Control Of Muscle Movememt Flashcards
What is muscle movement?
Motor movement- which is controlled by the nervous system which activates motor Neurons
Activated motor neurons triggers contraction of all the skeletal fibers within its motor unit
What are the three classifications of motor activity ?
Reflex
Voluntrary
Rhythmic
Which are overlapping classes of somatic response responses
What are the main differences between the three types?
The difference in their complexity and in the nervous system level to which they are integrated
What are somatic reflex responses?
They are automatic responses brought about by the skeletal muscle contraction that takes place without conscious effort
They are the least complex type of purposeful movement.
They include protective and postural reflexes
What are some examples of protective and postural n reflexes?
Protective- withdrawing from painful stimulus + coughing
Postural - maintain the desired position of head, trunk,limbs and stabilise our balance against gravity and other external forces as we stand and move - examples include the stretch reflex- which is the simplest reflect- involves involuntary contraction to passive stretching of a muscle. And the more complex- vestibular reflexes- which bring body and head in proper alignment when a person gets put off balance.
What is vestibular reflexes
How are postural reflexes excited/activated ?
In response to I put from the flowing sources:
1- proprioreceptors in the muscles and joints that provide info regarding the relative position and move movement of the body and its different parts
2- the vestibular apparatus- in the inner ear which detects changes in position and motion of head
3- tough receptors- tough receptors that monitor pressure on skin from integration with environment (such as the ground)
4- the eyes, which provide visual input about body position with relation to surroundings.
Where can some somatic reflexes be integrated?
In spinal cord- spinal reflexes ie withdrawal reflex
Or at brain stem level - cranial reflexes ie vestibular reflexes
Most s relfexes can be modulated by conscious input from cerebral cortex.
What are voluntary movements?
Most complex type of motor activity
They are goal directed movements initiated and terminated at will
Are integrated by cerebral cortex
Examples range from simple acts - picking up a cup
To highly skilled movement ie gymnastics or playing musical instrument.
We can have unconscious postural adjustments which are integrated with voluntary motor tasks.
What are Unconscious postural adjustments?
We can have unconscious postural adjustments which are integrated with voluntary motor tasks.
With repetitive practice, learned voluntary movements like dance can become almost reflex like
The learned actions get stores as procedural memory in the cerebellum- their execution can be brought forth by unconscious brain levels without deli berate thought of each manoeuvre- muscle memory
What is muscle memory?
Is the term applied to having the body unconsciously reproduce a memorised voluntary motor routine.
What are rhythmic activities ?
Stereotypical movements repeated in a general pattern ie walking and chewing
The cerebral Cortex consciously starts/stops rhythmic activities but the details of their execution are accomplished in a reflex like fashion by lower CNS without conscious effort
What is an example of rhythmic activity ? Explanation
Whereby networks of specific interconnected excitatory and inhibitory interneurones and their associated motor neurons in the spinal cord function as central pattern generators
Once activated the CPG autonomously bring about rhythmic patterned outputs ie walking by commanding precisely timed alternate contraction/relaxation of multiple muscles of leg.
This occurs in a cyclical, coordinated fashion to accomplish repetitive stepping movements
Output from these intrinsic oscillatory networks can be modulated by higher motor areas in cortex, ie such as if you decide ti pick up your walking speed
What influences motor neuron output?
Multiple neural inputs influence motor neuron output
Control of any movement, regardless of its level of complexity, depends on converging input to motor neuron of specific motor units.
There are 3 types of input to motor neurons to controll output to muscle fibers
What are the three levels of input given to motor Neurons that control their output to the muscle fibres they innervate ?
1- input from afferent Neurons
2- input from the primary motor cortex
3- input from the brain
