Transcript Ch 4 Integumentary

Chapter 4
Skin &
Body Membranes
Integumentary System
Skin (cutaneous membrane)
Skin derivatives
Skin Functions
-Sweat glands
-Oil glands
1. Protects deeper tissues
-Hairs
from:
-Nails
wMechanical damage
wChemical damage
wBacterial damage
wThermal damage
wUltraviolet radiation
wDesiccation
2. Aids in heat regulation
3. Aids in excretion of uric acid
4. Synthesizes vitamin D
Skin Structure
The skin is composed of three layers:
1. Epidermis- (outer layer) composed of
stratified squamous epithelium which is
keratinized
2. Dermis- (middle layer) composed of dense
irregular connective tissue
-accessory organs: hair follicles, eccrine and
apocrine glands (sweat glands), sebaceous
glands (oil glands), blood vessels, nerve
endings, arrector pili muscles, and capillary
beds.
3. Hypodermis – (lower layer or
subcutaneous layer) composed of adipose tissue
contains arteries, veins, and large nerves
Layer of Epidermis
Stratum basale
wCells undergoing mitosis
wLies next to dermis
wcontains cells called melanocytes
Stratum spinosum
Stratum granulosum
Stratum lucidum
wOccurs only in thick skin (soles of feet
and palms of hands)
Stratum corneum
wShingle-like dead cells
Identify the layers of the thick skin tissue sample.
Stratum corneum
Stratum lucidum
Stratum granulosum
Stratum spinosum
Stratum basale
X - RayNQ
Normal Skin Color Determinants
Melanin
Yellow, brown or black pigments
Carotene
Orange-yellow pigment from some vegetables
Hemoglobin
Red coloring from blood cells in dermis capillaries
Oxygen content determines the extent of red
coloring
Melanin
Pigment produced by melanocytes
Melanocytes are mostly in the stratum basale
Amount of melanin produced depends upon
genetics and exposure to sunlight-"tanning effect"
Put the layers of the skin in order from outer most to inner most.
stratum granulosum
stratum basale
hypodermis
epidermis
stratum lucidum
dermis
stratum spinosum
stratum corneum
Quanecia's Integument Rythym
Dermis
Two layers
1. Papillary layer
Projections called dermal papillae
(responsible for fingerprints)
Pain receptors
Capillary loops
2. Reticular layer
Blood vessels
Glands
Nerve receptors
Appendages of the Skin
Sebaceous glands
§Produce oil
Lubricant for skin
Kills bacteria
§Ducts that empty into hair
follicles
§Glands are activated at
puberty
Sweat glands: produce sweat
Two types:
a. Eccrine: produce watery sweat,
found all over body
- empty out on the epidermis
surface
b. Apocrine: produce sweat, fatty
substances, and protein
- Located in the axillary and pubic
regions
- Become active during puberty
- body odor due to bacteria
- empty into hair follicles.
Modified apocrine glands:
Ceruminous glands: ear, produce
Function
cerumen or ear wax
Helps dissipate excess heat
Mammary glands: breasts, produce
Excretes waste products
and secrete milk
Acidic nature inhibits bacteria growth
Appendages of the Skin
Hair
-Produced by hair bulb
-Hard dead keratinized epithelial cells
-Melanocytes provide pigment for hair color
Hair Anatomy
Central medulla
Cortex surrounds medulla
Cuticle on outside of cortex
Associated Hair Structures
Hair follicle
Arrector pilli
Smooth muscle
Sebaceous gland
Sudoriforous gland
Appendages of the Skin
Nails
Scale-like modifications of the epidermis
§Heavily keratinized
§Stratum basale beneath the nail bed
is responsible for growth
Lack of pigment makes them colorless
Nail Structures
Free edge
Body
Root of nail
Eponychium – proximal nail fold
that projects onto the nail body
Label the fingers!
Cuticle Nail root Lanula Cuticle Nail matrix
Body of nail Free edge Nail bed Body of nail
Appendages of the Skin
Nerve receptors: The skin has receptors for
pressure (Pacinian and Meissner’s
corpuscles), pain, and temperature.
Meissner’s corpuscles are located just below
the surface of the epidermis and are sensitive
to light pressure or touch, these are
associated with “tickling sensations”.
Pacinian Corpuscles are located deep in the
dermis and are associated with strong touch
and pressure.
Root hair plexus are associated
with each hair follicle and is
responsible for the pain when your
hair is pulled.
Free nerve endings are scattered
throughout the dermis and are
specialized for the reception of
heat, cold, or pain.
Temperature Regulation
• Your skin acts similar to a
radiator on a car to
disseminate heat that is
produced by cellular activity
in your body and muscular
contraction.
• This process is under the
control of the hypothalamus
in the brain.
• Negative feedback
mechanism
Temperature Regulation
• body temperature goes above the
set homeostatic value
• the blood vessels in the dermis dilate and
increase blood supply to the capillary
beds located there
• eccrine glands begin to secrete sweat
which moves to the surface of your
epidermis
• heat is transferred from the blood in your
capillaries, through the dermis and
epidermis, to the surface of the epidermis
and is absorbed by the water in the sweat
and vaporizes or evaporates it
• The blood has now lost heat and is at a
lower temperature and returns to the
inner body away form the surface to cool
the inner body structures
Temperature Regulation
• When the body’s temperature falls below the set
homeostatic value
• The arterioles constrict, forcing blood toward the interior organs
• The pili arrector muscles contract, generating heat, and raising the
hair trapping an insulating layer of air around the skin
Label the diagram!
