Chapter Introduction
Lesson 1
The Skeletal
System
Lesson 2
The Muscular
System
Lesson 3
The Skin
Chapter Wrap-Up
How do bones,
muscles, and skin
help maintain the
body’s homeostasis?
What do you think?
Before you begin, decide if you agree or
disagree with each of these statements.
As you view this presentation, see if you
change your mind about any of the
statements.
Do you agree or disagree?
1. Bones protect internal organs.
2. Bones do not change during a person’s
lifetime.
3. The same type of muscle that moves
bones also pumps blood through the
heart.
Do you agree or disagree?
4. Muscles cannot push bones.
5. Skin helps regulate body temperature.
6. Skin is made of two layers of tissue.
The Skeletal System
• What does the skeletal system do?
• How do the parts of the skeletal
system work together?
• How does the skeletal system interact
with other body systems?
The Skeletal System
• skeletal system
• ligament
• cartilage
• arthritis
• periosteum
• osteoporosis
• joint
Functions of the Skeletal System
• The skeletal system contains bones
as well as other structures that connect
and protect the bones and support
other functions in the body.
• Your skeleton is part of your skeletal
system and contains more than 200
bones.
17.2
The skeletal system provides support and
protection.
Bones are living tissue. The skeleton
is the body's framework and has two
main divisions, the axial skeleton
and the appendicular skeleton.
Bones come together at joints.
skeletal system
compact bone
spongy bone
axial skeleton
Angular Movement (elbow)
appendicular
skeleton
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OUTLINE
• Bones provide
support that helps
you sit up, stand, and
move your body.
Functions of the Skeletal System (cont.)
• The skeletal system and the muscular
system work together and move your
body.
• Bones in your skeleton protect soft
fragile tissue and internal organs like
the spinal cord, heart, and lungs.
Functions of the Skeletal System (cont.)
tissue
Science Use a group of the same
type of cells that perform a
specific function within an
organism
Common Use a soft, thin paper
Functions of the Skeletal System (cont.)
• Bones produce and store materials
needed by your body.
• Red blood cells are produced inside
your bones.
• Bones store fat and calcium.
• When your body needs calcium, it is
released from bones into the blood.
Functions of the Skeletal System (cont.)
What are the major functions
of the skeletal system?
A bone is an organ composed of two types of
living tissue: compact and spongy.
Structure of Bones
• The hard, outer portions of bones are
made of a dense web of fibers called
compact bone tissue.
• The small holes in spongy bone tissue
make it less dense than a compact
bone.
Structure of Bones (cont.)
• The insides of most bones contain
bone marrow.
• Red bone marrow, found in the spongy
ends of long bones and in some flat
bones, is the tissue where red blood
cells are made.
• Yellow bone marrow stores fat and is
found inside the longest part of long
bones.
Structure of Bones (cont.)
• Cartilage is a strong,
flexible tissue that
covers the ends of
bones.
• Cartilage prevents the
surfaces of bones from
rubbing against each
other and reduces
friction.
Structure of Bones (cont.)
• The periosteum is a membrane that
surrounds bone.
• This thin tissue contains blood vessels
and nerves as well as cells that
produce new bone tissue.
• The periosteum nourishes bones and
helps them function and grow properly,
as well as heal after injury.
Structure of Bones (cont.)
The long bones in children and young
teens have regions of bone growth,
called growth plates, that produce new
bone cells.
Growth continues until adulthood, when
most of the cartilage has turned to bone.
Joints
• A joint is where two or more bones
meet.
• Joints provide flexibility and enable the
skeleton to move.
• Bones are connected to other bones by
tissues called ligaments.
• When the bones in joints move,
ligaments stretch and keep the bones
from shifting away from each other.
Joints (cont.)
ligament
from Latin ligare, means “to bind,
tie”
•
The skull and crossbones flying from a pirate ship have long been a
symbol of death. Therefore, you might think that bones are dead
structures made of rocklike material. This isn't true. The bones in your
body are very much alive!
•
Bones are living structures with 5 functions:
•
protect internal organs
•
support the body
•
make blood cells
•
store minerals
•
provide for muscle attachment
•
A point where two or more bones connect is called a joint. There are
two different types of joints in the body:
•
Movable joints (like ball-and-socket, hinge, gliding and pivot joints)
•
Immovable joints (like the bones of the skull and pelvis) which allow
little or no movement
Joints (cont.)
• Immovable joints are parts of your
skeleton made of bones that connect
but do not move.
• Your skull contains several immovable
joints.
• The body’s moveable joints allow for a
wide range of motion.
• The three types of movable joints are:
ball and socket, hinge, and pivot.
Joints (cont.)
How do ligaments and
cartilage help the skeletal
system function?
