The Integumentary System:
The Skin
The Integumentary System
Integument is skin
 Skin and its appendages make up the
integumentary system
 A fatty layer (hypodermis) lies deep to it
 Two distinct regions

 Epidermis
 Dermis
Skin
Your skin is your largest organ
 It is your first line of defense against
disease and damage
 It is made of several layers

Functions of skin

Protection
 Cushions
and insulates and is waterproof
 Protects from chemicals, heat, cold, bacteria
 Screens UV
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Synthesizes vitamin D with UV
Regulates body heat
Prevents unnecessary water loss
Sensory reception (nerve endings)
Layers of Skin

Epidermis
 Uppermost
layer of skin
Contains dead and living cells
 New cells are replaced daily old ones slough off
(they shed)

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Dermis Inner
thicker layer of skin
 Contains:
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Blood vessels
Nerve receptors
Hair follicles
Sebaceous glands
Sweat glands
 Oil glands
 Wax glands

Remember…
 Four
basic types of tissue
– epidermis just discussed
Connective tissue - dermis
Muscle tissue
Nervous tissue
Epithelium
Dermis
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Strong, flexible connective tissue: your “hide”
Rich supply of nerves and vessels
Critical role in temperature regulation (the
vessels)
Two layers (see next slides)
– includes dermal papillae- makes
fingerprints
 Reticular – “reticulum” (network) of collagen and
reticular fibers
 Papillary
Skin Layers

Subcutaneous Layer- lies below the
dermis layer, not really a skin layer

Contains
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Fat cells
Fibers used to attach skin to muscle
*Dermis layers
*Dermal papillae
*
*
Skin Color

Skin pigments
 Melanin-
dark skin pigment (causes human
skin colors)
 Where there are darker colors on the skin
there is a higher concentration of melanin in
that area
Freckles
 Moles
 birthmarks

Skin color

Three skin pigments
 Melanin:
the most important
 Carotene: from carrots and yellow vegies
 Hemoglobin: the pink of light skin

Melanin
 Variations
in color
 Protection from UV light by producing vitamin
D
How does our skin protect us?

Forming
 callus-
a thickened area of epidermis caused
by rubbing or pressure
 Blisters- area of skin when the layers of skin
separate due to excessive friction or intense
heat
 Melanin produces vitamin D- “natural
sunblock”
Sweat glands

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Prevent overheating
500 cc to 12
Liters/day! (is
mostly water)
Humans most
efficient (only
mammals have)
Produced in
response to stress
as well as heat
Fingerprints, palmprints, footprints
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Dermal papillae lie atop dermal ridges
Elevate the overlying epidermis into epidermal ridges
Are “sweat films” because of sweat pores
Genetically determined
Flexion creases

Deep dermis, from continual folding
Fibers

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Collagen: strength and resilience
Elastic fibers: stretch-recoil

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Striae: stretch marks
Tension lines (or lines of cleavage)

The direction the bundles
of fibers are directed
The dermis is the receptive
site for the pigment of tattoos
Disorders of the integumentary system

Burns
 Threat
to life
Catastrophic loss of body fluids
 Dehydration and fatal circulatory shock
 Infection

 Types
First degree – epidermis: redness (e.g. sunburn)
 Second degree – epidermis and upper dermis: blister
 Third degree - full thickness

Infections
 Skin cancer

Burns
First-degree
(epidermis only; redness)
Second-degree
(epidermis and dermis,
with blistering)
Third-degree
(full thickness, destroying
epidermis, dermis, often part
of hypodermis)
SKELETAL SYSTEM
BONES & JOINTS
Functions of the Bones
1. Support
2. Protection
3. Movement
4. Storage (minerals like calcium and phosphorous)
5. Hematopoiesis (makes new blood cells in the bone
marrow)
Fig. 6.21
Bones
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The adult human skeleton has 206 bones
Bones store minerals (calcium) and make blood
cells (in the center of the bone, bone marrow)
Are made of mineral deposits of calcium and
phosphorous
There small spaces that contain blood vessels
(veins, arteries, and capillaries)
The blood vessels and surrounding bone
materials makes up an osteon (bone cell)
Broken Bones
•
A broken bone is a fractured bone:
•
Bones can break in many ways:
•
•
•
Incomplete fracture- when there is only a crack, but
not a break
Complete fracture- when the bone breaks completely
in two
Comminuted fracture- fractures that splinter the
bone
JOINTS
JOINTS
= a site where 2 or more bones
come together with or without
movement
JOINTS
1.
2.
3.
Hinge joints
= bend in only one direction, like a door hinge
flexion & extension movements possible
e.g.: elbow, knee
Gliding Joints= allows bones to slide across one another, and allows some
twisting movement
Like the bones between the vertebrae
Ball & socket joints
= ball – shaped head of one bone fits into a
socket – like concavity of another
= free movements possible:
e.g. shoulder and hip
Joints
4.
Pivot Joint=allows for some circular movement
e.g. The two bones of the forearm near the elbow
5.
Fused Joints= do not allow any movement
They become permanently fused together
e.g. Bones of the skull
Muscles
My muscles are important because
they…
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Hold my organs in place
Hold my bones together
so that I can move
Help me chew my food
Open and close my
eyelids
Pump my blood
Allow me to run and
play
Help me to smile!
Muscles & the Skeleton
Skeletal muscles cause the skeleton to
move at joints
 They are attached to skeleton by
tendons.
 Tendons transmit muscle force to the
bone.
 Tendons are made of collagen fibres &
are very strong & stiff

