacteria
C. Glands, continued…
2.
Sweat glands (two types):
a.
Merocrine sweat glands
i. Simple, coiled tubular w/ ducts opening to skin surface
ii. Every part of skin, most abundant in palms/soles
iii. Produces sweat: slightly salty water-based secretion
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b.
Evaporative cooling
Emotional stress produces sweat in palms, soles, axillae (used in lie
detector tests!)
Apocrine sweat glands
i. Simple, coiled tubular gland with ducts opening into hair follicles of
the axillae & pubic region
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ii.
Become active at puberty due to sex hormone influence
Secretes thick organic substances
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Broken down by bacteria = body odor
Sensory Receptors of the Skin
 Perceive Touch:
 Merkel’s Discs
 Meissner’s
Corpuscles
 Root Hair Plexus
 Perceive Pressure:
 Pacinian Corpuscle
 Krause’s Corpuscle
(also heat)
 Ruffini Corpuscle
(also cold)
D. Nails
1. Nail = thin, horny plate at end of fingers and toes,
consisting of several layers of dead epithelial cells
(stratum corneum) containing a hard keratin
2. Nail anatomy:
a. Nail body = visible part of nail
b. Nail root = part of nail covered by skin
c. Eponychium or cuticle (upon + nail) = stratum
corneum extending onto nail body
d. Nail bed = nail root and nail body attach to this
e. Nail matrix = proximal portion of nail bed w/o nail
root attached
i. Produces cells that result in nail growth
ii. Nails grow continuously
f. Lunula = whitish, crescent-shape at base of nail
Fingertip & Nail
A.
Burns
1.
Partial-thickness burns – part of stratum basale viable
a. First-degree burns – involves epidermis, red, painful, edema
i. Sunburn, quick exposure to hot/cold
ii. No scarring, heals quickly
b.
c.
Second-degree burns – destruction of epidermis and dermis,
recovery happens from edge of burn
Full-thickness or third-degree burns
i.
ii.
iii.
iv.
Painless b/c nervous tissue destroyed
May appear white, tan, brown, black, or deep cherry red
Scarring with disfiguration, extended healing time
Skin grafts (self, cadavers, pigs, lab-grown?)
Burns
Second-degree
First-degree
(epidermis and dermis,with blistering)
(epidermis only; redness)
Third-degree
(full thickness, destroying
epidermis, dermis, often part of
hypodermis)
Rule of Nines for Adults
 The estimated extend of burns may be calculated
using the rule of nines.
 Totals:
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Anterior & posterior head & neck =
Anterior & posterior upper limbs =
Anterior & posterior trunk =
Perineum =
Anterior & posterior lower limbs =
TOTAL
9%
18% (9% per arm)
36%
1%
36%
100%
Rule of Nines for Adults
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
41/2%
Anterior and posterior head and neck
9%
41/2%
Anterior head
and neck 41/2%
Anterior
trunk
18%
Anterior and
posterior upper
extremities
18%
Anterior upper
extremities 9%
41/2%
41/2%
Anterior and
posterior trunk
36%
Posterior head
and neck 41/2%
Posterior
trunk
18%
Posterior upper
extremities 9%
41/2%
41/2%
Perineum 1%
9%
Anterior lower
extremities 18%
9%
9%
Anterior and
posterior lower
extremities
36%
28
100%
9%
Posterior lower
extremities 18%
Skin Disorders
 Warts - nonmalignant epithelial growth caused by a
virus
 Cold sores (fever blisters)
 small fluid-filled blisters around lips & mouth caused
by a herpes simplex virus
 Acne - inflammation of sebaceous glands
 Impetigo - inflamed lesions caused by staphylococcus
infection
 Decubitus ulcers (bed sores) caused by irritation and
inadequate circulation, especially in areas over bony
projections such as hip bones, heels, etc. (occur most
often in those who are bedridden or confined to a
wheelchair.
 Metastasize
(Metastasis):
Spreading of cancer
 Benign: A noncancerous tumor
 Malignant: A
cancerous tumor
 Carcinoma: Cancer
 Carcinogen: Cancercausing agent
Causes for Skin Cancer
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1.
2.
3.
4.
Overexposure to UV light
Frequent skin infections
Chemical exposure
Physical trauma
Basal Cell Carcinoma
Most common form of skin
cancer
Least deadly
Stratum Germinativum cells
are altered and the boundary
between the dermis and
epidermis is destroyed
Occurs most commonly on sun
exposed areas (face)
Basal Cell Carcinoma (continued)
 Signs and symptoms
 New growth or sore that will not
heal
 Waxy, smooth, red, pale, flat, or
lumpy
 May or may not bleed
 approx. 30% of caucasians will
develop this
 99% cure rate
24-33
Squamous Cell Carcinoma
 Less common than basal cell
carcinoma
 Scaly keratinized elevation
that arises from Stratum
Spinosum
 Found most commonly on
scalp, ears, back of hands,
and lower lip.
 Can metastasize to the
lymph nodes
 Believed to be sun induced
 Good chance of complete
cure
Malignant Melanoma
 From melanocytes, usually
in a pre-existing mole
 Appear on trunk, head,
neck of men
 Appear on arms and legs of
women
 Itches or bleeds
 Metastasizes quickly to
lymph and blood vessels.
 Treatment
 Surgery and biopsy
 Removal of lymph nodes
 Chemotherapy and
radiation therapy
 Immunotherapy
 Survival is helped by early
detection
24-35
Malignant melanoma
 Irregular growths with variety of pigmentation
(brown, gray, black, or blue)
 Occur in all age groups, usually in people who
sunburn easily
 More common in people who get short intense
exposure to sunlight .
 Survival rate is low.
Malignant Melanoma
ABCD’s of Skin Cancer
ABCD Rule
A - Asymmetry
B - Border
irregularity
C - Color
D - Diameter
Skin Cancer
Sqaumous cell carcinoma
Basal cell carcinoma
Melanoma
Reduce your risk of skin cancer:
 Here are some ways to play it safe in the sun:

 Avoid the sun between 10 a.m. and 4 p.m.
 Seek shade: Look for shade, especially in the middle of the day when the sun’s rays
are strongest. Practice the shadow rule and teach it to children. If your shadow is
shorter than you, the sun’s rays are at their strongest.
 Slip on a shirt: Cover up with protective clothing to guard as much skin as possible
when you are out in the sun. Choose comfortable clothes made of tightly woven
fabrics that you cannot see through when held up to a light.
 Slop on sunscreen: Use sunscreen and lip balm with a sun protection factor (SPF) of
30 or higher. Apply a generous amount of sunscreen (about a palmful) and reapply
every 2 hours and after swimming, toweling dry, or sweating. Use sunscreen even on
hazy or overcast days.
 Slap on a hat: Cover your head with a wide-brimmed hat, shading your face, ears, and
neck. If you choose a baseball cap, remember to protect your ears and neck with
sunscreen.
 Wrap on sunglasses: Wear sunglasses with 99% to 100% UV absorption to provide
optimal protection for the eyes and the surrounding skin.
 Follow these practices to protect your skin even on cloudy or overcast days. UV rays
travel through clouds.
 Avoid other sources of UV light. Tanning beds and sun lamps are dangerous. They
also damage your skin in other ways.
 Go to this web address on your Photon Browser and go through
the tutorial and check your skills on identifying skin cancer:
 http://sciencenetlinks.com/interactives/skindeep/interactive/base
.html