Bone Injuries and Diseases
• A broken bone is called a fracture.
• Broken bones are able to repair
themselves, but it is a slow process
because a broken bone must be held
together while it heals.
• Arthritis is a disease in which joints
become irritated or inflamed, such as
when cartilage in joints is damaged or
wears away.
Osteoporosis is a common bone disease
which causes bones to weaken and become
brittle.
Healthy Bones
• One of the best ways to keep bones
healthy is to exercise.
• Without exercise, bones weaken and
lose mass.
• Bones need a balanced diet that
includes calcium and Vitamin D.
The Skeletal System and Homeostasis
• Because bones supply calcium to your
nerves, muscles, and heart, a healthy
skeletal system is important in
maintaining your body’s homeostasis.
• Working together with muscles, bones
enable you to move away from
unpleasant stimuli or danger.
• Skeletal system game
• The virtual body
• Body works games
• Locate the bones
• Whack a bone
• Virtual knee surgery
• Another bone game
How does the skeletal system
help the body maintain
homeostasis?
• The skeletal system contains all of
the bones, ligaments, and cartilage
in the body.
• Bones connect to each other at
joints.
• Osteoporosis is a disease that
causes bones to weaken and
become brittle.
How many bones does the human
body have?
A. about 500
B. more than 200
C. 2,000
D. about 150
What are bones attached to that
enable them to move?
A. organs
B. cartilage
C. marrow
D. muscles
Where are red blood cells are
made?
A. spongy bone tissue
B. yellow bone marrow
C. compact bone tissue
D. red bone marrow
Do you agree or disagree?
1. Bones protect internal organs.
2. Bones do not change during a person’s
lifetime.
The Muscular System
• What does the muscular system do?
• How do types of muscle differ?
• How does the muscular system
interact with other body systems?
The Muscular System
• muscle
• involuntary muscle
• skeletal muscle
• smooth muscle
• voluntary muscle
• cardiac muscle
Functions of the Muscular System
• A muscle is made of strong tissue that
can contract in an orderly way.
• When a muscle contracts, the cells of
the muscle become shorter.
• When a muscle relaxes, the cells
return to their original length.
Functions of the Muscular System (cont.)
• Bones move when muscles contract.
• There are many muscles in your body
that are not attached to bones.
• The contraction of these muscles
cause blood and food to move
throughout your body.
Functions of the Muscular System (cont.)
What is one major function of
the muscular system?
Functions of the Muscular System (cont.)
• Muscles that are attached to
bones support your body and
help you balance.
• Muscles protect your body by
covering most of your
skeleton and most of the
organs inside your body
like a layer of padding.
Tendons attach muscles to bones and help
keep joints in place when your body moves.
Functions of the Muscular System (cont.)
• Shivering occurs when muscles
contract rapidly and change chemical
energy to thermal energy, thereby
raising your body’s temperature.
• Muscles also change chemical energy
to thermal energy during exercise.
Types of Muscles
• Skeletal muscle is the type of muscle
that attaches to bones.
• Skeletal muscles are also called
voluntary muscles, which are
muscles you can consciously control.
Skeletal muscles move bones by pulling
them and working in pairs.
Types of Muscles (cont.)
• Your skeletal muscles can change
throughout your lifetime.
• Exercise allows muscle cells to
increase in size, making the entire
muscle larger and stronger.
Muscular System
Major Muscles
Because there are so many skeletal muscles in
your body, we can't list them all here. But here
are a few of the major ones:
•
In each of your shoulders is a deltoid (say: del-toyd) muscle.
Your deltoid muscles help you move your shoulders every
which way — from swinging a softball bat to shrugging your
shoulders when you're not sure of an answer.
•
The pectoralis (say: pek-tuh-rah-lus) muscles are found on
each side of your upper chest. These are usually called
pectorals (say: pek-tuh-rulz), or pecs, for short. When many
boys hit puberty, their pectoral muscles become larger. Many
athletes and bodybuilders have large pecs, too.
Below these pectorals, down under your rib cage, are your rectus abdominus
(say: rek-tus ab-dahm-uh-nus) muscles, or abdominals (say: ab-dahm-uhnulz). They are also sometimes called abs for short.
When you make a muscle in your arm, you tense your biceps (say: bye-seps)
muscle. When you contract your biceps muscle, you can actually see it push up
under your skin.
Your quadriceps (say: kwad-ruh-seps), or quads, are the muscles on the front
of your thighs. Many people who run, bike, or play sports develop large, strong
quads.
And when it's time for you to take a seat? You'll be sitting on your gluteus
maximus (say: gloot-ee-us mak-suh-mus), the muscle that's under the skin
and fat in your behind!
17.3
The muscular system makes movement possible.
