Transcript File - Mr. Jaeger`s Class

Table of Contents
Chapter 17: Structure and
Movement
Section 1: The Skeletal System
Section 2: The Muscular System
Section 3: The Skin
The Skeletal System
1
Living Bones
• bones are alive
organ made of several
different tissues
• made of cells
take in nutrients and use energy
have same needs as other body
cells
The Skeletal System
1
Functions of Your Skeletal System
• skeletal system - All the bones in your
body
• framework of your body
has five major functions
1.The skeleton gives shape and support to
your body.
2.Bones protect your internal organs. For
example, ribs surround the heart and
lungs, and the skull encloses the brain.
The Skeletal System
1
Functions of Your Skeletal System
3.Major muscles are attached to bone and
help them move.
4.Blood cells are formed in the center
of many bones in soft tissue called red
marrow.
5.Major quantities of calcium and
phosphorous compounds are stored in
the skeleton for later use. Calcium and
phosphorous make bones hard.
The Skeletal System
1
Bone Structure
• have bumps, edges, round ends, rough
spots, and many pits and holes
• Muscles and ligaments attach
to some of the bumps and pits
• blood vessels and nerves
enter and leave through the holes
The Skeletal System
1
Bone Structure
• periosteum (per ee AH stee um) – covering of
a bone’s surface
.tough, tight-fitting membrane
• Small blood
vessels carry
nutrients into
the bone
The Skeletal System
1
Bone Structure
• growth and repair cells
also in the periosteum
• compact bone
and spongy
bone - under
the periosteum
The Skeletal System
1
Compact Bone
• compact bone - gives bones strength
directly under periosteum
• deposits of calcium phosphate
make bone hard
• Bone cells and blood vessels
The Skeletal System
1
Spongy Bone
• Spongy bone - toward ends of long bones
thigh and upper arm
• many small, open spaces
make bones lightweight
The Skeletal System
1
Spongy Bone
• centers of long bones
are large openings called cavities
filled with marrow
• Some is yellow
composed of fat cells
• Red marrow produces red blood cells
at a rate of 2 million to 3 million per second
The Skeletal System
1
Cartilage
• Cartilage - smooth,
slippery, thick layer
of tissue
ends of bones
• does not contain blood vessels
or minerals
The Skeletal System
1
Cartilage
• flexible and
important in joints
• acts as a shock
absorber
• makes movement easier
by reducing friction
The Skeletal System
1
Bone Formation
• Months before your
birth, your skeleton
was made of cartilage.
• Gradually the cartilage
broke down and was
replaced by bone.
The Skeletal System
1
Bone Formation
• Cartilage is replaced
slowly by bone as solid
tissue grows outward.
Over time, the bone
reshapes to include
blood vessels, nerves,
and marrow.
The Skeletal System
1
Bone Formation
• osteoblasts (AHS tee oh blasts) - Boneforming cells
deposit the minerals calcium and
phosphorous in bones
making the bone tissue hard
• At birth - more than 300 bones
• some bones grew together
now you have only 206 bones
The Skeletal System
1
Bone Formation
• Osteoblasts build up bone.
• Osteoclast - breaks down bone tissue
in other areas of bone
• release calcium and phosphorous
into the bloodstream
• maintains calcium and phosphorous
in your blood
The Skeletal System
1
Joints
• Joint - Anyplace where two or more bones
come together
• bones kept far enough apart
by thin layer of cartilage
• Ligament - tough band of tissue
holds bones in place
• Muscles move bones by moving joints
The Skeletal System
1
Immovable Joints
• immovable joint - little or no movement
• skull and pelvis
The Skeletal System
1
Movable Joints
• pivot joint - one bone
rotates
in a ring of another bone
that does not move
• Example - Turning
your head
The Skeletal System
1
Movable Joints
• ball-and-socket joint bone with a rounded end
fits into cuplike cavity
on another bone
• wider range of motion
than pivot joint
• legs and arms can swing
in almost any direction
The Skeletal System
1
Movable Joints
• hinge joint - back-and-forth
movement
like hinges on a door
Elbows, knees, and fingers
• smaller range of motion
not dislocated as easily
The Skeletal System
1
Movable Joints
• gliding joint - one
part of a bone
slides over another
bone
The Skeletal System
1
Movable Joints
• back-and-forth
motion
• found in your wrists,
ankles, and between
vertebrae
• used the most in
your body
The Skeletal System
1
Moving Smoothly
• Without the protection of the cartilage at the
end of your bones, they also would wear
away at the joints.
• Cartilage helps make joint movement easier.
It reduces friction and allows bones to slide
more easily over each other.
The Skeletal System
1
Common Joint Problems
• Arthritis - symptoms: pain, stiffness, and
swelling of joints
• About one out of every seven people in U. S.
• Osteoarthritis - cartilage breaks down
because of years of use.
