Effects of ageing on the neuromuscular system Flashcards
What three sources does the a-motorneurons (a-MN) receive neural input from?
- efferent (descending) neuron from the brain
- afferent (sensory) neurons from tissues
3.spinal neurons (including interneurons)
The premotor cortex helps coordinate what?
Sensory cues
The supplementary motor area helps provide?
programming the motor plan?
The primary motor cortex inites and executes what function?
Movement
The cerebral cortex helps with…
Planning and execution
The cerebellum provides…
coordination, precision, timing, processing of most sensory inputs
Basal ganglia helps…
intitiate and execute complex tasks
The hypothalamus helps…
initiate movement associated with feeding and drinking
The brainstem provides a minor role in…
coordinating movement
Muscle volume and cross sectional area as we age does what?
We see reductions
What tissue increases as we age?
Non-muscle tissue (fat and connective tissue)
Which muscle fibre type reduced with age the most?
Type 2 (fast twitch)
Muscle fibres see an accelerated loss after what age?
60
What underlying mechanisms cause muscle fibre reduction with age?
INactivity and immobilisation, changes in demands for force, velocity and duration
Loss of type 2 fibres with age can be attributed to two factors?
Sometimes its a reduction in area due to decreased number of fibres, and also due to a reduction in size of the fibres
We see a loss of ____ when we reach 60?
Alpha motor neurons (especially fast) from the spinal cord, with subsequent degeneration of their axons
How does nerve conduction velocity decrease with age?
Demyelinisation
Muscle contractility has two factors impacted with age which are?
An increase in peak tension and an increase in time to relaxation
How can force be adjusted?
Varying the firing rate (or stimulation frequency) of MU’s
What does “firing” refer to?
depolarisation of the neuron (impulse) and firing rate is measured in 1Hz
Which hormone increases with ageing
insulin
Which hormones decrease with age
Insulin sensitivity, growth hormone, IGF-I and testosterone
What diseases have an increased prevalence with ageing?
Parkinsons, Opthalmoplegic muscular dystrophy, essential tremor, huntingtons disease, dystonia, and myoclonus
