INTEGUMENTARY
SYSTEM
Body
Membranes,
Layers, and
Structure of
the skin!
BODY MEMBRANES
 Covers surfaces, line body cavities, and form protective sheets
around organs
 Two major groups:
 Epithelial Membranes
 Cutaneous Membranes
 Generally the skin or integumentary system
 Mucous Membranes
 Serous Membranes
 Connective Tissue Membranes
 Synovial Membranes
EPITHELIAL
MEMBRANES
•
•
•
Cutaneous
Membranes
Mucous
Membranes
Serous
Membranes
EPITHELIAL MEMBRANE OVERVIEW
 The “epithelial” membranes is a
misleading/inaccurate title because they do
contain an epithelial sheet (always present with
the underlying layer of connective tissue)
 SIDE NOTE: these membranes are actually simple organs
CUTANEOUS MEMBRANE
 It is your skin
 Its superficial epidermis is composed of a keratinizing
stratified squamous epithelium
 The underlying dermis is mostly dense (fibrous) connective
tissue
 Exposed to air and is a dr y membrane
 Unlike any other membranes
MUCOUS MEMBRANES
 Composed of epithelium (type varies on the site) resting on a
loose connective tissue membrane called lamina propria
 Lines all cavities that open to the exterior
 Think of HOLLOW organs





Respiratory
Digestive
Urinary
Reproductive
etc.
 The term mucosa refers only to the location of the
membranes not the cellular makeup
 They are wet or moist membranes almost continuously bathed
in secretions
SEROUS MEMBRANES
 Composed of a layer of simple squamous epithelium resting on a think
layer of areolar connective tissue
 Areolar connective tissue holds organs in place and attaches epithelial tissue to
other underlying tissues
 Line the body cavities that are CLOSED to the exterior
 Except for the dorsal body cavity and joint cavities
 Serous membranes occur in pair s
 Parietal later lines a specific portion of the all of the ventral body cavity
 Folds itself into the visceral layer which covers the outside of the organs in that
cavity
 Think about pushing your fist into a limp balloon
 The part of the balloon touching your fist is the visceral serosa
 The outer wall of the balloon is the parietal serosa
 The specific names of the serous membranes depend on the location
 Peritoneum: serosa lining the abdominal cavity
 Serous membranes in the thorax isolate the lungs and heart from one another
 Pleura isolate the lungs
 Pericardium isolate the heart
CONNECTIVE TISSUE
MEMBRANES
Synovial
mebranes
SYNOVIAL MEMBRANES
 Composed of soft areolar connective tissue and contain
no epithelial cells at all
 Line fibrous capsules surrounding joints where they
provide smooth surface and secrete a lubricating fluid
 Contain small sacs of connective tissue called bursae
and the tube-like tendon sheaths
INTEGUMENTARY
SYSTEM
Basic
Functions and
Structure
OUR SKIN
 Skin, or cutaneous membrane, is your waterproof, repairable,
stretchable, washable, permanent press, easy -to-care for coat.
 The skin and its derivatives (sweat glands, oil glands, hairs,
and nails) serve a number of functions, mostly protective.
 All of these are collectively known as the Integumentary
System.
