Transcript Integumentary System Notes HHAP

Chapter 4: Skin and Body
Membranes
Skin and Body Membranes
 Remember an organ is where 2 or more kinds
of tissues work together to perform some
specific function
 SKIN: epithelial, connective, muscle and
nervous tissue
 Integument: the membranes of the body that
cover, line and protect.
 Includes skin, hair, nails and other membranes
Types of Body Membranes
 Epithelial membranes
 Cutaneous membranes
 Mucous membranes
 Serous membranes
 Connective tissue membranes
 Synovial membranes
Serous Membranes
 Lines body cavities—covers organs in the
thorax and abdomen
 Consists of simple squamous epithelial tissue
and a thin layer of connective tissue
 2 layers of epithelium
 Visceral layer covers the outside of the organ
 Parietal layer lines a portion of the wall of
ventral body cavity
Serous Membranes
Cells of this membrane
secrete a clear fluid
(serous) between the
two layers which helps to
lubricate the organs and
cavities they are in
Serous Membranes
Specific serous membranes
Peritoneum
-Abdominal cavity
Pleura
-Around the lungs
Pericardium
-Around the heart
Mucous Membranes
•Line body cavities that are
open to exterior
•Ex: nasal and oral cavities
•Also in tubes of the
respiratory, digestive,
urinary and reproductive
systems.
•Cells in this membrane
secrete mucus
•Goblet cells make mucus
Cutaneous Membrane
Cutaneous
membrane =
skin
Connective Tissue Membrane
Synovial membrane
Found in the linings of the
joint cavities between the
ends of bones
Secretes a thick colorless
fluid that lubricates the
joint
Integumentary System
 Functions: Protective covering, regulates
body temperature, contains sense organs
and excretes waste.
 Produces Vitamin D in response to UV
radiation. This helps the body absorb
calcium
Skin Layers
Epidermis—outer layer
Stratified squamous
epithelium
Sheds every 30 days
Dermis-inner layer
Thicker than epidermis
Includes connective and
nervous tissue as well as
muscle tissue
Skin Layers
 Subcutaneous (hypodermis)
 Not really considered a layer of skin but
found underneath the dermis is deep to
dermis
 Anchors skin to underlying organs
 Composed mostly of adipose tissue
 Blood vessels for skin are here
Epidermis
 Lacks blood vessels
 Cells at very top are far away from blood
vessels below and eventually die.
 They still provide protection even though
they are not functional cells
 These cells have keratinized
 Keratin is a waterproof protein that forms in
the skin cells as they mature
Epidermis
 The epidermis shields the underlying tissue
from water loss and injury
 Also protects against invasion of microbes
and bacteria
 Melanin is found here.
 Melanin is a dark pigment produced by
melanocytes
 The job of melanin is to absorb light energy
to protect skin from damage.
Epidermis
 If your skin does not
have enough melanin
you are at risk for a
sunburn.
 We all have the same
number of melanocytes
but genetics determine
how much melanin our
cells produce
Epidermis
 Those people with
dark skin have
ancestors that live
near the equator or at
the poles. (both
places have periods
of direct sunlight)
 Color is yellow to
brown to black
Epidermis
•Skin color is also determined by oxygen
content.
•Most of us have a pinkish cast to our
skin because of high oxygen
•Person with oxygen poor blood
because of disease or injury have a
bluish cast to their skin.
•This is called cyanosis
 Stratum Basale; lowest
layer of epidermis
 Mitosis takes place
here
 Stratum corneum; top
layer of epidermis
 All cells here are
dead
Dermis
 Binds epidermis to the subcutaneous layer
 Made of fibrous connective tissue, blood vessels,
nerve fibers, muscle tissue, sebaceous (oil) glands
and sweat glands
 Thickest layer of skin
 Collagen and elastin: fibers that give skin elasticity
(ability to return to original shape) and extensibility
(ability to stretch)
 Lack of collagen and elastin = wrinkles!
 Papillary layer (all dermal papillae) causes
fingerprints
Figure 4.4
SPF-Preventing sun damaged skin
What is SPF?
Is a higher SPF better?
Are tanning beds safe?
Accessory Organs--Hair
Consists of hard keratinized epithelial cells
Hair follicle extends from dermis to surface of
skin. Contains the root
Hair growth—scalp hair grows for about 3 years,
then rests for one
Normal hair loss per day is about 100 hairs
Androgens are necessary for hair growth, but too
much can cause hair loss (male pattern
baldness)
Accessory Organs--Hair
Melanocytes provide pigment
for hair color
Hair color is determined by the
amount of melanin produced
by the melanocytes
arrector pili muscle: attached
to the hair follicle. When it
contracts it causes the hair to
stand on end. Goose bumps!
Accessory Organs—Sebaceous Glands
 Sebaceous glands: associated with hair
follicle, produce oily secretion called sebum.
 Sebum: mixture of fatty material and dead
cells—keeps hair and skin soft to prevent
dry and cracked skin.
 Hair follicle with sebum stuck in them=
blackhead
 Black is oxidized oil—not dirt
 If bacteria present can form pimple or boil
Figure 4.6a
Accessory Organs—Sweat Glands
 Sweat glands:
sudoriferous
glands that
occur in the
skin
 They originate
in the dermis
Accessory Organs—Sweat Glands
 Two types of sweat glands:
 Eccrine: associated with pores, produce sweat in
response to increased body temperature: begin
working right after birth, found all over the body
 Apocrine: associated with hair follicles produce
sweat in response to stress; begin working at puberty.
