The integumentary system functions as a protective barrier and plays key roles in sensory perception, temperature regulation, metabolism, and secretion. It is made up of multiple tissues including epithelial and connective tissues, and consists of three main layers: the epidermis, dermis, and hypodermis. Disorders affecting the skin can include infections, inflammatory conditions, and various types of skin cancer, with treatments varying based on the specific condition.

1. INTEGUMENTARY
SYSTEM

3. ⦿ The term integumentary comes from the
latin word integumentum which means
“covering”
⦿ The integumentary System has been called
both a system, because it covers the body,
and an organ, because it contains several
different types of tissues and organs that
work together to perform important functions
⦿ Most anatomy courses refer to it as a
system because it has organs and other
parts working together to perform specific
functions

4. FUNCTIONS
:
⦿ Protection
⚫Barrier to UV rays, through keratin and
melanin (pigment produced by specialized
cells called melanocytes)
⚫Prevents invasion of pathogens (keratin)
⚫ water barrier through oils and keratin to
prevent absorption and
evaporation
⦿ Sensory perception
⚫Nerves in skin respond to pain, pressure,
temperature, vibration and touch through
merkel cells located in stratum basale. These
cells relay information re: touch to the brain

5. FUNCTION, cont’d
⦿ Temperature regulation
⚫Vessels dilate (get larger) so heat escapes
through the skin as sweat
⚫Vessels constrict (get smaller) so heat can
be retained when needed
⦿ Metabolic regulation
⚫ Sunlight converts cholesterol molecules to
vitamin D, which is essential for bone health. We
need 10-15 min of sunlight daily to make Vit D

6. FUNCTION, cont’d
⦿ Secretion and absorption
⚫Urea and uric acid are eliminated in sweat
⚫Certain substances can be absorbed through
the skin – medications, nicotine, etc. these are
called transdermal medications
⦿ Strength and flexibility
⚫ collagen fibers in skin give it strength to
withstand trauma
⚫ flexibility fibers give it the ability to stretch and
return to normal with movement without tearing

7. Tissue vs Membranes
Tissue
— ensemble of similar
cells and their
extracellular matrix from
the same origin that
together carry out a
specific function.
Membrane
—thin sheets of tissue
or layer of cells acting as
a boundary, lining, or
partition in an organism

8. Membranes of
integumentary system
⦿ There are 4 main types of tissues
in the body, 2 of which make up skin:
⚫ Epithelial tissue
⚫ Connective tissue
⦿ Membranes surround and protect body
surfaces, including cavities that open to
the outside world (ie: nasal cavity) and
internal cavities that house organs (ie:
abdominal cavity)
Video link:
https://www.youtube.com/
watch?v=Qj2k8rYrXNM
others;
muscle tissue
nervous tissue

9. Epithelial Tissue- 3 membranes
⦿Mucous membrane
⚫ Lines body cavities that are open to the outside world,
including all hollow organs of the respiratory, digestive, urinary
and reproductive tracts
⦿Serous membrane
⚫ Line body cavities that are closed to the outside world; pleura
(encloses lungs) & peritoneum (lines abdominal cavity)
⚫ Creates thin, clear fluid called serous fluid that
lubricates between membranes to minimize friction
⦿Cutaneous membrane
⚫ A.k.a. “skin”
⚫ Basic structure of skin is keratinized cells. Keratin is the
tough protein that helps protect the skin against damage
from harmful chemicals, also found in hair and nails that
adds structural strength

10. Connective T issue - 1 membrane
⦿ Synovial membrane
⚫Line capsules surround synovial joints
(ie: knees and shoulder) and line
tendon .
⚫Serve as cushions and secrete synovial fluid
that provides cushioning and reduces
friction on moving structures

11. Epithelial tissue
⦿ Provides a lining (covering) for internal and external surfaces
of the body - lungs, digestive system, bronchioles, mouth,
nose, etc.
⦿ Epithelial tissues contain common characteristics
⚫ tightly packed cells: little extra space
⚫ free surface:
○ exposed to environment or body cavities
⚫ deep surface:
○ basement membrane to connect it to the connective tissue
⚫ lack blood supply so they receive nutrients from the surface
and absorb it through the layers
⚫ have rick supply of nerves for sensory perception
⚫ constantly reproduce by mitosis to repair daily damage

