Chapter 13 Bones and Muscles
Section 1:
Organ Systems
and Homeostasis
What are the levels of organization in the body?
What systems are in the human body, and what are their
functions?
What is homeostasis?
Chapter 13 Bones and Muscles
Organs and Organ Systems
Each organ in your body is part of an organ system, which is
a group of organs that work together to perform a major
function.
Chapter 13 Bones and Muscles
The Epidermis
In some ways, the skin is the body’s largest organ.
Chapter 13 Bones and Muscles
Homeostasis
Despite the changes that are constantly happening outside your
body, the inside of your body is kept stable. This internal balance is
called homeostasis.
Some of the things that your organ systems keep a balance are:
•Temperature
•Blood water levels
•Blood pH (acidity of the blood)
•Salt, sugar, calcium and iron levels
•Blood pressure
•Sleep
An inability to maintain homeostasis
may lead to disease or even death.
Chapter 13 Bones and Muscles
End of Section:
Organ Systems
and Homeostasis
Chapter 13 Bones and Muscles
Section 2:
The Skeletal System
What are the functions of the skeleton?
What role do joints play in the body?
What are the characteristics of bone, and how can you
keep your bones strong and healthy?
Chapter 13 Bones and Muscles
What the Skeletal System Does
Your skeleton has five major
functions. It provides shape and
support, enables you to move,
protects your organs, produces
blood cells, and stores minerals
and other materials until your
body needs them.
Chapter 13 Bones and Muscles
Joints of the Skeleton
Movable joints are places in your skeleton where two or
more bones come together and allow movement.
Chapter 13 Bones and Muscles
Joints of the Skeleton
Moveable joints allow bones to move in 4 different ways.
Chapter 13 Bones and Muscles
Joints of the Skeleton
Ligaments are connective tissues found between 2 bones. It
is what holds these 2 bones together in the joint.
Chapter 13 Bones and Muscles
Joints of the Skeleton
Cartilage is another type of connective tissue, except it is not
found between the bones. It is found on the end of the
bone, and it helps protect the bones from damage as it
rubs against the other bone.
Chapter 13 Bones and Muscles
Joints of the Skeleton
Some of the joints in your body do NOT move. An example
of these immovable joints are the bones in your skull.
Infant Skull
Adult Skull
Chapter 13 Bones and Muscles
Bones—Strong and Living
Bones are complex living structures that undergo growth and
development.
Chapter 13 Bones and Muscles
Skeleton
Skeleton comes from a Greek
word meaning “a dried body”.
Skeletons are also used to
symbolize death.
The truth is, your skeleton is a
living, growing part of you, just
like your skin, muscles, and
other organs.
Chapter 13 Bones and Muscles
Spinal Column
The spinal column is the center
of your skeleton.
It provides the main support of
your skeleton. A person with a
“bad back” can not lift or move
much, no matter how strong
their muscles are.
It is made up of 26 small bones
called vertebrae.
The spinal column is also
known as the “backbone” or the
“vertebral column”.
Chapter 13 Bones and Muscles
End of Section:
The Skeletal System
Chapter 13 Bones and Muscles
Section 3:
The Muscular System
What types of muscles are found in the body?
Why do skeletal muscles work in groups?
Chapter 13 Bones and Muscles
Properties of Muscle
Muscle is made up of millions of tiny muscle fibers
that contract (shrink) and relax.
Chapter 13 Bones and Muscles
Properties of Muscle
Muscles can NOT stretch. They can only contract (shrink).
Chapter 13 Bones and Muscles
Types of Muscles
Your body has three types
of muscle tissue:
• skeletal muscle
• smooth muscle
• cardiac muscle
Chapter 13 Bones and Muscles
Skeletal Muscle
Skeletal muscles are the only type of muscle that your
conscious mind can control (voluntary muscle).
The cells in skeletal muscle have a banded (striated) look, so
they’re sometimes called striated muscle.
Chapter 13 Bones and Muscles
Skeletal Muscle
Skeletal muscles are paired together, and when one muscle
contracts, the opposite muscle must relax. As a result, it is
said that skeletal muscles work in pairs.
Chapter 13 Bones and Muscles
Skeletal Muscle
Tendons are strong connective tissues that attach skeletal
muscles to bone.
Chapter 13 Bones and Muscles
Smooth Muscle
Smooth muscle is found
inside most of your internal
organs, especially the
stomach.
Has a “smooth” texture,
which is where it gets its
name.
Is an involuntary muscle
(you can NOT control it).
Chapter 13 Bones and Muscles
Cardiac Muscle
Cardiac muscle is only
found in the heart.
Made up of striated muscle
(like skeletal muscle), but is
an involuntary muscle (like
smooth muscle)
Cardiac muscle cells are
full of mitochondria, which
is one reason why your
heart never gets tired.
Chapter 13 Bones and Muscles
End of Section:
The Muscular System
Chapter 13 Bones and Muscles
Section 4:
Machines and the Body
How are force and work related?
How does a lever make work easier?
How do bones and muscles function as levers in the
body?
Chapter 13 Bones and Muscles
Force and Work
Force: a push or pull of
an object
Work: the amount of
force you must use to
move an object a certain
distance
Work = Force x Distance
W=FxD
Chapter 13 Bones and Muscles
Force and Work
Sample Problem #1
You need to lift a 50 newton (N)
box a distance of 0.5 meters (m).
How much work will you perform?
Chapter 13 Bones and Muscles
Force and Work
Solution to Problem #1
Work = Force x Distance
W=FxD
Sample Problem #1
You need to lift a 50 newton (N)
box a distance of 0.5 meters (m).
How much work will you perform?
Force (F) = 50 N
Distance (D) = 0.5 m
W = 50 N x 0.5 m
Work = 25 N·m
Chapter 13 Bones and Muscles
Force and Work
Sample Problem #2
You need to lift a 65 newton (N)
box a distance of 2 meters (m).
How much work will you perform?
Chapter 13 Bones and Muscles
Force and Work
Solution to Problem #2
Work = Force x Distance
W=FxD
Sample Problem #2
You need to lift a 65 newton (N)
box a distance of 2 meters (m).
How much work will you perform?
Force (F) = 65 N
Distance (D) = 2 m
W = 65 N x 2 m
Work = 130 N·m
Chapter 13 Bones and Muscles
Levers
A lever is a simple machine that makes lifting heavy
objects easier.
Chapter 13 Bones and Muscles
Levers
A lever is a ridgid bar that is free to pivot (or rotate) on a fixed
point called a fulcrum.
Chapter 13 Bones and Muscles
3 Classes of Levers
Levers are classified according to the location of the fulcrum
relative to the input and output forces.
Chapter 13 Bones and Muscles
Real-Life Examples of the 3 Classes of Levers
First-Class Levers
Chapter 13 Bones and Muscles
Real-Life Examples of the 3 Classes of Levers
Second-Class Levers
Chapter 13 Bones and Muscles
Real-Life Examples of the 3 Classes of Levers
Third-Class Levers
Chapter 13 Bones and Muscles
Simple Machines in the Body
Most of the machines in your body are levers that consist of
bones and muscles.