Transcript Integumentary System and Crayfish Powerpoint

Major roles of the
Integumentary System
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protection
maintenance of normal
body temperature
storage (of fat)
synthesis (of vitamin D)
excretion (of salts, water
and wastes in sweat)
sensory perception
The Skin: 3 Major layers
Did You
Know?...
 At 8-10
pounds, the
skin is bodies
largest organ!
The Epidermis
 The epidermis is the outer
layer of skin. The
thickness of the epidermis
varies in different types of
skin. It is the thinnest on
the ______ at .05 mm and
the thickest on ______ at
1.5 mm.
 Cells of the epidermis are
constantly sloughing off
and replacing
themselves…
The Epidermis cont…
5 layers
 Cells are shaped like
columns at the base and
migrate upward, as dead
cells are continuously
sloughed off at the surface
•stratum corneum
•stratum licidum
•stratum granulosum
•stratum spinosum
•stratum basale
Which layer of the epidermis is this?
Specialized Epidermal Cells
 The melanocyte- produces pigment
(melanin)
 The Langerhans' cell- frontline defense of
the immune system in the skin
They aid in grasping objects, scratching, and protecting fingers and toes.
The Dermis
 This layer varies in
thickness as well,
depending on the area
of the body. It is a mere
0.3 mm on the eyelid
and 3.0 mm on your
back.
 The dermis is
composed of 3 types of
tissue….
The Dermis cont…
 2 types of tissue that are present
throughout (not in layers).
 collagen
 elastic tissue
Dermis Tissue: Collagen
 Collagen is the most abundant and
important structural protein in your
body. It strengthens and supports
many body tissues from the outside
creating an “extracellular matrix.”
Dermis: Elastic tissue
 Elastic protein fibers made by cells called
fibroblasts provide protection for tissues
underneath the dermis as well as the
pliability we associate with the skin.
Specialized Dermal Cells
 erector pili muscle cells support hair follicles.
 oil (sebaceous) glands, scent glands, and
sweat glands are associated with the follicle.
 Blood vessels and nerves course through this
layer. The nerves transmit sensations of pain,
pressure itch, and temperature, and blood
vessels facilitate gas exchange.
The Importance of Glands
 Sweat glands play
an important role in
keeping the body cool
 sebaceous glands
secrete sebum which
has waterproof and
antimicrobial
properties
What makes these hairs stand on end? Why?
Can you name
structures 1-4?
Layer 3: The Subcutaneous
 Also referred to as the “hypodermis,”
this layer of the skin is composed
primarily of adipose tissue (fat). This
layer plays a key role in insulating the
body and regulating the temperature of
the skin.
 The hypodermis can vary significantly in
thickness and incorporates larger blood
vessels and nerves.
Nails
 Your nails extend from the
epidermis and contain a
tough protein called
keratin. They play an
important role in grasping
objects, scratching, and
protecting fingers and
toes.
Did you Know?
 Your fingernails grow about 5 times faster
than your toenails!
Hair
 Also composed of the
protein keratin hair
acts as an effective
insulator between you
and the environment.
 hair follicles originate
in the dermis.
Did You Know?
 Hair can grow as
little as 0.1 inches
per month or as fast
as 0.5 inches per
month depending
on genetics and
your diet.
Aging and the
integumentary system
Marked declines in:
 Cell division in stratum basale
 Melanocyte production
 Glandular activity
 Hair follicle function
 Elastic fiber function in dermis
 Blood supply to skin
 Rate of repair
Disorders of the skin
•Lesions and tumors
•infections (bacterial, viral, fungal, parasitic)
•inflammatory reactions and allergies
•Genetic diseases
•acne
Anatomy of a Pimple