12. Epithelium is classified in 2 ways: shape and layers
SQUAMOUS - thin and flat:
found in air sacs of lungs
CUBOIDAL- cube shaped:
COLUMNAR- taller than wider
with an oval shaped nucleus
PSEUDOSTRATIFIED- various
heights. All connect to basement
membrane and may secrete
mucous.
SHAPES

13. Epithelium is classified in 2 ways: shape and layers
SIMPLE:
● 1 cell layer thick;
● all layers in contact with
basement membrane
STRATIFIED:
● 2 or more layers of cells.
● only the deepest layer of
cells have contact with the
basement membrane.
● looks like a brick wall to
provide protection
PSEUDOSTRATIFIED
● made up of pseudostratified
cells (various sizes)
LAYERS
when describing, you say simple
squamous, simple cuboidal, etc. to
identify the type and the number
of layers --- or stratified
squamous, statified columnar, etc.

14. Types of Receptors
⦿ There are several receptors found
throughout the body, these are located in
the skin
⚫Mechanoreceptors
○ Sensory cells that detect muscle contraction and
force
⚫Thermoreceptors
○ Specialized nerve cells that detect difference in
temperature; determine sensitivity of the skin
to changes – heat receptors are closer to
surface, cold receptors are deeper
⚫Chemoreceptors
○ Sensory cells that convert chemical substances
into biological signals that are transmitted to
the brain

15. Anatomy of the skin
⦿ EPIDERMIS:
⚫ Outermost layer of the skin
⚫ The skin we see
⚫ Made of five small layers(thick skin) 4 layers
everywhere else- but contains no blood
vessels or nerve cells
⚫ Most of cells within
epidermis are
keratinocytes which
produce keratin
⚫ As cells move from
granulosum to corneum, they
become more filled with

16. Epidermal layers
⚫ Layers (from outside to inside)
⦿ Stratum corneum - outermost layer, , provide
physical barrier for rest of skin layers,constantly
shed and replaced by new cells from the inner
layer – epidermis completely replaces itself
every 25-45 days
⦿ Stratum lucidum - thin layer made of flat,
transparent cells (found ONLY in soles of feet
and palms of hands)
⦿ Stratum granulosum - 2-3 layers of flat cells;
active keratinization; compact & brittle, secretes
lipids (fats) to form a lipid barrier making it
waterproof

17. ⦿ Stratum spinosum – keratinization or cells begin
here; spiny shaped cells
⚫Melanocytes are produced here and connect to
keratinocytes. They are important for
producing melanin.
⚫Also found here is Langerhans cells which
ingest foreign antigens and process them to
activate our immune system
⦿ Stratum germinativum (basale) - innermost layer;
rests on basement membrane. Keratinocytes
are created here and migrate toward the surface
(corneum) making up most of the epidermis.
Merkel cells, or touch receptors, are found here –
these cells relay information to the brain

18. Layers of
integumentary tissue
⦿ DERMIS:
⚫Considered “true skin”; thickest layer
⚫Found below epidermis
⚫Contains blood vessels, nerves, muscles,
sweat and oil glands and hair follicles
⚫Top of dermis (papillary layer) covered with
papillae – fits into the ridges of the stratum
germinativum of the epidermis
⚫The ridges form lines and make patterns that
become fingerprints and footprints

19. 2 main layers of the dermis:
1. Papillary layer:
a. top layer of the dermis
b. made of connective tissue
c. contains papillae ridges that form to the lower layer of the
epidermis and carries nutrients to the cells of the epidermis
and sensory receptors to monitor touch sensation -
creates fingerprints/toeprints
2. Reticular layer
a. dense connective tissue with elastic fibers
b. extends to the hypodermis (subcutaneous layer)

20. 2 Main types of glands within dermis
⦿ Sudoriferous glands
⚫ A.k.a. Sweat glands
⚫ Coiled tubes that extend through the dermis and
open on the surface of the skin at pores
⚫ The sweat eliminated contains water, salts and some
body wastes
⚫ 2 types of sudoriferous glands:
○ Eccrine glands – major sweat glands and cover most of the
body and open directly onto skin; highest levels in palms
and soles
⚫ Sweat is clear, acidic and about 99% water but also contains waste
products like urea, uric acid, salts and vitamin C;
○ Apocrine glands – begin to function during puberty and
are located in genital and axilla areas and secrete into
ducts through hair follicles
⚫ Secretions are milky and consist of sweat, fatty acids and proteins