Types of muscle
skeletal
muscle,
voluntary
smooth
muscle,
involuntary
cardiac
muscle,
involuntary
Function
moves bones,
maintains posture,
maintains body
temperature
moves internal
organs, such as
the intestines
pumps blood
throughout
the body
CHAPTER
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Types of Muscles (cont.)
• Your heart is made of
cardiac muscles, which
are found only in the heart.
• A cardiac muscle is a type of
involuntary muscle, which
is muscle you cannot
consciously control.
Types of Muscles (cont.)
cardiac
from Greek kardia, means “heart”
Types of Muscles (cont.)
• When cardiac muscles contract and
relax, they pump blood through your
heart and through vessels throughout
your body.
• Cardiac cells send signals to other
cardiac cells so that they all contract at
the same time.
Types of Muscles (cont.)
• Smooth muscles are involuntary
muscles, named for their smooth
appearance, that line blood vessels
and many organs.
• Contraction of smooth
muscles helps move
material through the
body, such as food in the
stomach and blood through
the vessels.
Types of Muscles (cont.)
What are the three types of
muscles?
Exercise helps keep muscles healthy.
Muscle cells decrease in size and
strength without exercise.
The Muscular System and Homeostasis
• Muscle contractions convert chemical
energy to thermal energy and keep
your body warm.
• When you exercise, the cardiac
muscles of your heart help maintain
homeostasis by contracting more often.
• When it contracts faster, the heart
pumps more blood and more oxygen is
carried to the cells.
The Muscular System and Homeostasis
(cont.)
How do muscles help
maintain homeostasis in the
body?
• Your muscular system is made of
different types of muscles. Skeletal
muscles attach to bone and are
muscles you can control.
• Smooth muscles line
blood vessels and
many internal organs.
• The heart is made of cardiac muscle.
What happens to a muscle when
it contracts?
A. it becomes stronger
B. it becomes shorter
C. it becomes longer
D. it bends
What kind of muscles line blood
vessels and many organs?
A. smooth muscles
B. voluntary muscles
C. cardiac muscles
D. skeletal muscles
What is the term used to describe
muscles that you can consciously
control?
A. skeletal
B. involuntary
C. cardiac
D. voluntary
Do you agree or disagree?
3. The same type of muscle that moves
bones also pumps blood through the
heart.
4. Muscles cannot push bones.
The Skin
• What does the skin do?
• How do the three layers of skin differ?
• How does the skin interact with other
body systems?
The Skin
• integumentary system
• epidermis
• melanin
• dermis
• bruise
Functions of the Skin
• Skin is the largest organ in your body.
• Skin is part of the integumentary
system, which includes all the external
coverings of the body including nails
and hair.
Functions of the Skin (cont.)
integumentary
from Latin integere, means “to
cover”
Functions of the Skin (cont.)
• Skin covers your bones and muscles
and protects them from the external
environment.
• It protects the cells and tissues under
the skin from damage.
• Skin is the first line of defense against
dirt, bacteria, viruses, and other
substances that might enter the body.
Functions of the Skin (cont.)
• Sensory receptors are special cells in
your skin that detect texture and
temperature and sense pain.
• The more sensory receptors there are in
an area of skin, the more sensitive it is.
Functions of the Skin (cont.)
• Skin helps control body temperature.
• Skin lowers your body temperature by
producing sweat, which evaporates
and allows excess thermal energy to
leave the body.
Functions of the Skin (cont.)
• Skin also lowers body temperature by
releasing thermal energy from blood
vessels.
• If your skin is exposed to sunlight, it
can make vitamin D which helps it
absorb calcium and phosphorous to
promote bone growth.
Functions of the Skin (cont.)
How does skin regulate body
temperature?
Functions of the Skin (cont.)
• The skin helps to eliminate waste
products produced by normal cellular
processes.
• Water, salts, and other waste products
are removed through the pores.
Structures of the Skin
• The epidermis is the outermost layer of
skin and the only layer in direct contact
with the outside environment.
• Cells of the epidermis are constantly
shed and replaced by new cells.
• The epidermis produces melanin, which
is a pigment that protects the body by
absorbing some of the Sun’s damaging
ultraviolet rays.
Structures of the Skin (cont.)
The dermis is the thick layer of skin
beneath the epidermis that gives skin
strength, nourishment, and flexibility.
The dermis contains sweat glands, blood
vessels, nerves, hair follicles, and
muscles.
Structures of the Skin (cont.)
The fatty layer is the innermost layer of
skin which insulates the body, acts as
protective padding, and stores energy.
How do the skin’s three
layers differ?
Skin Injuries and Repair
• A bruise is an injury where blood
vessels in the skin are broken, but the
skin is not cut or opened.
• The broken blood vessels release
blood into the surrounding tissue.