FUNCTIONS
 Protects
 Against mechanical damage
 bumps and cuts
 Against chemical damage
 Acids and Bases
 Against thermal damage
 Heat and Cold
 Against UV radiation
 sunlight
 Against bacteria
 Insulates
 Cushions
FUNCTIONS AND ADAPTATIONS
 The uppermost layer of the skin is full of keratin and
cornified in order to prevent water loss from the body
surface
 Regulates heat loss from body surface with a rich capillary
network and sweat glands
 Acts as a mini-excretory system
 Getting rid of urea, salts, and water through sweat
 Manufactures proteins important to immunity and
synthesizes vitamin D
 Cutaneous sensory receptors (part of the nervous system)
located in the skin help to feel touch, pressure,
temperature, and pain
STRUCTURE OF THE SKIN
all the
different
layers
EPIDERMIS & DERMIS
 The skin is composed of two kinds of tissue
 The outer EPIDERMIS
 Made up of stratified squamous epithelium that is capable of kertinizing
(becoming hard and tough)
 The underlying DERMIS
 Made up of dense connective tissue
The epidermis and the dermis are firmly connected, however,
when burned or friction may cause them to separate = BLISTER
INSIDE THE DERMIS
 Deep in the dermis is the SUBCUTANEOUS TISSUE known as
the HYPODERMIS which is essentially adipose tissue
 This is not considered part of the actual skin but it does anchor the
skin to the underlying organs
 It serves as a ‘shock-absorber’ and insulates the deeper tissues from
extreme temperature changes outside of the body
 Responsible for “womanly curves”
EPIDERMIS
The 5 strata
EPIDERMIS
 The epidermis is avascular
 (ex: shaving)
 Mostly keratin cells
 Deepest cell layer is the
stratum basale 5th – constant
cell division (millions of new
cells a day) cells are pushed
upward (outward) toward the
stratum spinosum 4th then the
stratum granulosum 3rd then
the stratum lucidium 2nd and
finally the stratum corneum 1st
PG 100
 You are expected to read and understand
page 100 in your book over the layers of
epidermis and MELANIN/Melanocytes
 Know why moles are freckles appear on the
skin
 Know the damage that occurs from over
exposure of the sun
DERMIS
Strong,
stretchy
envelope that
holds us
together
DERMIS STRUCTURE
 The dense (fibrous) connective tissue making
up the dermis consists of two major regions
 Papillary
 Reticular
 Varies in thickness depending on the area
 Thick on the palms of the hands and soles of the
feet & thin on the eyelids
PAPILLARY LAYER
 Upper dermal region
 Uneven and has finger-like projections from its superior
surface, called dermal papillae
 Contain capillary loops that provide nutrients to epidermis
 House pain receptors and touch receptors (called Meissener’s
corpuscles)
 Palms of hands and soles of feet, the papillae are arranged in
patterns to increase friction and gripping
RETICULAR LAYER
 Deepest skin layer
 Contains blood vessels, sweat, and oil glands and deepest
pressure receptors called PACINIAN CORPUSCLES
 Pacinian corpuscles act to prevent bacteria that have managed to get
through the epidermis from penetrating further into the body
DERMIS OVERVIEW
 Collagen and elastic fibers are found throughout the dermis
 As we age the number of collagen and elastic fibers decrease,
and the subcutaneous layers tissue looses fat = WRINKLES
PHYSIOLOGY
NORMAL BODY TEMPERATURE
Core Temperature
and Normal
Temperature
 The temperature of the
deep tissues of the
body – the “core” of the
body remains very
constant within 1
degree Fahrenheit day
in and day out
 With the exception of a
febrile illness
**Febrile illness = Fever
The skin temperature
rises and falls with
the temperature of
the surroundings.
 The skin temperature is
the important
temperature when we
refer to the skin’s
ability to “lose heat to
the surroundings.”
NORMAL CORE TEMPERATURE
 Average core temperature is from 98 -98.7 (F) when measured
orally (and typically 1 degree higher when measured rectally)
 Body temperature rises during exercise and varies with
surroundings because temperature regulatory mechanisms
are not perfect.
 Intense exercise can raise up to 101-104
 Cold surroundings can lower to 96
HOW IS BODY TEMPERATURE
CONTROLLED?
Body temperature is controlled by balancing
heat production against heat loss
HEAT PRODUCTION
 Heat production is a principal by -product of metabolism
 The rate of heat production = metabolic rate of the body
HEAT LOSS
 Most of the heat produced in the body is generated in the
deep organs, especially in the liver, brain, heart and skeletal
muscles during exercise.
 The heat is transferred from the deeper organs and tissues to
the skin, where it is lost to the air and other surroundings.
 Therefore, the rate at which heat is lost is determined almost
entirely by two factors.
 1) how rapidly heat can be conducted from where it is produced in
the body core to the skin
 2) how rapidly heat can then be transferred from the skin to the
surroundings
INSULATOR SYSTEM OF THE BODY
 The skin, the subcutaneous tissues, and especially the fat of
the subcutaneous tissues act together as a heat insulator for
the body
 The fat is important because it conducts heat only 1/3 as
readily as other tissues.
BLOOD FLOW TO THE SKIN FROM THE
BODY CORE PROVIDES HEAT TRANSFER
 Blood vessels are distributed profusely beneath the skin
 Especially important is a continuous venous plexus that is supplied
by inflow of blood from the skin capillaries