22. ⦿ Sebaceous glands
⚫ A.k.a Oil glands – produce substance
called sebum
⚫ Located all over body except palms of hands
and soles of feet
⚫ Keeps skin and hair from becoming dry and
brittle
⚫ It helps prevent infections because it is an
antibacterial and antifungal secretion
⚫ When gland become plugged, the dirt and
oil accumulate and results in pimples

24. ⦿ Arrector pili muscle – small muscles attached to hair
follicles. Contraction of muscle causes hair to “stand
on end” or “goose bumps” as well as force sebum
towards surface of hair.
⦿ Arteries & Veins – transports blood flow through
system
⦿ Nerves – allows transmission of sensation to the brain
⦿ Ruffini endings – mechanoreceptor:
⚫ Responds to sustained touch and pressure to help detect ability
to grip and prevent slipping of objects
⦿ Krause end bulbs: - thermoreceptor:
⚫ Detects cold temps; found in eyes, lips, tongue,
genitals (specialized areas)
⦿ Meissner corpuscle – mechanoreceptor:
⚫ Response to texture changes and slow vibrations; most
sensitive to light touch and is concentrated in fingers and lips
⦿ Pacinian corpuscles – mechanoreceptor:
⚫ Responds to rapid changes and deep pressure
⦿ Merkel disks – mechanoreceptor:
○ Attached to cells in the stratum basale; Responds to slow changes
in position

25. 3rd layer of integumentary
tissue
⦿ Hypodermis – subcutaneous
fascia
⚫Innermost layer
⚫Made of connective tissue and
adipose (fatty) tissue
⚫Connects the skin to muscles
⚫Fat tissue: stores energy,
regulates temperature, provides
cushioning

26. Lesser known parts:
⦿ Hair – helps protect the body and covers
all body surfaces except for the palms
of the hands and the soles of the feet
⚫Alopecia – baldness, permanent hair loss
⦿ Nails – protect the fingers and toes from
injury, made of dead epidermal epithelial
cells packed closely together to form a
thick, dense surface. Will grow if nail
bed is not damaged.

27. Pigmentation
⦿ Basic skin color is inherited and determined
by the pigments in the epidermis
⦿ Melanin – blackish-brown pigment leads to
black or brown skin tint; also absorbs UV
light to tan the skin; small concentrations
form freckles
⦿ Carotine – yellow-red pigment
⦿ Albino – person with absence of color
pigments

28. Abnormal colors
⦿ Erythema – reddish color of skin caused
by burns or congestion of blood
vessels
⦿ Jaundice – yellow discoloration indicates
bile in the blood resulting from liver or
gallbladder disease
⦿ Cyanosis – bluish discoloration of the
skin caused by insufficient oxygen;
associated w/ heart, lung, and
circulatory diseases

31. Skin Injuries
⦿ Wounds produce different types of damage
to tissue parts
⚫Contusion
○ Bruising of tissue caused by blunt force –
capillaries break and leak blood under the
epidermis

32. ⦿ Incision
⚫Cutting of the skin usually by surgical
knife
⦿ Laceration
⚫A tear or cut in the skin
⦿ Puncture
⚫Hole created in the skin by a sharp,
pointed object
⦿ Abrasion
⚫Superficial scrape to the skin

33. Fungal Infections
⦿ Athlete’s foot
⦿ Ringworm
Viral Infections
⦿ Herpes varicella
⦿ Herpes zoster
⦿ Herpes simplex virus (HSV-1)
⦿ Human papilloma virus (HPV)

34. Tinea Pedis (Athlete’s foot)
⦿ Tinea is a fungal infection that occurs in
areas of the body that are moist
⦿ Symptoms include itchy skin, blisters
and cracks into open sores
⦿ Treatment is using antifungal medication
and keeping area dry and clean

35. Ringworm
⦿ Highly contagious fungal infection
⦿ Symptom Is the formation of flat or
raised circular area with a clear central
area surrounded by an itchy, scaly or
crusty outer ring
⦿ Antifungal medications are used in
treatment

