Skin Flashcards
Functions of skin (5):
Protection (physical and immune), containment (prev dehydration), thermal regulation, sensation, and synthesis + storage
–Keratinized epithelium
* Tough, protective superficial layer
* Regenerative and pigmented basal layer
* No blood vessels or lymphatics (avascular)
* Less than 1 mm, except for soles of feet
Epidermis
(1-2 mm on average)
* Provide skin tone and account for strength and toughness of skin
- Most nerve terminals in here, a few penetrate
the epidermis
Dermis
Dermis: Supplied by arteries that enter its deep
surface to form a _____ of
anastomosing arteries
cutaneous plexus
Which layer of epidermis is regenerative and pigmented?
Basal Layer
- Most nerve endings (sensitive to touch,
irritation/pain, temperature) found here
dermis
Dermis: Dense layer of
interlacing ____ and ___ fibers
collagen and elastic
____ : accidental cuts and skin tears
Lacerations
Superficial Lacerations– penetrate the _____ and
sometimes ____, they bleed but
don’t interrupt the continuity of the dermis
epidermis. superficial layer of dermis.
Deep Lacerations– penetrate the deep layer of ______,
extending into the subcutaneous layer or beyond,
they gape and require approximation of the cut edge
of the dermis (by suturing) to minimize scarring
dermis
linear clefts in the skin that indicate the direction
of orientation of the underlying collagen fibers
Tension lines (cleavage lines, langer lines)
Tension Lines: Tend to spiral ____ in the limbs and run _____in the neck and trunk
longitudinally; transversely
Tension Lines: At joints, the lines are ____ to the transverse creases that
appear when the limbs are flexed
parallel
Cleavage lines are also known as tension lines or
langer lines
Incision or cut parallel to tension line results in
faster healing, less scar tissue
slower healing and increase in scar issue occurs when an incision is cut ____ to the tension line
oblique or perpendicular
a pilosebaceous unit includes:
hair follicles, arrector muscles of hairs, and sebaceous glands
Where will you NOT find hair follices:
(hair follicles are generally slanted to one side)
palms of hands,
soles of feet, lips, and urogenital orifices
Erects or raises hairs, causing goose bumps
- Activated under conditions of stress by
sympathetic nervous system
Arrector muscles of hairs (musculi arrector pili)
Sebaceous glands secrete what substance? What is the function of that substance?
sebum – an oily substance that protects
the skin from drying out
–Lie on the side the hair is directed towards as it
emerges from the skin (side with arrector muscle)
Sebaceous Glands
–Hormonal target and play a prominent role in acne
vulgaris from the formation of sebum plugs
Sebaceous Glands
Contraction of the ____ causes the
hairs to stand up straighter, thereby compressing
the sebaceous glands and helping them secrete
their oily product (sebum) onto the skin surface.
arrector muscles (smooth muscle)
what causes compression of the sebaceous glands, helping them secrete
their oily product (sebum) onto the skin surface.
Contraction of the arrector muscles causes the hair to stand up
Evaporation of sweat from the skin provides a ____
mechanism
cooling
Sweat glands are activated by ________
sympathetic nervous system
_____ Sweat glands: In axilla, around nipples, in pubic area
(labia majora, scrotum), in anal area.
Start to function during puberty
Apocrine
_____ Sweat glands: found everywhere except vermillion
border of lips, external ear
canal, nail beds, glans penis,
clitoris, and labia minora
Eccrine
____ Sweat glands: Secrete Mostly water with some ion
and nitrogenous waste
excretion
Eccrine
_____ sweat Glands: secrete Viscous, protein and lipid-rich product
that is initially odorless but can develop
odor after exposure to bacteria. Also
stimulated by adrenaline (NE)
aprocrine
Sweat glands playing a major role in thermoregulation
eccrine sweat glands
sweat glands serving as scent glands, minor role in thermoregulation
apocrine sweat glands
Large, branched sweat glands that release into hair follicles
Apocrine sweat glands
Sharp demarcation between the lip
and the adjacent normal skin
Vermillion Border of Lip
Vermillion Border of Lip: Represents change in the ____
from highly keratinized external skin to
less keratinized internal skin
epidermis
Epidermis is ____ on lip, so the blood
vessels are closer to the surface giving the
lip a reddish-pink to brown color
(depending on skin tone)
thinner
T/F–Vermillion Border of Lip: No sebaceous glands, sweat glands, or
facial hair
True
Superficial Capillary Beds–Small arteries (arterioles) within the
dermis can:
* ____ to fill superficial capillary beds to
radiate heat (skin appears red)
Dilate
Superficial Capillary Beds–Small arteries (arterioles) within the
dermis can:
____ to radiate heat
dilate
(skin appears red)
Superficial Capillary Beds–Small arteries (arterioles) within the
dermis can: constrict to minimize surface heat loss. How does this affect appearance?
skin, especially lips and fingertips, appears blue
Modified Apocrine sweat glands that produce milk to
nourish offspring
Mammary Glands
Hair: In cross-section, round hairs will grow
____ and oval hairs will be
straighter. curly.