Contains a higher fat content than normal sweat.
Found mainly in armpits, genital area and around
breasts. Theorized that this sweat contains
pheromones. (thicker and stickier than regular
sweat)
Sweat and Its Function
 Composition
 Mostly water
 Salts and vitamin C
 Some metabolic waste
 Fatty acids and proteins (apocrine only)
 Function
 Helps dissipate excess heat
 Excretes waste products
 Odor is from associated bacteria
Accessory Organs—Nails
 Scale-like modifications of the epidermis
 Heavily
keratinized
 Lack of pigment makes them colorless
 Body is the visible attached portion
 Root of nail embedded in skin
 Cuticle is the proximal nail fold that
projects onto the nail body
Figure 4.9
Clinical Application
 The pink color of the nail bed is clinically significant in that
it can aid in the assessment of perfusion (blood flow) to the
extremities and can be a determinant of oxygenation. If
you pinch one of your fingernails straight down with the
thumb and index finger for 5 seconds you will note that
your nail bed went from a blanched white color back to
pink in a matter of seconds (good profusion). If it takes
longer than 3 seconds for the nail bed to “pink up” then
profusion to the extremities is considered sluggish. This
test is called capillary refill time.
Regulation of body temperature
 As body temp increases blood vessels
dilate and carry hot blood to the surface
to release heat to the atmosphere.
 Sweat glands (eccrine) send sweat to the
surface to cool the body through
evaporation.
Regulation of body temperature
 As body temperature decreases blood
vessels constrict to prevent blood from
flowing to the surface, thereby
conserving heat
 Shivering also occurs; muscle
contractions produce heat through
friction
 Arrector pili muscles contract.
The Integumentary System: Negative Feedback
3 Input:
Information
sent along
afferent
pathway to
Brain
Hypothalamus
2 Change
detected
by receptor
1 Stimulus:
Increased
body
temperature
Body Temperature
4 Output:
Information sent
along efferent
pathway to activate
Blood Vessels
Sweat Glands
Blood vessels dilate
causing heat to radiate
from the body
5
Sweat Glands become
active, cooling through
evaporation.
The Integumentary System: Negative Feedback
3 Input:
Information
sent along
afferent
pathway to
Brain
Hypothalamus
2 Change
detected
by receptor
1 Stimulus:
Decreased
body
temperature
4 Output:
Information sent
along efferent
pathway to activate
Blood Vessels
Sweat Glands
Muscles
Blood vessels constrict
Sweat Glands become
5 less active, muscles
Shiver to generate
heat
Body Temperature
Skin Homeostatic Imbalances
 Macule-discolored spot;
freckle
 Wheal-localized elevation
of the skin that is often
accompanied by itching;
contact dermatitis
Skin Homeostatic Imbalances
 Papule-solid
circumscribed, elevated
area on the skin; pimple
 Nodule- larger papule;
acne vulgaris
Skin Homeostatic Imbalances
 Vesicle-small fluid filled
sac; blister (a bulla is a
larger one; chicken pox)
 Comedo-yellow or black
plug in the skin;
blackhead
Skin Homeostatic Imbalances
 Pustule-small, elevated,
circumscribed lesion of
the skin that is filled with
pus; whitehead
 Erosion (Ulcer)-an eating
or knowing away of tissue;
decubitus ulcer
Skin Homeostatic Imbalances
 Crust-dry, serous, brown,
yellow, red or green
exudation; eczema
 Scale-thin, dry flake of
epithelial cells; psoriasis
Skin Homeostatic Imbalances
 Fissure-crack like sore or
slit that extends through
the epidermis into the
dermis; athlete’s foot
 Cyst-closed sac under the
skin; sebaceous cyst
Skin Homeostatic Imbalances
 Burns
 Tissue damage and cell death caused by
heat, electricity, UV radiation, or
chemicals
 Associated dangers
Dehydration
 Electrolyte imbalance
 Circulatory shock

Rule of Nines
 Way to determine the extent of burns
 Body is divided into 11 areas for quick
estimation
 Each area represents about 9% of total
body surface area
Rule of Nines
Severity of Burns
 First-degree burns
 Only epidermis is damaged
 Skin is red and swollen
 Second-degree burns
 Epidermis and upper dermis are damaged
 Skin is red with blisters
 Third-degree burns
 Destroys entire skin layer
 Burn is gray-white or black
Severity of Burns
Figure 4.11b
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, hands, or feet
Skin Cancer
 Cancer—abnormal cell mass
 Classified two ways
 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
stratum basale
Skin Cancer Types
 Squamous cell carcinoma
 Metastasizes to lymph
nodes if not removed
 Early removal allows a
good chance of cure
 Believed to be suninduced
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 than 6 mm in diameter
Aging Skin
 The amount of
subcutaneous tissue
below the skin decreases,
leading to an intolerance
to cold in the elderly.
 Because of decreased oil
production and declining
numbers of collagen
fibers, the skin becomes
drier and may become
itchy and bothersome.
Aging Skin
 Thinning of the skin makes
it more susceptible to
bruising and other types
of injuries.
 A decrease in elasticity of
the skin, along with the
loss of subcutaneous fat,
allows bags to form under
the eyes and causes jowls
to sag.
Aging Skin
 To delay these
changes, the skin
should be kept
clean and shielded
from the sun, and
a healthy diet with
plenty of fluids
should be
maintained.