Topic 4 - Movement Analysis

List out the components in a motor unit

Answer explanation

Dendrite

Cell body

Nucleus

Axon

Motor end plate

Synapse

Muscle

Dendrites role is to...

• contained within the spinal cord or in clusters just outside it called ganglia.

• link the neuron to other neurons and allow information to flow between different nerves.

•  membrane-bound structure found in the cell body of the neuron.

• is the main component of nerve signal transmission.

The Axon carries electrical impulses away from the ____ ____ to other neurons and muscle fibres.

Answer explanation

The axon carries electrical impulses away from the cell body to other neurons and muscle fibres.

Calcium gates are open - calcium ions are then rushed into the synaptic end bulb to push the sacs of AcH towards the surface of the synaptic end bulb.

What is this process called?

• Muscle movement

• Motor Neuron Impulses

• Cholinesterase

• Depolarisation

What is the role of Acetylcholine (AcH)

• To catalyze and promote the breakdown of a neurotransmitter called acetylcholine.

• To open receptors on the muscle cells, triggering the process of contraction.

•  To diffuse across the space and bind to receptors in the membrane of the sarcolemma.

What is the primary function of Cholinesterase?

• Primary function is to promote the use of a neurotransmitter called acetylcholine.

• Primary function is to increase the amount of sodium ions in the synapse bulbs.

• Primary function is to catalyze and promote the breakdown of a neurotransmitter called acetylcholine.

Myosin – a protein molecule found in thick filament.  Has a tail and 2 heads (cross bridges) which move back and forth. Produce a ratchet like power stroke.

• True

• False

Actin – the major component of the thick filament. A double strand of actin subunits which are strung together like beads. Each individual ‘bead’ of actin has a myosin binding site.

• True

• False

What is Tropomyosin function?

• Twists around the actin. When the sarcomere is not shortening, the position of the tropomyosin covers the binding sites on the actin sub units and prevents the cross bridges from binding.

• Twists around the myosin. When the sarcomere is not shortening, the position of the tropomyosin covers the binding sites on the myosin sub units and prevents the cross bridges from binding.

Troponin – found periodically along the tropomyosin strand.  Moves the tropomyosin aside and exposes the binding sites. This can only occur in the presence of _______.

Answer explanation

Troponin – found periodically along the tropomyosin strand.  Moves the tropomyosin aside and exposes the binding sites. This can only occur in the presence of calcium.