Eccrine sweat gland
Eccrine sweat gland
Hair root Dermis
arrector pili muscle
Root hair plexus
Pacinian corpuscle
Adipose tissue
Sebaceous gland
Free nerve ending
Hypodermis vein
Meissner's corpuscle
Epidermis Sweat pore
Hair follicle
artery
Hair shaft
A, D
A, D
E
H
B
A
H
B
G
Melanin
Keratin
T
Corneum
Shaft
Dermis
Cortex
Medulla
Cuticle
Cortex
Medulla
Cuticle
hair bulb
hypodermis
sweat gland dermal papillae
dermis nerves epidermis
arrector pili hair follicle
stratum corneum
hair shaft
adipose
sebaceous gland
Skin Homeostatic Imbalances
Infections
1. Athletes foot
Fungal infection
2. Boils and carbuncles
Bacterial infection
3. Cold sores
Viral
Infections and allergies
4. Contact dermatitis
Exposures cause allergic reaction
5. Impetigo
Bacterial infection
6. Psoriasis
Cause is unknown
Triggered by trauma, infection, stress
Diseases and Disorders of the Skin
Immunological
• Acne vulgaris: Due to
formation of sebum plugs
(white heads or black heads)
which block the sebaceous
gland and often trap bacteria
within the gland.
– Can become inflamed which can
lead to the secondary infections
of sweat gland or hair follicle
forming pustules or pimples
Diseases and Disorders of the Skin
Immunological
• Chicken pox: due to a viral
infection (Herpes zoster) of
the skin which affects the
nerve ending
– results in the formation of
blisters that itch
Diseases and Disorders of the Skin
Immunological
• Tinea: Ring worm, Athlete’s
foot, and Jock itch are all the
result of a fungal infection of
the skin.
– results in scaling, erythema
(reddening), and occasional
cracking of the skin that
burns or itches
Diseases and Disorders of the Skin
Immunological
• Warts: due to infection by the
human papilloma virus.
– causes abnormal growth of the
epidermal layer
– Normally warts are benign but
some forms can transform and
become malignant (cervical
cancer)
– transmitted by direct contact from
one person to another
Diseases and Disorders of the Skin
Immunological
• Impetigo: caused by an
infection of the epidermis by
Staphlococcus or
Streptococcus bacteria
– results in erythema, formation
of weeping blisters, that form a
yellow crusting on their surface
– highly contagious and common
in children
Diseases and Disorders of the Skin
Immunological
• Contact dermatitis: due to an
allergic reaction with
materials which the skin has
made contact
– characterized by erythema,
edema, blistering and scaling of
the skin
– Itching is usually associated
with the area affected
– Poison Ivy is an example of this
disorder
Diseases and Disorders of the Skin
Immunological
• MRSA infection is caused by
Staphylococcus aureus bacteria
— often called "staph." MRSA
stands for methicillin-resistant
Staphylococcus aureus
(resistant to antibiotics)
– can be fatal.
– Most MRSA infections occur in
hospitals or nursing homes and
dialysis centers.
– community-associated MRSA:
responsible for serious skin and
soft tissue infections and for a
serious form of pneumonia.
Matching
1. Characterized by dry cracked skin with
burning and itching, usually between the
toes.
2. Caused by the human papillomavirus.
3. A red itchy rash sometimes caused by
poison ivy.
4. A bacterial infection that usually occurs in
children, characterized by crusty or oozing
blisters.
5. A serious staph infection.
Dermatitis
MRSA
Tinea
Impetigo
Warts
Athlete's foot
Dermatitis
Boil
Impetigo
Chicken pox
Herpes
Warts
Acne
Psoriasis
MRSA (boil)
Skin Homeostatic Imbalances
Burns
Tissue damage and cell death caused by heat, electricity, UV
radiation, or chemicals
Associated dangers
Dehydration & infection
Electrolyte imbalance
Circulatory shock
Rule of Nines
Determines the extent of burns
Body is divided into 11 areas-for quick estimation
Each area represents about 9%
Severity of Burns
• 1st Degree burns:
– epidermis only
– result in redness and swelling (edema)
– Usually no scarring of tissue
• 2nd Degree burns:
– epidermis and dermis, some damage to
accessory organs
– blistering but usually little scarring.
• 3rd Degree burns:
– epidermis, dermis, and hypodermis
– destruction of dermal accessory organs, burn
is raw or blackened in appearance
– Severe scarring occurs, long healing period,
usually involving skin grafting
Critical Burns
Burns are considered critical if:
Over 25% of body has second degree burns
Over 10% of the body has third degree burns
There are third degree burns of the face, or feet
What degree of burn is shown in the pictures?
Skin Cancer
Cancer – abnormal cell mass
Two types
Benign
Does not spread (encapsulated)
Malignant
Metastasized (moves) to other parts of the body
Skin cancer is the most common type of cancer
Skin Cancer Types
Basal cell carcinoma
 Least malignant
 Most common type
 Arises from statum basale
Squamous cell carcinoma
 Metastasizes to lymph nodes
 Early removal allows a good
chance of cure
Skin Cancer Types
Malignant melanoma
Most deadly of skin cancers
Cancer of melanocytes
Metastasizes rapidly to lymph and blood vessels
Detection uses ABCD rule
ABCD Rule
A = Asymmetry
Two sides of pigmented mole do not match
B = Border irregularity
Borders of mole are not smooth
C = Color
Different colors in pigmented area
D = Diameter
Spot is larger then 6 mm in diameter