22 Questions
What is the role of alpha motor neurons and their axons in the central nervous system?
To connect the CNS to skeletal muscle contraction units
What is the term for the loss of muscle bulk due to damage to the nervous system?
Neurogenic atrophy
What is the term for quick twitches of muscle fibers of a single motor unit that are visible on the surface of the skin?
Fasciculations
What is the term for spontaneous contraction of a single muscle fiber?
Fibrillations
What is the term for abnormally low resistance to passive stretch?
Hypotonia
What is the term for lack of resistance to passive stretch?
Flaccidity
What primarily characterizes a lower motor neuron lesion (LMNL)?
Damage to anterior horn cells or motor fibers in the brainstem or spinal cord
Which structures are responsible for fine-tuning the coordination of movement during its execution?
Cerebellum and muscle receptors
Where do the cell bodies of lower motor neurons typically reside?
Spinal cord or brainstem
Which type of neurons send impulses to lower motor neurons to exert control?
Upper motor neurons
Which type of motor neurons have their origin in the cerebral cortex and brainstem?
Upper motor neurons
Which anatomical station is affected in a lower motor neuron lesion involving the anterior horn cell (AHC)?
Anterior horn cell of the spinal cord's grey matter
Which type of neuron is responsible for transmitting impulses from the cerebral cortex to synapse with lower motor neurons?
Upper motor neuron
What role do muscle receptors play in the execution of movement?
They record stretch and send information to LMNs and cerebellum
What is the primary role of lower motor neurons?
To convey signals to extrafusal and intrafusal skeletal muscle fibers
Which of the following describes the axons of alpha motor neurons?
Large cell bodies and large, myelinated axons
How do the axons of alpha motor neurons affect skeletal muscles?
They project to extrafusal skeletal muscle, causing contraction
Where are the cell bodies of alpha and gamma motor neurons located?
Ventral horn of the spinal cord
What function do gamma motor neurons primarily serve in skeletal muscle?
Increasing tension on muscle spindle receptors
Which muscle fiber type is most numerous and involved in muscle contraction?
Extrafusal muscle fibers
What distinguishes gamma motor neurons from alpha motor neurons concerning their innervation?
Gamma motor neurons innervate intrafusal fibers
What is the relationship between motor nuclei of cranial nerves and lower motor neurons?
Both form cell bodies of lower motor neurons for cranial nerves
Learn about lower motor neuron lesions, their signs, and how to differentiate between upper and lower motor neuron lesions. Understand the pyramidal system and its role in transmitting cortical commands.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
