THE SKELETAL SYSTEM
Chapter 14
Lesson 1 part 1
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?
Skeletal System Stats …
The human skeleton has about 206
separate bones.
Bones account for approximately 1/5 of the
body’s weight.
Bones in your body are living organs that
contain blood vessels, nerves, fat tissues,
and blood-cell-forming tissues.
Functions of the skeleton
Support
Movement
Protection
Storage
Production
Support
The skeletal
system serves as a
framework for the
support of the
body.
Bones provide support
that helps you sit up,
stand, and move your
body.
Movement
The skeletal system
and the muscular
system work
together and move
your body.
Bones serve as
levers and with
the muscular
system produce
movement.
Bones in your skeleton protect
soft fragile tissue and internal
organs like the spinal cord, heart,
and lungs.
Cranium {skull} –
brain (eyes, inner ears)
ribs - heart and lungs
vertebrae - spinal cord
Storage
Minerals:
Fat
calcium
phosphorus
When your body needs calcium, it is
released from bones into the blood.
Production of
Blood Cells
bone marrow
is involved in
blood cell
production
A bone is an organ composed of two types
of living tissue: compact and spongy.
Structure of Bones
The bone's surface is
covered with a layer
of dense, white,
fibrous tissue called
the periosteum.
The periosteum
is responsible for
muscle attachment
and for bone growth
and repair.
periosteum
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
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.
Red Bone Marrow
Red bone marrow a soft tissue that
produces blood
cells; located in the
marrow cavity of
long bones and in
the spaces of spongy
bone
Red Bone Marrow
In young people this cavity is filled mostly
with red bone marrow, a soft tissue that
produces red blood cells and certain other
blood cells. Makes approximately a billion
new blood cells everyday.
Yellow Bone Marrow
Yellow bone marrow
stores fat and is found
inside the longest part
of long bones.
It gradually replaces
the red bone marrow
as people grow older.
Ligaments & Tendons
ligaments tough, flexible
bands of
connective
tissue that
attach bones to
other bones at
joints (joined to
the periosteum)
Ligaments & Tendons
tendons - bands of
connective tissue
that connect
muscles to bones
(joined to the
periosteum)
two main types of tissue
make up the skeleton
Bone - consists of living bone
cells and the non-living material
they secrete
Cartilage - a flexible supporting
tissue blood vessels never pass
through cartilage
Cartilage
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.
Osteon
(Haversian system)
a unit of bone
tissue; composed
of a central canal
which housed a
blood vessel,
osteocytes (bone
cells) and matrix
(layers of nonliving
material around it)
Osteon
Osteon
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.