NM - 10 Flashcards
(22 cards)
What is a motor unit and the difference between large and small motor units
Consists of a motor neuron and all of the muscle fibres it innervates
Motor units a that are large are greater than 100 muscle fibres eg postural muscles
Small are less than 10 fibres eg muscles requiring precise control
Ways you can increase muscle contraction (2)
By activating more motor unite ie recruitment
By Activating motor units more ie by increasing stimulus frequency to cause summation or tetanus
What is electromyography
Measures the electrical activity of skeletal muscle by placing electrodes in or near the muscle
Why would a clinician order an EMG
If a patient has signs or symptoms that may indicate a nerve or muscle disorder
What are slow muscles
Adapted for slow sustained , tonic and fatigue resistant contractions eg postural muscles
What are fast muscles
Adapted for rapid intense, phasic and easily fatigued contractions eg gastrocnemius
How are muscles characterised
Based on speed of contraction and ATP production
What is Type I
Slow oxidative
What IIa
Fast oxidative
what is type IIb
Fast - glycolytic
What’s does fast mean
higher Myosin ATPase activity
What does oxidative
ATP produced by oxidative phosphorylation
Much more efficient than glycolysis – more resistant to fatigue
what does glycolytic
generate ATP via anaerobic glycolysis (White Fibres) – Inefficient method which also produces lactic acid
What training do to muscle fibres
Improve oxidative capacity (more resistant to fatigue) * Increase blood supply/number of mitochondria
– Change muscle fibre diameter
* Size of muscle increased (hypertrophy) by short, high intensity,
anaerobic exercise (e.g. weight lifting) * Affects fast-glycolytic fibres
what is deneravtion
A lesion of the motor nerves to skeletal muscle
What is fasciculations
Visible twitching caused by release of Ach from degenerating motoneurons
Type I and II ATROPHY
occurs in peripheral neuropathies, disuse (bedrest, spaceflight, immobilization), myasthenia gravis etc.
Mainly type II atrophy with Duchenne muscular dystrophy and ageing
What is Type II hypertrophy
Occurs with weight training
Neuromuscular disease is due to … (3)
Neuropathy
Junctionopathy
Myopathy
what is neuropathy
disease affecting nerves) in the central or peripheral nervous system or both (peripheral nerves, e.g. motor neuron disease; multiple sclerosis etc.)
What is junctionopathy
(Neuromuscular junctions, e.g. myasthenia gravis)
What is myopathy
(disease affecting muscle, e.g. muscular dystrophies)