Hair: Color is dependent on amount of ____ in
hardened hair cells
melanin
Finger and toenails
* Function: protect digits and contribute to
____ sensation
tactile
____ is the hard, keratinized structure
made from onychocytes, organized in a
lamellar pattern
Nail plate
Nail plate is made from _____, organized in a
lamellar pattern
onychocytes
(These cells are a type of epithelial cell that has undergone keratinization, a process where they produce large amounts of keratin, a tough, fibrous protein that gives nails their strength and resilience)
Onychocytes are the specialized keratinocytes
Subcutaneous Tissue (Hypodermis) also called ___
superficial fascia
Located between the dermis (overlying
skin) and deep fascia
Subcutaneous Tissue (Hypodermis)
Subcutaneous Tissue (Hypodermis)– composed mostly of ____ CT and stored fat
Loose
T/F: Subcutaneous Tissue contains sweat glands, superficial
blood vessels, lymphatic vessels, and
cutaneous nerves
True
____ branches from cutaneous
nerves and superficial vessels reach the
skin (specifically dermis)
Terminal
T/F: Cutaneous nerves are both sensory
and motor
True
Vessels with smooth muscle in walls, arrector
muscles, and sweat glands all require ___
innervation to function
motor
Motor fibers are part of the ____ nervous
system
sympathetic
The thickness of subcutaneous tissue varies
greatly, depending on ___
the person’s nutritional
state
Distribution of ____ tissues varies
considerably in different sites in the same
individual
subcutaneous
T/F: Distribution of subcutaneous tissue and fat
varies between the sexes
True (females–breasts and thighs, men–lower abdominal wall)
Participates in thermoregulation
* Insulation to retain body heat in core
* Padding to protect skin from compression by bony prominences (e.g. in buttocks,
bottom of foot)
* Store energy in form of adipose tissue
subcutaneous tissue (hypodermis)
subcutaneous tissue stores energy in the form of:
adipose tissue
____ determine the mobility of the skin
over deep structures
skin ligaments
Skin Ligaments: Numerous small fibrous bands extend
through the ___ tissue and
attach the deep surface of the dermis
to the underlying deep fascia
subcutaneous
Longer and sparse skin ligaments = ___ skin mobility
more
Another word for “Deep Fascia”
epimysium
Dense, organized connective tissue
layer, devoid of fat, that covers
most of the body parallel to (deep
to) the skin and subcutaneous
tissue
Deep fascia
Deep fascia is Dense, organized connective tissue
layer, devoid of ___
fat
Extensions from its internal surface
invest deeper structures, such an
individual muscles and neurovascular
bundles, as investing fascia
Deep fascia
Deep fascia: Thickness varies widely and, in the ____,
distinct layers of deep fascia are absent
face
Groups of muscles with similar
functions (usually sharing nerve
supply) are in fascial compartments
that are separated by thick sheets of
deep fascia, called ____
intermuscular
septa
Groups of muscles with similar
functions (usually sharing nerve
supply) are in _____
fascial compartments
Burns: caused by thermal trauma, ultraviolet or
ionizing radiation, or chemical agents. Burns are
classified, in increasing order of severity, based on
the ___ of skin injury and the need for surgical
intervention.
depth
intermuscular septa extend from surrounding fascial sleeve to attach to ____
bones
(these compartments can contain or spread an infection of tumor)
damage limited to
epidermis
superficial burn
epidermis and superficial
dermis are damaged with blistering or loss of those
layers
* Nerve endings are damaged, making this variety the most painful
* Sweat glands and hair follicles are typically not entirely damaged
Partial-thickness burn
entire thickness of skin is
damaged and often the subcutaneous tissue
* Skin grafting is normally needed for healing
* Burned area is numb since sensory endings are destroyed
full-thickness burn
_______ burn – damage extends through entire
thickness of skin into underlying fascia, muscles, or
bone
Fourth-degree burn
Burns are considered severe if they cover
__or more of the total body surface area
(excluding superficial burns)
20%
Burns can be complicated by trauma or inhalation
injury, or being caused by chemicals or ___
high-
voltage electricity
Burns–Risk of death increases if:
* Older than 60 years old
* Partial-thickness or full-thickness burns of over
40% of body surface area
* Presence of ____ injury
inhalation injury
A chronic, noncontagious, auto-immune skin
condition that causes a rash with itchy, scaly
patches, most commonly on the knees, elbows,
trunk, and scalp
Psoriasis
Segmented Spinal Nerves: 31 pairs of spinal nerves, each associated
with a pair of ___ (8 cervical, 12
thoracic, 5 lumbar, 5 sacral, 1 coccygeal)
somites
___ dermamyotomes give rise to all the
intrinsic (deep) back muscles, as well as
dermis that covers them.
Epaxial
____ ramus of spinal nerve supplies
motor and sensory innervation to epaxial
Posterior/dorsal
____ dermamyotomes give rise to all the
other skeletal muscles and dermis below the
neck, including the limbs
Hypaxial
= areas of skin mainly supplied by a single
spinal nerve
Dermatomes
Dermatomes: Each of these nerves relays ___
from a particular region of the skin to the brain
sensation (including pain)
A pinched spinal nerve can cause a ___ loss of
sensation (would also be accompanied by a motor deficit)
dermatomal
Majority of anterior rami merge
with one or more adjacent anterior
rami to form the major ____
somatic
nerve plexuses
Therefore, most _____ nerves
arising from the plexus contain fibers
from multiple spinal nerves
peripheral
Named nerves may be comprised of
more than one spinal nerve and
thus will span more than one
____
dermatome
T/F: Skin on the anterior and posterior trunk
have dermatome and peripheral nerve
distribution that often match each other
True (spinal nerves do not join a plexus)
T/F: Dermatomes and peripheral cutaneous
nerve distribution match each
other in the limbs and neck
False–do not match
Individual peripheral nerves are often
composed of multiple nerve roots levels,
so the ___ of a peripheral
sensory nerve crosses over different
dermatomes
receptive field
T/F: Although segmental nerves merge and
lose their identify when plexus formation
results in multisegmental peripheral
nerves, the segmental (dermatomal)
pattern of nerve fiber distribution
remains
True
