Ch. 11 pg 290
The movement in humans involves bones,
ligaments, muscles, tendons and nerves.
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Provide anchorage for
muscles
Act as levers, changing
size and direction of
forces
Provide support for the
body and protection to
internal organs
Blood cell formation
Metabolism of calcium
and other minerals.
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Tough cords or sheets
of tissue
Connect bones together
Cover joints and
connections between
bones.
Flexible to allow
certain movement
Almost inelastic to
prevent movement
outside normal range
of a joint and prevent
dislocation
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Attach to bones and provide forces to change
position of bones and the body.
Work in antagonistic pairs
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Tough cords or straps of tissue
Connect muscles to bones
Help to anchor muscles to bone and to transmit
forces generated by contraction of muscles.
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These are the
points where
bones meet.
There are many
types of joints
according to their
movement, ex:
fixed, ball and
socket, pivot and
hinge joints.
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Cartilage: though, smooth
tissue that covers regions of
the bone. Prevents contact
between bones and absorbs
shocks.
Synovial lubricates the joint
and helps to prevent friction
Capsule: though ligamentous
covering to the joint. Seals the
joint, holds the synovial fluid
and prevents dislocation.
Biceps and triceps: muscles
connected to the humerus.
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Muscle used for
movement – skeletal
muscle.
Other types of muscle
are smooth and cardiac.
Striated muscle is
composed of bundles
and muscle fibres
A sarcolema surrounds
each muscle fibre
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Within each muscle
fibre, there are many
parallel elongated
structures called
myofibrils.
Between each myofibril
are large numbers of
mitochondria
Each muscle fibre
contains many nuclei
and a specialized E. R.
called sarcoplasmic
reticulum.
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Myofibrils consist of an
alternating series of light
and dark bands. In the
center of each light band
is a disk-shaped
structure called the Z
line. A part between one
Z line and the other is
called a sarcomere, the
functional unit of a
myofibril
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Two filaments compose
myofibrils: thin actin and
thick myosin filaments.
Actin filaments are attached
to the Z line.
Myosin filaments are
between actin filaments in
the center of the sarcomere.
One myosin filament is
surrounded by six actin
filaments.
Together they form cross
bridges during contraction
shortening the length of the
muscle fibre.
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During relaxation, a
regulatory protein
blocks the binding sites
on actin.
When a motor neuron
sends a signal to a
muscle fibre, the
sarcoplasmic reticulum
releases Ca+2 that cause
the regulatory protein
to move.
Myosin cross bridges
attach to the actin
myofilament.
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Energy stored in the
myosin head causes it
to move inwards
towards the center of
the sarcomere, moving
the actin filament a
small distance.
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ATP causes the
breaking of the crossbridges by attaching to
the myosin heads
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Hydrolysis of ATP
provides energy for the
myosin heads to move
away from the center of
the sarcomere (cocking
of the m. head)
The process continues
until the motor neuron
stops sending signals to
the muscle fibre.
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What is the role of ligaments in the elbow joint?
A.
Attach biceps to radius
B.Reduce friction between humerus, ulna and radius
C. Hold humerus, ulna and radius in proper alignment
D.Secrete synovial fluid
The diagram below shows part of a muscle fibre.
What parts are labelled I and II?
I
II
The unit between one Z-line and the next is
termed:
A.
B.
C.
D.
Sarcomere
Myofibril
Sarcoplasmic reticulum
Sarcolemma
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Distinguish between each of the following
word pairs:
Hinge joint and pivot joint
 Radius and humerus
 Hip and knee joint
 Actin and myosin
 ADP and ATP
 Ligament and tendon
 Extension and flexion
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THE END…