Skin - Class 1 Flashcards
another name for the skin
integument
the skin is the _____ to the body
mirror
reflects status of health of the body
-color
-temp
-etc.
what is the first line of defense
the skin
-bacteria
-trauma
-fluid loss
-keeps out microbes
skin is a ______ _____ of the body
major organ
how much of the body does the skin cover
entire body
how much does skin represent –> body mass
8-15%
how thick is skin
varies between 1.5-4mm thick
where is skin the thickest
palm and sole of feet
where is skin thinnest
eyelids
fxns of the skin
acts as a barrier
limits/regulates heat loss
sensation
excretion/absorption
biochemical
acts as a barrier –> fxn
infection/dehydration
thermal and mechanical trauma
limits/regulates heat loss –> fxn
perspiration
children’s regulatory processes are immature –> trouble regulating high/low temps
sensation –> fxns
skin is a major sensory organ
excretion/absorption –> fxn
waste products
biochemical –> fxn
formation of vitamin D
2 types of skin
thin/hairy
thick/hairless
thin/hairy skin
most of the body, more prevalent
general cutaneous fxn
general cutaneous fxn
sensory endings
general protective fxn
hair follicles
thick/hairless skin
extra strength
frictional surface
thick/hairless skin has increased
sweat glands and nerve endings
frictional surface is used for –> thick/hairless
locomotion and manipulation
where is thick/hairless skin located
palms and hand
sole of feet
the layers of the skin are a
intimate association
intimate association
b/w 2 layers w/ a third layer underneath
3 layers of skin
epidermis
dermis
hypodermis (subcutaneous)
epidermis is
keratinized stratified squamous epithelium
what layer is the epidermis
superficial layer
barrier to the outside world
thickness of epidermis
0.06 mm to 0.6 mm
what does the epidermis contain
pigmentation
keratin
merkel cells
langerhans cells
pigmentation –>epidermis
melanocytes
melanin
melanocytes
manufactures melanin
melanin
mature cells
give skin its color
keratin–> epidermis
has different levels of maturity
keratinocytes
merkel cells
mechanoreceptors related to light touch
langerhaans cells
prevent against infection
epidermal appendages are also called
dermal appendages
where are epidermal appendages located
in the dermis –> but are present though epidermis
what is contained in the epidermal appendages
hair follicles/shaft
sebaceous glands
sudoriferous glands
nails
arrector pilli muscles
what do we have through appendages
reproduction of epithelial cells
what does the presence of these appendages allow
healing w/o a skin graft
epidermis is a ________ ______ of _______ ________
progressive layer of dying cells
5 layers of the epidermis
corneum
lucidum
granulosum
spinosum
basale
basil layer (stratum basale)
deepest layer
responsible for the manufacture of keratinocytes
keratinocytes
makes keratin
where are the largest amount of melanocytes found
stratum basale
esp. in lighter skin
melanocytes + keratinocytes =
epidermal unit
epidermal unit
melanocytes associated with neighboring keratinocytes
dendrites from melanocytes provide pigmentation to keratinocytes
fxns of the stratum basale
attaches dermis and epidermis
produces cells
stratum spinosum
several layers of more mature keratin filaments
how far is the stratum spinosum from basale
8-10 cell layers up
fxn of stratum spinosum
allow keratinocytes to mature
stratum granulosum
3-5 layers of flatted keratinocytes
stratum lucidum
few layers of flattened dead cells
appears clear
thicker in parts of the skin that are thicker
stratum corneum
“horny” layer
superficial layer of the epidermis
primary barrier layer
the stratum corneum is entirely a
dead layer of keratinocytes
20-30 cells thick
the stratum corneum will have equal ______ regardless of skin color
thickness
what is different b/w skin colors –> corneum
number of layers
darker skin –> corneum
same thickness
more cohesive or compressed with more layers
more protection against UV rays
dermal-epidermal jxn prevents
shearing of layers
decreased shear resistance
dermal epidermal jxn consists of
Rete Ridges
Dermal Papillae
Rete Ridges
pegs
epithelial extensions that project into the underlying dermis
dermal papillae
dermal extensions extending up to meet rete ridges
what creates the dermal papillae
interdigitating of rete ridges and dermal papillae
fxn of dermal papillae
resist shear and tearing of skin
allows nutrients from dermis to feed the epidermis
increased area b/w epidermis and dermis for nutrition
what happens to the dermal-epidermal jxn with aging
flattens –> results in skin tears
skin is not as strong or cohesive
dermis
moderately dense, irregular connective tissue layer
how thick is the dermis
2-4mm
what does the dermis contain
high amounts of collagen
blood vessels, lymph
nerves
hair follicles
sebaceous and sweat glands (epidermal appendages)
2 layers of the dermis
papillary layer
reticular layer
papillary layer
superficial layer
connection to epidermis
contains blood vessels that supply nutrients and control temp of epidermis
reticular layer
thicker
deep layer
provides elasticity and strength
what does the reticular layer contain
structural support
contains type 1 collagen
vasculature supply
nerve endings, glands
hair follicles and elastic fibers
fxn of the dermis
mechanical anchor
metabolic support
trophic protection
sensory organs
mechanical anchor –> dermis
skin to underlying tissue
fibroblasts are common cells in the level of the dermis
fibroblasts
make collagen
metabolic support –> dermis
through blood supply to epidermis and through dermis
trophic protection –> dermis
mast cells (immune response)
macrophages (WBCs)
sensory organ –> dermis
sensory nerve endings
schwann cells (glial cells) located
pacinian corpuscles
pacinian corpuscles –> sensory organ –> dermis
mechanoreceptors that sense pressure and high frequency vibration
senses stretch
hypodermis/subcutaneous layer
highly vascular layer
composed of fat cells and connective tissue
not a true layer
what does the subcutaneous layer contain
adipose tissue
fascia
adipose tissue
fat (adipocyte)
manufactures fat cells
fascia
connective tissue
allows movement of skin over body
fxn of subcutaneous layer
insulates and cushions
what happens to the subcutaneous layer as we age
hypodermis decreases in size –> skin begins to sag
what is adipose tissue NOT
not a passive site for energy storage
fat is the largest
endocrine organ in the body
fat is classified as
an endocrine organ
an immune organ
what does fat do
releases hormones
affect MS system, pancreas, heart and CNS
adipocytes are
fat cells
in normal weight individuals, fat assists in regulating
BP
appetite
blood coagulation
affects health of muscles
decreases risk of CVD
with obesity –> fat cells
increase in size and number
what does enlarging of fat cells result in
changes in physiology
changes in physiology –> obesity & fat cells
hormones become abnormal
–> can enhance or cause metabolic disorders
what do metabolic disorders lead to
chronic inflammation in the body linked to
-insulin resistance
—-> type 2 diabetes
excessive body fat leads to
chronic state of inflammation in the body
fat can be
subcutaneous or visceral
subcutaneous fat
fatty layer
contains a large vascular plexus
provides padding to bone
energy release
energy release –> subcutaneous fat
stores fat to be released when needed
visceral fat
surround internal organs
RF for diabetes and heart dz/stroke
waist to hip ration
describes deposition pattern for fat cells
waist is smaller than hips
low risk for diabetes and CVD
waist is larger than hips
high risk for diabetes and CVD
more visceral fat
ex of hormone/protein released by adipocytes
leptin
with normal weight –> leptin
provides appetite control
appetite suppressant in CNS –> signals the brain when you are full
increases energy consumption
with obesity –> leptin
chronically elevated levels
CNS becomes leptin resistant
opposite rxn –> no appetite control
