Download The Skeletal System

How did the biceps and triceps
change as you bent and
straightened your arm?
When the arm was extended,
the biceps would relax
(lengthen) and the triceps
would contract (shorten). The
reverse happen when the arm
is bent.
How do the skeletal muscles
cause bones to move?
Muscles are attached to
bones by tendons. The
muscles work in pairs and
pull against the bone to cause
movement.
What did your finding about the
thickness of the upper arm
suggest about how muscles
work?
The thickness of the arm
stayed the same. Muscles
must work in pairs. While one
contracts, the opposing
muscle must relax.
The Skeletal
System
The Skeletal System
• Is made up of:
– bones
– cartilage
– tendons
– ligaments
– joints
Number of Bones
• Infant or baby
– 305 bones
• Adult
– 206 bones
– Bones in the skull, pelvis, spine, and long
bones fuse
Skeleton Formation
• As a fetus, your skeleton starts out as
cartilage
– Connective tissue that is stronger than
bone
• As you grow, the cartilage is replaced
by bone
• Your ears and nose tip remain cartilage
Functions of the Skeletal System
•
•
•
•
•
Provides shape and support
Enables you to move
Protects your internal organs
Produces blood cells
Stores certain materials until your body
needs them like calcium.
Bone Characteristics
• Bone is alive
– Full of blood vessels
– Contains nerves (pain if broken)
• Bone is made mainly of 2 minerals
– Calcium
– Phosphorous
• Bone grows and changes all the time
Spongy Bone
Compact Bone
Periosteum
Bone Marrow
Growth Plate
Bone Marrow
• Bone marrow is located in the hollow
cavity inside of some bones
– Red
• Produces blood cells
– Yellow
• Fat and energy reserve
Joints of the Body
Body systems that work with
the skeletal system;
• The skeletal system needs blood
flow and produced red blood cells
for the circulatory system, needs
minerals from the digestive
system and requires the muscular
system for movement
Which cell part is like the
skeletal system?
microtubules
The Muscular
System
• There are
approximately 600
muscles in your
body
Involuntary Muscles
• muscles not under conscious control
– You don’t have to think about them
• breathing, digesting, sneezing, heart beating
Voluntary Muscles
• muscles under conscious control
– smiling, walking, running, typing etc…
Parts of the Muscular System
• skeletal muscle
• smooth muscle
• cardiac muscle
Skeletal Muscle
• muscles attached to
bones
• voluntary
• striated (striped)
• muscle that reacts
quickly and tires
quickly
Skeletal Muscle
Smooth Muscle
• found inside most
blood vessels and
organs
• involuntary
• not striated (striped)
• reacts slowly and tires
slowly
Smooth Muscle
Cardiac Muscle
• found only in the
heart
• involuntary
• striated (striped)
• does not get tired
Cardiac Muscle
Functions of the Muscular
System
• Allows the body to move
• Aids in circulation and
digestion (circulatory and
digestive system)
Tendons and ligaments help
to attach muscles to the
skeletal system so that they
can work together.
Tendon
• Strong connective tissue that attaches
muscle to bone
Ligament
• Bands of connective tissue connecting one
bone to another bone
Body systems that work with
the muscular system;
• The muscles need food from the
digestive system and oxygen from
the respiratory system delivered
by the circulatory system. They
also depend on the circulatory
and excretory system to remove
waste products and the skeletal
system to allow movement