The Muscular System
&
The Skeletal System
&
Skin
CRCT Coach Book:
Pages 72-75
• For humans and most
other animals, movement
is important for survival.
• Being able to move
makes it possible to
escape danger, get food,
and to find a mate.
• Movement is made
possible by the skeletal
and muscular systems.
The Skeletal System:
Purpose:
• supports the body and
allows movement.
• It also protects internal organs,
stores some materials, and makes
blood cells
2 Parts:
1. Axial: Skull &
vertebral column
2. Appendicular:
appendages
(arms, legs, hips &
shoulders)
Major Organs:
• 206 bones (in humans)
• cartilage
• Did you know??
Bones
Bones are living tissues that make up the
skeleton.
• Bones support the body.
• They are made up of bone cells
surrounded by deposits of calcium and
other minerals.
• A typical bone is surrounded by a
tough layer of connective tissue.
• As blood passes through this layer, it
supplies oxygen and nutrients to the
bone
Blood Marrow
• Inside bones are cavities that contain a soft
tissue called bone marrow.
• Yellow marrow is made up
mostly of fat cells.
• Red marrow produces red blood cells, some
kinds of white blood cells, and platelets.
Cartilage
• The skeleton of a developing fetus begins as
cartilage.
• Cartilage is a flexible connective tissue.
• As the body develops, most of the cartilage in the
body is replaced by bone.
• Some parts of the body where cartilage is not
replaced by bone include the lower part of the
nose and the connective tissue that forms your
ears.
Cartilage continued…
• Cartilage also remains at joints, the places where
two bones meet.
• This cartilage helps cushion the joints.
• Many long bones, such as those in the arms and
legs, have growth plates at their ends. At these
plates, cartilage grows, making the bones longer.
• After a while, the new cartilage is replaced by
bone. By early adulthood, the cartilage in the
growth plates is replaced by bone. When this
happens, the person stops growing.
Joints
• A joint is a place where one bone attaches to
another.
• Tough fibers called ligaments connect bones to
each other at joints.
Types of Joints
• There are three main types of joints:
1. Immovable or fixed joint
2. Slightly movable joint
3. Freely moveable joints
• Each type of joint is described by the type of
movement it allows.
Immovable Joints
• An immovable joint, or fixed joint, does not
allow movement.
• At this type of joint, the bones are locked
together by connective tissue or fused
together.
• The bones in the skull meet at immovable
joints.
Slightly Movable Joints
• Slightly movable joints allow restricted
movement.
• The joints between adjacent vertebrae that
protect the spinal cord are examples of
slightly movable joints.
Freely Movable Joints
• Freely movable joints
allow movement in one
or more directions.
• The four common types
of freely movable joints
are:
1. Ball and Socket
Joint
2. Hinge Joint
3. Pivot Joint
4. Saddle Joint
The Muscular System
Purpose:
• The muscular system
consists of the body’s
muscles.
• One job of the muscular
system is to work with the
skeletal system to move the
body.
• It also helps to:
 keep the body warm
give the body shape
provide the force needed
to move blood
throughout the body.
• There are about 600 muscles in the human
body!!
• Two Main types:
– Involuntary: you can not control them
– Voluntary: you can control them
Types of Muscle
• There are three basic types of muscle tissue in
the human body:
1. skeletal muscle
2. smooth muscle
3. cardiac muscle
•
Each type of muscle tissue plays a different
role.
Skeletal Muscle
• Muscle tissue that connects
to the bones.
• Most skeletal muscles are consciously controlled
by the central nervous system.
• These muscles are used for such movements as
kicking a ball, lifting a fork, or turning the pages of
a book.
• Skeletal muscles look striped because they have
bands called striations. For this reason, skeletal
muscle is also called striated muscle.
Smooth Muscle
• A type of muscle that is usually not under your
conscious, voluntary control.
• The stomach and the walls of veins are made up
mostly of smooth muscle tissue.
• Smooth muscles do such things as moving food
through the digestive tract.
• Smooth muscle cells
are not striated.
Cardiac Muscle
• Cardiac muscle tissue makes up the
heart.
– only in the heart.
– Recall that the heart is a muscular organ
that pumps blood through the circulatory
system.
• Cardiac muscle is striated,
like skeletal muscle.
• However, cardiac muscle is not under
your conscious or voluntary control. In
this way, cardiac muscle is more like
smooth muscle.
Bones and Muscles:
Working Together
• Skeletal muscles are attached to the
bones of the skeleton by strips of
connective tissue called tendons.
• The muscles are attached to bones in
opposing pairs.
– When one muscle contracts, or tightens,
it pulls the bone in one direction.
– The other muscle in the pair relaxes.
– To return the bone it its original position,
the second muscle contracts, pulling the
bone in the opposite direction, as the
first muscle relaxes.
SKIN
• Skin is the largest organ in the human body.
• Spread out, it covers 1.5 meters squared!
• Functions:
1. Protection
2. Maintain temperature
3. Eliminate wastes
4. Gather information
5. Produce vitamin D
2 Layers:
• Epidermis
• Dermis
• Under the skin is a
layer of fat
Epidermis
• Top layer
• Mostly dead skin cells
• Protects the under
layers
• Thinner than the
dermis
• No nerves or blood
vessels
Does contain melaninpigment that gives skin
it’s color
Dermis
• Thicker, underneath layer
• Contains:
– Blood vessels
– Nerves
– Sweat glands
– Oil glands
– Hair follicles