Transcript Mechanic of Movement - Fulton County Schools

Mechanic of Movement
 Tissues
and Structures Involved
 Muscle
 Nerve
 Bone
 Cartilage
 What
are Tendons & Ligaments?
 Types of Joints
 Mechanics of Joints
Nerve and Muscle--the Motor Unit

Motor Unit is one
motor neuron plus the
muscle cells it
synapses

“Action potential”-controlled conduction
of electrical messages
in neurons and muscle
by depolarization of cell
membrane
Neuro-Muscular Junction
Action potential in nerves triggers
chemical release at synapse which
triggers action potential in muscle
Bone and Cartilage

Bone as tissue

Bones as structures
formed from bone,
cartilage and other
tissues

Location of cartilage
in skeleton and
relation to joints
HOW DOES MOVEMENT
HAPPENS?
Muscles Pull on Tendons to Move
Bones at Connections called Joints or
Articulations
Tendons

Tendons are structures that connect bone to muscle,
muscle to muscle, or bone to bone

Made up of tendon
tissue (connective
tissue)

Can have various
shapes

Typical is cord-like
tendon of biceps
Frolich, Human Anatomy, Mechanics of Movement
Ligaments
 Ligaments
connect bone-tobone or reinforce
joints--they are
made up of
tendinous tissue
as well
Typical are knee
ligaments
Frolich, Human Anatomy, Mechanics of Movement

Joints or
Articulations
Connections
between bones

Usually, but not always allow for movement
 Formed from various connective tissues




Functions of joints



Fibrous
Cartilaginous
Synovial (most complex--typical limb joints)
Hold bones together
Allow for mobility
Ways joints are classified


Functionally
Structurally
Frolich, Human Anatomy, Mechanics of Movement
Functional Classification
The amount of movement the joint allows
Synarthroses
immovable joints
Amphiarthroses
slightly moveable joints
Diarthroses
freely moveable joints
Frolich, Human Anatomy, Mechanics of Movement
Structural Classification
Fibrous joints
Generally immovable
Fibrous tissue separate the boney region at the joint
Cartilaginous joints
Immovable or slightly moveable
Cartilage separates the boney regions at the joint
Synovial joints
Freely moveable
The boney regions of the joint are separated by a
space
Frolich, Human Anatomy, Mechanics of Movement
Fibrous Joints
Bones united by fibrous tissue –
synarthrosis or largely immovable.
 Skull
 Bones tightly bound
by minimal fiber
 Syndesmoses
 Longer connecting
fibers
 Joint has more give
Frolich, Human Anatomy, Mechanics of Movement
Cartilaginous Joints
Mostly amphiarthrosis
Bones connected by cartilage
Pubic symphysis
Intervertebral joints
Hyaline cartilage
unites bones
Epiphyseal growth
plates
Costal cartilagesternum
Frolich, Human Anatomy, Mechanics of Movement
Synovial Joints
Diarthroses – movable joint
Most common joint in the body
 Articulating ends of bones are
covered with hyaline cartilage
 Enclosed by a capsule of fibrous
connective tissue lined with synovial
membranes
 Joint cavity is filled with synovial
fluid for lubrication
 Ligaments reinforce the joint
Frolich, Human Anatomy, Mechanics of Movement
Typical Synovial Joint
Frolich, Human Anatomy, Mechanics of Movement
Structures Associated with the
Synovial Joints
Bursae – flattened fibrous sacs
Lined with synovial membranes
Filled with synovial fluid
Not actually part of the joint
Tendon sheath
Elongated bursa that wraps
around a tendon
Types of Synovial
Joints
The type of joint, in part, determines the range
and direction of movement
Types of Synovial
Joints
The type of joint, in part, determines the range
and direction of movement
HOW DOES MOVEMENT HAPPEN?
The elbow joint - a hinge joint allowing movement in 1 plane
Upper arm
bone humerus
The Capsule. Holds the bones of the
joint in place.
Capsule (ligaments)
Synovial membrane
Cartilage
Cartilage
Synovial
fluid
tendon
Triceps
muscle
The synovial membrane.
Secretes synovial fluid
The synovial fluid. Lubricates the
movement of the cartilage surfaces
against each other – reducing
friction and preventing arthritis
(inflammation and joint damage).
Cartilage. Lubricates the movement of
the cartilage surfaces against each
other – reducing friction and preventing
arthritis (inflammation and joint
damage).
HOW DOES MOVEMENT
HAPPEN?
The elbow joint - how the bicep and triceps
control
When the biceps contracts
movement
humerus
the elbow joint flexes (its joint
angle decreases).
biceps (flexor
When the triceps contracts
muscle), contracts
the elbow joint extends (its
joint angle increases).
Triceps
(extensor)
The biceps and triceps are
relaxes
called antagonistic muscles
because they have the
radius
opposite effect on the same
ulna
joint.
THE BICEPS AND TRICEPS ARE
AN ANTAGONISTIC PAIR
Remember that for this to
work properly the biceps must
relax when the triceps
contracts, and vice versa.
Inflammatory Conditions
Associated with Joints
Bursitis – inflammation of a bursa usually
caused by a blow or friction
Tendonitis – inflammation of tendon sheaths
Arthritis – inflammatory or degenerative
diseases of joints
Over 100 different types
The most widespread crippling disease in the
United States
Clinical Forms of Arthritis
Osteoarthritis
Most common chronic arthritis
Probably related to normal aging processes
Rheumatoid arthritis
An autoimmune disease – the immune system
attacks the joints
Symptoms begin with bilateral inflammation of
certain joints
Often leads to deformities
Frolich, Human Anatomy, Mechanics of Movement
X-ray of hand affected by
arthritis
Frolich, Human Anatomy, Mechanics of Movement
Frolich, Human Anatomy, Mechanics of Movement
Artificial Hip Joint
Frolich, Human Anatomy, Mechanics of Movement
Lots of problems
with joints result
from sports
injuries
Click on the picture for the
web sports injury clinic
What can go wrong with joints
Dislocation The bones move
Tendons strain or tear
Making movement of the joint
painful and difficult
out of position, causing pain and
preventing joint movement
Cartilage damage
Antagonistic muscle
damage due to too
overloading Making
movement of the joint
painful and difficult
Movement becomes painful
or impossible and the joint
becomes inflamed.