Transcript Integumentary System

October 30, 2014

Journal: What makes up the
Integumentary system?
Integumentary System
Made up of:
Skin
 Hair
 Nails
 Associated Glands

Functions:
Protection
 Keeps the body from drying out
 Stores fatty tissues to be used as an
energy source
 Produces vitamin D with the help of
sunshine
 Sensory input for your brain
 Regulates body temperature

Skin

Made up of 3
tissue layers:
–
Epidermis
– Dermis
– Subcutaneous
fascia a.k.a.
hypodermis
Epidermis
Outermost layer of skin
 Made up of 4-5 layers or stratified
squamous epithelial tissue
 Contains no blood vessels or nerve cells

Epidermis Layer Shedding


Surface cells are constantly shedding
Cells originate in the basal layer (stratum
basale) and are pushed upward towards the
surface
 As they are pushed upwards the cells die
and become filled with a protein called
keratin
 This process takes between 2 and 4 weeks
Layers of the Epidermis
Stratum corneum
Dead cells on the outermost surface of
the skin
 Often shed
 Typically flat, scaly, and keratinized
(hardened) epithelial cells
 Protect the layers underneath from
drying out

Stratum lucidum

Layer of dead, keratinized epithelial
cells only found in parts of the body
with thick skin
–

Ex: Palms and heels
Functions in protection from UV rays
Stratum granulosum

Skin layer in the middle of the
epidermis where living cells are filled
with keratin and begin to die
Stratum spinosum
Living epithelial cells that do not
receive nutrients from the dermis, but
divide at a slow rate
 Contain Langerhans cells that can
produce an immune response when
pathogens are present

Stratum basale
Living epithelial cells that receive
nutrients from the dermis and undergo
rapid mitosis to replace cells lost in the
stratum corneum
 Contains melanocytes which are
responsible for producing pigment
 Contains Merkel cells which are touch
receptors

Melanocytes
Produce melanin, the substance that is
responsible for your skin color
 Variations in skin color are due to how
much melanin is produced and how it
is distributed around your body

Skin Color
More sun = more melanin produced = tan
 Freckles occur when melanin is found
together in clumps
 Yellowish skin tone is due to carotene
 Pinkish skin tone is due to hemoglobin
 Yellow jaundice occurs when liver disease
occurs and the body can’t excrete waste

How getting a tan works
When you get a tan, what is actually happening is
that the melanocytes are producing melanin
pigment in reaction to ultraviolet light in sunlight.
The pigment has the effect of absorbing the UV
radiation in sunlight, so it protects the cells from
UV damage.
In other races, melanin production is continuous, so
the skin is always pigmented to some degree. In
these races the incidence of skin cancer is much
lower because cells are constantly protected from
UV radiation by melanin.
November 3, 2014
Objective: To describe the layers of the
skin and the accessory organs found
within them
 Journal:

–
List the layers of the epidermis from the
outside to the inside of the body.
Dermis
Layer right below the epidermis
 Thick layer of irregular connective
tissue

Two Layers within the Dermis:

Papillary Layer
–
Top layers of the dermis
– Contains thin elastic and collagen fibers
– Contains ridges that are responsible for
fingerprints

Reticular Layer
–
Below the papillary layer
– Contains tightly packed elastic and
collagen fibers
Found within the Dermis:
Blood vessels

Bring nutrients to the skin and carry
waste away from it
Collagenous and elastic fibers
Helps your skin shift when you move
your body otherwise it would tear
 Allows skin to return to its normal
shape when your body is at rest
 Stretches out over time so skin loses
it’s firmness and flexibility

Nervous tissue
Carry nerve impulses to the brain
 Connect to Merkel cells in the epidermis

Lymph Vessels

Transport fluids from the tissues to the
circulatory system
Hair follicles
Sweat Glands

Apocrine sweat glands
–
–

Located near the hair follicles, groin, and armpits
Become active around puberty and act as a
sexual attractant
Eccrine sweat glands
–
–
Located all over your skin
Regulate body temperature
** Body odor isn’t actually from sweat, but from
bacteria breaking down substances in it
Sebaceous Glands
Oil glands that keep the skin from
drying out
 Destroys pathogens on the skin as well

Subcutaneous fascia
Also known as hypodermis
 Innermost layer of skin
 Composed of fatty tissues and elastic
and fibrous connective tissue
 Connects to the muscles of your body

Lipocytes

Fat cells produce the fat needed to
protect the body and to act as
insulation for regulating temperature