Skin Injuries and Repair (cont.)
• When you break one or more layers of
skin, it is called a cut.
• The released blood of a cut will usually
thicken and form a scab over the cut
which prevents dirt and other outside
substances from entering the body.
• Skin heals by producing new skin cells
that eventually repair the cut.
Skin Injuries and Repair (cont.)
• A burn is an injury to skin caused by
contact with hot objects, extremely cold
objects, chemicals, radiation,
electricity, or friction.
• Burns are classified by the depth of
damage to the skin as first-degree,
second-degree, or third-degree burns.
Healthy Skin
Protecting skin from the ultraviolet rays in
sunlight and eating a balanced diet are
two ways to help keep skin healthy.
The Skin and Homeostasis
• Skin helps maintain homeostasis in
several ways.
• Skin can make vitamin D and protect
the body from outside substances,
which helps regulate the body’s
internal environment.
The Skin and Homeostasis (cont.)
• Skin and the circulatory system help
cool the body when it becomes
overheated.
• If the body becomes cold, blood
vessels constrict and reduce thermal
energy loss.
The skin, the nervous system, and the
muscular system work together to
maintain homeostasis.
The Skin and Homeostasis (cont.)
How does the skin interact
with other body systems to
help maintain homeostasis?
The integumentary system contains all
the external coverings of the body.
• The epidermis is the outermost layer of
skin.
• The dermis is the layer of skin that
contains sweat glands, blood vessels,
nerves, hair follicles, and muscles.
What is the name of the pigment
that protects the body by
absorbing some of the Sun’s
ultraviolet rays?
A. sweat
C. melanin
B. vitamin D
D. skin
A bruise is the result of breaking
which of these?
A. epidermis
B. blood vessel
C. dermis
D. scab
What is the name of the thick layer of
skin beneath the epidermis that gives
skin strength, nourishment, and
flexibility?
A. melanin
B. fatty layer
C. integumentary system
D. dermis
Do you agree or disagree?
5. Skin helps regulate body temperature.
6. Skin is made of two layers of tissue.
Key Concept Summary
Interactive Concept Map 1
Interactive Concept Map 2
Interactive Concept Map 3
Chapter Review
Standardized Test Practice
The skeletal system,
the muscular system,
and the skin interact
with each other to
maintain homeostasis
by moving, supporting,
and protecting the
body.
Lesson 1: The Skeletal System
• The skeletal system supports the body, helps it
move, and protects internal organs. Bones store fat
and calcium and make red blood cells.
• Bones are protected by cartilage and are connected
to other bones by ligaments at joints.
• The skeletal system works
with the muscular system
and the skin to protect and
support the body and enable
it to move.
Lesson 2: The Muscular System
• Muscles support and stabilize the skeleton, enable
bones and organs to move, protect the body, and
regulate temperature.
• You can consciously control skeletal, or voluntary
muscles. You cannot consciously control involuntary
muscles, which include the cardiac muscle that
pumps blood and the smooth muscles that move
food and blood.
• The muscular
system interacts
with other body
systems to protect,
support, and move
the body.
Lesson 3: The Skin
• The skin protects the body, regulates temperature,
contains receptors that respond to stimuli, makes
vitamin D, and helps eliminate waste.
• The skin has three layers. The epidermis is the
outermost layer. The dermis is below, and the fat
layer is the inner layer. The epidermis produces
melanin, which protects the body from ultraviolet
rays.
• The skin works together
with the skeletal and
muscular systems to
protect and support
the body.
What kind of bone tissue contains
small holes that make it less
dense than compact bone tissue?
A. cartilage
B. red bone marrow
C. spongy bone tissue
D. periosteum
Before birth the human skeleton is
made mostly of which of these?
A. bone
B. muscle
C. marrow
D. cartilage
What kind of muscle is the human
heart made of?
A. cardiac muscle
B. skeletal muscle
C. smooth muscle
D. voluntary muscle
Which of these attach muscles to
bones?
A. cardiac muscles
B. blood vessels
C. smooth muscles
D. tendons
Which term describes the
outermost layer of skin?
A. epidermis
B. dermis
C. fatty layer
D. melanin
What is the strong, flexible tissue
that covers the ends of bones?
A. compact bone tissue
B. spongy bone tissue
C. ligament
D. cartilage
What term describes the place
where two or more bones meet?
A. ligament
B. periosteum
C. joint
D. skeleton
Which of these work with
muscles to keep bones in place
when the body moves?
A. cartilage
B. joints
C. organs
D. tendons
Which system contains all the
external coverings of the body?
A. skeletal
B. integumentary
C. muscular
D. epidermis
Which of these contains sweat
glands and hair follicles?
A. epidermis
B. fatty layer
C. dermis
D. melanin