THE SKELETAL SYSTEM

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THE SKELETAL SYSTEM

• Chapter 14
• Lesson 1 part 1

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How do bones, muscles, and skin help maintain the
bodys homeostasis?
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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?

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Skeletal System Stats

• The human skeleton has about 206 separate bones.
• Bones account for approximately 1/5 of the bodys
  weight.
• Bones in your body are living organs that contain
  blood vessels, nerves, fat tissues, and
  blood-cell-forming tissues.

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Functions of the skeleton

• Support
• Movement
• Protection
• Storage
• Production

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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.

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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.

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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

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Storage

• calcium
• phosphorus

Minerals
Fat
When your body needs calcium, it is released from
bones into the blood.
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Production of Blood Cells

• bone marrow is involved in blood cell
  production

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• A bone is an organ composed of two types of
  living tissue compact and spongy.

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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.
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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.
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• 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.

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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.

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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
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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.
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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.
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Ligaments Tendons
ligaments - tough, flexible bands of connective
tissue that attach bones to other bones at joints
(joined to the periosteum)
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Ligaments Tendons
tendons - bands of connective tissue that connect
muscles to bones (joined to the periosteum)
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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

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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.

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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)
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Osteon
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Osteon
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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.
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Growth continues until adulthood, when most of
the cartilage has turned to bone.
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Bone fractures
fracture - the breaking of a bone or tissue
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Fractures are classified according to the cause
of the break the nature.
types of fractures cause traumatic fracture
spontaneous fracture nature
compound fracture simple fracture complete
incomplete comminuted greenstick impacted
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traumatic fracture
if break is caused by an injury
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spontaneous fracture
if break is caused by a disease
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compound fracture
if broken bone is exposed to the outside of the
body by a break in the skin
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Simple fracture
if the broken bone remains protected by uninjured
skin
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complete fracture
fracture line extends entirely through the bone
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incomplete fracture
fracture line extends partially through the bone
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comminutedfracture
bone is splintered
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greenstick fracture
one side of the bone is broken and other side is
bent
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Impactedfracture
one fragment is firmly forced into the other
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Repair of bone fractures
Unlike most body tissues, bone heals with its own
cells not those of scar tissue.
treatment is 2 fold 1)must be set in proper
alignment 2)immobilization