• Rheumatoid arthritis - ongoing condition body’s immune system tries to destroy its
own tissues
Section Check
1
Question 1
Which is NOT a function of your skeletal
system?
A. gives shape and support to body
B. protects internal organs
C. produces blood cells
D. produces calcium and phosphorous
Section Check
1
Answer
The answer is D. Calcium and phosphorous are
stored in bones but they are not produced in
bones
Section Check
1
Question 2
What type of joint is shown in this diagram?
A. ball-and-socket
B. gliding
C. hinge
D. immovable
Section Check
1
Answer
The answer is C. A hinge joint has back and
forth movement like the hinges on a door.
Elbows, knees, and fingers have hinge joints.
Section Check
1
Question 3
Which is a place where two or more bones
come together?
A. cartilage
B. ligament
C. muscle
D. joint
Section Check
1
Answer
The answer is D. Cartilage keeps the bones in
joints far enough apart that they don’t rub
together.
The Muscular System
2
Movement of the Human Body
• muscle - organ that can relax,
contract, and provide force to
move body parts
• Muscles help make all of your
daily movements possible.
The Muscular System
2
Movement of the Human Body
• energy is used
work is done
• Some muscles are always
moving
The Muscular System
2
Muscle Control
• voluntary muscles - Muscles you are able to
control
• hand, arm, and leg muscles
• You can choose to move them or not
move them.
The Muscular System
2
Muscle Control
• Involuntary muscles - muscles you can’t
control consciously
• go on working all day long,
all your life
• Blood gets pumped through blood vessels,
and food is moved through your digestive
system
The Muscular System
2
Your Body’s Simple Machines—
Levers
• muscles, bones, and joints working together like a lever
• bones are rods,
joints are fulcrums,
muscles provide the force
• Levers are classified into three types—
first-class, second-class, and third-class,
all are found in human body
The Muscular System
2
Classification of Muscle Tissue
• skeletal muscles - muscles that move bones
The Muscular System
2
Classification of Muscle Tissue
• Tendons - thick bands of tissue
attaches muscle to bones
The Muscular System
2
Classification of Muscle Tissue
• striated (STRI ay tud) - appear striped
skeletal muscle cells
• Skeletal muscles are voluntary muscles
• contract quickly and tire more easily
than involuntary muscles
The Muscular System
2
Classification of Muscle Tissue
• Cardiac muscle - only in heart
• is striated
• contracts about 70
times per minute
every day of your life
The Muscular System
2
Classification of Muscle Tissue
• Smooth muscles - found in intestines,
bladder, blood vessels, and other internal
organs
• nonstriated, involuntary
muscles
slowly contract and relax
• one or more layers
The Muscular System
2
Working Muscles
• pairs of skeletal muscles work together
• When one
muscle of a
pair contracts,
the other
muscle relaxes,
or returns to its
original length.
Click image to view movie.
The Muscular System
2
Working Muscles
• always pull - never push
• When the muscles on the back of your upper
leg contract, they shorten and pull your lower
leg back and up.
• When you straighten
your leg, the back
muscles lengthen and
relax, and the muscles
on the front of your
upper leg contract.
The Muscular System
2
Changes in Muscles
• muscles can become larger or smaller
depending on whether or not they are used
• Some change in size because of increase in
number of muscle cells
• most change is because individual muscle
cells become larger
The Muscular System
2
Changes in Muscles
• only nonactive pastimes = muscles become
soft and flabby
will lack strength
• Muscles that aren’t exercised
become smaller in size
The Muscular System
2
How Muscles Move
• muscles need energy
to contract and relax
• blood carries energyrich molecules
to your muscle cells where it is released
• As muscle contracts, energy changes to
mechanical energy (movement)
and thermal energy (heat)
The Muscular System
2
How Muscles Move
• When supply of energy is used up,
muscle becomes tired
and needs rest
• During resting, blood supplies more energy
to your muscle cells
• heat produced by contractions
helps keep body temperature constant
Section Check
2
Question 1
The skeletal and muscular system working
together can be described as a _______.
A. lever
B. inclined plane
C. screw
D. wheel and axle
Section Check
2
Answer
The correct answer is A. In your body, bones
are rods, joints are fulcrums, and contraction
and relaxation of muscles provide the force to
move body parts.
Section Check
2
Question 2
What type of muscle makes up this organ?
A. cardiac
B. skeletal
C. smooth
D. rough
Section Check
2
Answer
The answer is A. Cardiac muscle is found only
in the heart.
Section Check
2
Question 3
Describe how muscles increase in size.
Answer
Muscles that are given regular exercise respond
quickly to stimuli. Some change in muscle size
is due to an increase in the number of muscle
cells. However, most increase in size is
because individual muscle cells become larger.
