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Module 4
Responding to the
environment
2.4.7 Coordinated movement
Learning Objectives
 To understand how
movement is coordinated
Success Criteria
 Identify parts of a joint
(Grade E - D)
 Describe how coordinated movement
requires action of skeletal muscle
about joints, with reference to the
elbow joint
(Grade C –B)
 Compare and contrast synapses and
neuromuscular junction
(Grade B – A)
Starter
 Describe the differences between the CNS and the
peripheral nervous system
(4 marks)
Coordinated movement
 CNS coordinates muscle movement, receives sensory info.
and decides what responses is required. If a response is
needed, the CNS sends impulses along the motor
neurones to let the skeletal muscles contract.
 Skeletal muscles are attached to bones by tendons.
Ligaments attach bones to other bones, to hold them
together. The structure of joints between bones
determines movement
1. Ball and socket – allow movement in all directions
2. Gliding joints – wide range of movement
3. Hinge joints – movement in one plane only – elbow.
The elbow is an example of a synovial joint. Synovial
fluid is a lubricant, to ease this movement.
Antagonistic muscles
The best-known example of antagonistic muscles
are the biceps and triceps muscles, which
articulate the elbow joint. Movement of bones at
many joints require a range of actions and is
under control of groups of muscles called
synergists
Muscles cannot push, only pull  work in pairs which
oppose each other. Muscles must be attached to
incompressible skeleton, which they move.
Control of contraction
6
Neuromuscular Junction
1. Impulse from motor neurone causes ACh
vesicles to be released into the gap
2. ACh binds to sarcolemma (muscle fibre
membrane)
3. Depolarisation travels down tubules
4. Calcium ions released from sarcoplasmic
reticulum
5. Calcium ions bind to proteins in muscles
causing contraction
6. Acetylcholinesterase breaks down ACh in
gap and stops the contraction
Plenary - Compare and Contrast
Neuromuscular Junction & Synapse
Similarities
Differences
Neuromuscular Junction
Synapse
Compare and Contrast
Neuromuscular Junction & Synapse
Similarities
•Neurotransmitter in
vesicles
•Vesicles release
neurotransmitter into cleft
•Neurotransmitter
diffuses across gap &
binds to receptor
•Neurotransmitter results
in depolarisation
•Enzymes degrade
neurotransmitter
Differences
Neuromuscular Junction
Synapse
•Neurone to sarcomere
•Neurone to neurone
•Postsynaptic simulation •Postsynaptic simulation
leads to depolarisation of leads to AP in
sarcolemma
postsynaptic neurone
•End plate has
appearance of microvilli
•Synaptic knob is smooth
and rounded
Learning Objectives
 To understand how
movement is coordinated
Success Criteria
 Identify parts of a joint
(Grade E - D)
 Describe how coordinated movement
requires action of skeletal muscle
about joints, with reference to the
elbow joint
(Grade C –B)
 Compare and contrast synapses and
neuromuscular junction
(Grade B – A)