Functions of the Muscular System

The characteristics of muscle tissue enable it
to perform some important functions, including:

Movement – both voluntary & involuntary

Maintaining posture

Supporting soft tissues within body cavities

Guarding entrances & exits of the body

Maintaining body temperature
Muscular System

This system is responsible for movement
of the body:
 But
it cannot do this alone. Help is required
from the nerves, joints, and bones.


–They work together as an orchestra, each
playing their part in perfect harmony
Muscles work by pulling never pushing
Muscular System
Muscles are responsible for all types of
body movement
 3 basic muscle types are found in the body

 Skeletal
muscle
 Cardiac muscle
 Smooth muscle
Types of Muscles

Voluntary: muscles you can control, they
are subject to one’s will
 Skeletal
muscles- move your skeleton/bones
 Have striations- they have a banded pattern,
appears layered
Characteristics of the Skeletal Muscles

Most are attached by tendons to bones

Striated – have visible banding

Voluntary – subject to conscious control
Anatomy of skeletal muscles
epimysium
tendon
perimysium
Muscle
Fascicle
Surrounded by
perimysium
Skeletal
muscle
Surrounded by
epimysium
endomysium
Skeletal
muscle
fiber (cell)
Surrounded by
endomysium
Play IP Anatomy of Skeletal muscles (IP p. 4-6)
Characteristics of Cardiac Muscle
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Similar to skeletal
muscle cardiac muscle
has striations
These striations are not
as pronounced in
cardiac muscles as in
skeletal muscle
It is the only involuntary
muscle that is striated
Found only in the heart
Smooth Muscle Characteristics
• Has no striations
• Involuntary – no conscious control
• Found mainly in the walls of hollow organs
• Stomach, intestines, blood vessels, and
other internal organs
• The heart is involuntary, but not smooth
muscle
• Slow, sustained and tireless
• They are constantly in motion and do not
tire as do skeletal muscles
Smooth Muscle
Comparison of Muscle Tissue
How Muscles Work

Skeletal muscles work in pairs
 When
your bicep contracts your triceps relax
 When the triceps contract your bicep relaxes

Many skeletal muscles extend across at
least one joint to 2 different bones
 The
Sartorius (longest muscle in body)
attaches to the top of the hip bone and
extends across the hip and knee connecting
to the tibia
How Muscles Work

Some muscles do not extend across joints
but rather movement in skin or other
muscles
 Tongue
and throat muscles do not extend
over joints but they move to allow swallowing
Temporalis
Frontal
Obicularis oculi
Obicularis oris
Masseter
Sternoclediomastoid
Functions of Muscles

Muscles keep you warm by contracting
 When
you are cold your body shivers in an
attempt to warm you up by increasing muscle
contractions and thereby producing heat

They keep your body erect (standing up)
 Even
when you are still, standing or sitting,
your muscles are working and thereby can
keep your body warm
 This is why yoga is so effective in working
muscles, prolonged muscle contractions
More Muscle Functions

When muscles in your skin contract
making the hair follicles stand upright your
skin around the hair follicle also stands up
and causes…
 Goose
bumps
Goose Bumps
How Muscles Work

Muscles need energy to function, so
where does that energy come from
 Energy
is stored in the body as glucose
(sugar)
 It is carried by the blood to the muscles where
the muscles break down the glucose into
usable energy

In order to break down glucose the body needs
oxygen
How Muscles Work

When the muscles break down sugar, with
the use of oxygen, it is aerobic
respiration
 The
oxygen comes to the muscles from the
lungs via arteries so that they muscles can
break the sugar down into usable energy for
the body
How Muscles Work
When you work or play hard, like when
running, you begin to breathe faster in
attempts to bring more oxygen into your
blood so that your muscles can continue to
work (break down sugar)
 When you do not have sufficient oxygen
your muscles undergo lactic acid
fermentation producing lactic acid in the
muscles

How Muscles Work

A build up of lactic acid in your muscles
causes them to become sore or cramp up
 …have
you gotten tired or sore muscles the
day following a hard workout or a day of hard
play?
 This is also how you get a Charlie horse