The Skin
3
Your Largest Organ
• skin - largest organ of the body
• largest sense organ
• Much of the information you receive about
your environment comes through your skin
The Skin
3
Your Largest Organ
The Skin
3
Melanin
• Melanin (MEL uh nun) - pigment that
protects skin
and gives it color
• different amounts
of melanin results
in differences in
skin color
The Skin
3
Melanin
• ultraviolet rays - increases melanin production
and skin becomes darker
• Lighter skin tones
have less protection
from the Sun
• burns more easily
and may be more
susceptible to skin
cancer
The Skin
3
Skin Functions
• most important function is protection
• protective covering over the body that
prevents physical and chemical injury
• Some bacteria and other disease-causing
organisms cannot pass through the skin as
long as it is unbroken.
The Skin
3
Skin Functions
• Glands in skin secrete fluids
that can damage or destroy some bacteria
• slows down water loss from body tissues
• Specialized nerve cells in skin detect and
relay information to the brain,
making it a sensory organ
The Skin
3
Vitamin D Formation
• vitamin D formation - produced in ultraviolet
light
from a fatlike molecule in your epidermis
• is essential for good health
helps body absorb calcium into blood
from food in digestive tract
The Skin
3
Heat and Waste Exchange
• Humans can withstand a limited range of
body temperatures.
The Skin
3
Heat and Waste Exchange
• plays an important role
in regulating body temperature
• Blood vessels in skin can help release or
hold heat.
If blood vessels expand (dilate), blood flow
increases and heat is released
• less heat is released when blood vessels
constrict
The Skin
3
Heat and Waste Exchange
• Sweat glands help regulate body temp
and excrete wastes
• When blood vessels dilate, pores open that
lead to sweat glands
• Perspiration (sweat), moves out onto skin
• Heat transfers from body to sweat on skin
• sweat evaporates - removing heat
and cooling skin
The Skin
3
Heat and Waste Exchange
• Wastes produced in cells can act as poisons
• sweat glands release water, salt, and other
waste products
The Skin
3
Skin Injuries and Repair
• skin often is bruised, scratched, burned,
ripped, and exposed to harsh conditions like
cold and dry air
• produces new
cells in its
epidermis and
repairs tears in
the dermis.
The Skin
3
Bruises
• Bruise - skin is not broken
but tiny blood vessels underneath skin have
burst
• Red blood cells leak into tissue and break
down,
releasing a chemical called hemoglobin
• hemoglobin gradually breaks down into its
pigment,
causes bruised area to turn shades of blue,
red, and purple.
The Skin
3
Bruises
• Swelling also may
occur.
• eventually turns
yellow as the
pigment is broken
down
The Skin
3
Bruises
• After all pigment is
absorbed into
bloodstream, bruise
disappears and skin
looks natural again
The Skin
3
Cuts
• Blood flows out of a cut until a clot forms
• scab forms to prevent bacteria from entering
• Cells in surrounding blood vessels fight
infection while skin cells beneath scab grow
to fill gap in skin
• scab falls off, leaving new skin behind
• scar may develop if cut is large enough
The Skin
3
Cuts
• When severe burns, some diseases, and
surgeries result in injury to large areas of skin,
not enough skin cells are left to divide and
replace lost layer
• If not treated, can lead to
rapid water loss from
skin and muscle tissues,
leading to infection and
possible death
The Skin
3
Skin Grafts
• skin grafts - pieces of skin cut from one part
of a person’s body
and moved to an injured or burned area
• kept alive by nearby blood vessels
soon becomes part of surrounding skin.
• Successful grafts must be taken from
victim’s own body
or possibly an identical twin
The Skin
3
Skin Grafts
• Since 1880s, doctors have used skin of dead
humans (cadavers) to treat temporarily severe
burn victims who have little healthy skin left.
• body usually rejects grafted skin, so it must
be replaced continually until burn heals
The Skin
3
Skin Grafts
• A recent advancement in skin repair uses
temporary grafts from cadavers to prevent
immediate infections,
• while scientists grow large sheets of
epidermis from small pieces of burn victim’s
healthy skin
• After 19 to 21 days, cadaver skin patch is
removed and new epidermis is applied
Section Check
3
Question 1
Which lies directly below the epidermis?
A. dermis
B. fatty layer
C. hairs
D. melanin
Section Check
3
Answer
The answer is A. This layer is thicker than the
epidermis and contains many blood vessels,
nerves, muscles, oil and sweat glands, and
other structures.
Section Check
3
Question 2
Which is NOT a function of skin?
A. digestion of nutrients
B. formation of vitamin D
C. protection
D. regulation of body temperature
Section Check
3
Answer
The answer is A. The digestive system is
responsible for processing nutrients.
Section Check
3
Question 3
Explain how a bruise forms.
Answer
A bruise forms when capillaries and other tiny
blood vessels beneath the skin burst. Red blood
cells from these broken blood vessels leak into
the surrounding tissue and the hemoglobin that
is released eventually breaks down into its
pigments which give a bruise its color.
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