36. Viral Infections
⦿ Herpes varicella
⦿ Herpes zoster
⦿ Herpes simplex virus (HSV-1)
⦿ Human Papilloma Virus (HPV)

37. Herpes varicella
⦿ A.k.a. “chickenpox”
⦿ Contagious fluid-filled blisters
⦿ Incubation period 14 days
⦿ Small fever prior to rash outbreak
⦿ Vaccine available

38. Herpes zoster
⦿ Chickenpox virus – lays
dormant but re-occurs in
adults as “shingles”
⦿ Painful, blistering rash
⦿ Headache, fever and
general achy-ness
⦿ Vaccine recommended
for >55yo.

39. Herpes simplex virus
(HSV-1)
⦿ Aka – “cold sore”
⦿ Associated with
common colds
⦿ Highly contagious and
can be transmitted to
the mouth or genital
area
⦿ 1 in 6 people have
HSV-1
⦿ Once infected, remains
dormant but can be
reactivated

40. Human papilloma virus
(HPV)
⦿ A.k.a. “warts”
⦿ Group of 150 viruses
⦿ Raised, painless growths
on skin
⦿ Can spread from one
part of body to another
⦿ Plantar warts grow
inward on soles of foot
causing sever pain

41. Bacterial Infections
⦿ Acne vulgaris
⦿ cellulitis
⦿ Impetigo

42. Acne vulgaris
⦿ Inflammation of sebaceous
glands
⦿ Cause unknown, but thought to
be related to hormone
changes
⦿ Symptoms include papules,
pustules and blackheads that
occur when follicles become
blocked
⦿ Treated w/ good skin hygiene;
antibiotic or vitamin A
ointments; avoiding makeup
and heavy creams;

43. Cellulitis
⦿ Staph infection
⦿ Inflammation and
redness of skin causing
pain
⦿ Can be life threatening if
left untreated

44. Impetigo
⦿ Highly contagious skin infection caused
by strep or staph organisms
⦿ Symptoms include erythema, oozing
vesicles, formation of yellow crusts and
lesions
⦿ Wash lesions w/ soap and water and
antibiotics

45. Inflammatory conditions
⦿ Dermatitis
⦿ Eczema
⦿ Psoriasis

46. Dermatitis
⦿ Inflammation of the skin caused
by irritants
⚫Can lead to cellulitis –
⦿ Possible allergic reactions to
detergents, soaps, cosmetics,
etc.
⦿ Symptoms include dry skin,
erythema, itching, edema,
rashes, etc.
⦿ Treated with anti-inflammatories
and antihistamines and
possible steroids

47. Eczema
⦿ Noncontagious, inflammatory
skin disorder caused by an
allergen or irritant
⦿ Symptoms include dry skin,
itching, vesicles, crusts
and scaling
⦿ Treatment involves removing
irritant and applying cortisone to
reduce inflammation

48. Psoriasis
⦿ Chronic, noncontagious,
inherited skin disease
⦿ Symptoms include thick, red
areas covered w/ white or
silver scales
⦿ No cure, treatment methods
include steroid creams, UV
light and scale removal

49. Other disorders
⦿ Decubitus ulcer
⦿ Skin cancer
⦿ Burns

50. ⚫Decubitus ulcer
○ Bed sores caused by pressure that restricts
blood flow
○ Typically occur with prolonged bed rest when
not turned often enough, usually occurs over
boney areas (hips, tailbone, elbows, etc)

51. Skin cancer
⦿ Occurs in several forms
⚫ Malignant – cancerous
⚫ Benign – non cancerous
⚫ Basal cell carcinoma, squamous cell carcinoma,
melanomas
Develops from moles, exposure to sun, prolonged
use of tanning beds, chemicals, or radiation
⦿ Treatment involves surgical removal or
radiation
⦿ Concerns (what to look for)
⚫ Asymmetry
⚫ Border irregularity
⚫ Color
⚫ diameter

52. Burns
⦿ Injuries that come from exposure to
excessive heat, chemicals, electricity, or
UV radiation
⦿ Vary in severity and can cause cell
damage or death
⦿

53. Rule of 9’s
⦿ when a large area of
skin has been
burned, practitioners
use the “rule of
nine’s” to estimate
the extent of tissue
that has been
burned