The Skeletal System
How the Skeletal System
Works
The skeletal system consists of bones and
connective tissue.
206 bones
Bones of the skeleton range from the
tiniest bone of the inner ear (about
0.25 cm long) to the longest bone of
your thigh (femur)
Connective tissues cushion the
bones, attach bone to bone, and
attach bone to muscles
Your skeletal system has many functions,
including:
providing support for the body
protecting internal tissues and organs from damage
acting as a framework for attached muscles
allowing movement of limbs and igits
producing new red and white blood cells
storing fat and minerals, such as calcium and phosphorus
Bones
Living tissues formed into different layers
Outer layer is hard, densely packed,
compact bone
Beneath spongy bone, less dense with a
network of cavities filled with red bone
marrow, where blood cells are produced
Some bones contain yellow bone marrow,
type of connective tissue that stores fat
Bone Structure
Humerus bone – Long bone
Wrist bone – short bone
Rib bone – Flat bone
Connective Tissue
Three types of connective tissue:
Cartilage – strong, flexible act as a cushion between
two bones to reduce friction, also act as a flexible
structure for soft parts of the body (tip of the nose or
outer ear)
All bones begin in the embryo as cartilage, early in
development the cartilage hardens
Ossification process by which bone is formed,
renewed, and repaired
Ligament is a band of fibrous, slightly elastic
connective tissue that attaches one bone to another,
attach to bones to create joints: attaches the two
bones of the forearm to each other, forming the pivot
joint
Tendon is fibrous cord that attaches muscle to the
bone, muscles contract to move parts of the body.
Cartilage surrounding the knee
ossification
ligament
tendons
Joints – points at which bones meet
some joints do not move (bones of the skull); flexible joints include balland socket, hinge joints, pivot joints, and ellipsoidal joints.
Ball and
socket joint
Hinge joint
Pivot joint
Understanding Skeletal Problems
Injuries and disorders harm the skeletal system
Poor nutrition, infections, sports injuries, and
poor posture, degenerative disorders can also be
problems
Compound fractures – broken end of the bone
breaks through the skin
Simple fracture broken bones doen not break
through the skin
Hairline fracture – parts of the bone do not
separate
Transverse fractures when the fracture is
completely across the bone
Comminuted fracture when the bone shatters inot
more than two pieces
compound
hairline
Transverse fracture
Comminuted fracture
Injuries to joints can occur from
overuse strain or disease
Dislocation – bone slips out of place, tearing the
ligaments that attach the bone at the joint (reset joint
and immobilize until healed)
Torn cartilage – sharp blow to a joint or a severe
twisting of a joint, (surgery removes pieces of the
damaged cartilage)
Bursitis – painful inflammation of bursa (fluid-filled
sac) that helps reduce friction in the joints
Bunions – painful swellings of the bursae in the first
joints of big toes ( wearing ill-fitting shoes make
bunions worse, larger ones require surgery)
Arthritis - inflammation of a joint, from injury, natural
wear and tear or autoimmune disease ( immune
system mistakenly attacks itself, targeting the cells,
tissue and organs of own body)
Torn cartilage
Dislocation knee cap
Bursitis
Bunions
Arthritis
Repetitive Motion Injury
Prolonged, repeated movements
(sewing or computer work)
Carpal tunnel syndrome – ligaments
and tendons in the wrist swell
(numbness, a tingling sensation in
thumb and forefinger, pain and
weakness in hand
Osteoporosis – progressive loss of
bone tissue