Lower Motor Neuron Lesion Overview

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What is the role of alpha motor neurons and their axons in the central nervous system?

To regulate autonomic functions such as heart rate and blood pressure

To transmit sensory information from the periphery to the CNS

To integrate cognitive functions such as attention and memory

To connect the CNS to skeletal muscle contraction units (correct)

What is the term for the loss of muscle bulk due to damage to the nervous system?

Muscle hypertrophy

Disuse atrophy

Neurogenic atrophy (correct)

Muscle dystrophy

What is the term for quick twitches of muscle fibers of a single motor unit that are visible on the surface of the skin?

Tetany

Fibrillations

Fasciculations (correct)

Muscle cramps

What is the term for spontaneous contraction of a single muscle fiber?

Fibrillations Signup and view all the answers

What is the term for abnormally low resistance to passive stretch?

Hypotonia Signup and view all the answers

What is the term for lack of resistance to passive stretch?

Flaccidity Signup and view all the answers

What primarily characterizes a lower motor neuron lesion (LMNL)?

Damage to anterior horn cells or motor fibers in the brainstem or spinal cord Signup and view all the answers

Which structures are responsible for fine-tuning the coordination of movement during its execution?

Cerebellum and muscle receptors Signup and view all the answers

Where do the cell bodies of lower motor neurons typically reside?

Spinal cord or brainstem Signup and view all the answers

Which type of neurons send impulses to lower motor neurons to exert control?

Upper motor neurons Signup and view all the answers

Which type of motor neurons have their origin in the cerebral cortex and brainstem?

Upper motor neurons Signup and view all the answers

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 Signup and view all the answers

Which type of neuron is responsible for transmitting impulses from the cerebral cortex to synapse with lower motor neurons?

Upper motor neuron Signup and view all the answers

What role do muscle receptors play in the execution of movement?

They record stretch and send information to LMNs and cerebellum Signup and view all the answers

What is the primary role of lower motor neurons?

To convey signals to extrafusal and intrafusal skeletal muscle fibers Signup and view all the answers

Which of the following describes the axons of alpha motor neurons?

Large cell bodies and large, myelinated axons Signup and view all the answers

How do the axons of alpha motor neurons affect skeletal muscles?

They project to extrafusal skeletal muscle, causing contraction Signup and view all the answers

Where are the cell bodies of alpha and gamma motor neurons located?

Ventral horn of the spinal cord Signup and view all the answers

What function do gamma motor neurons primarily serve in skeletal muscle?

Increasing tension on muscle spindle receptors Signup and view all the answers

Which muscle fiber type is most numerous and involved in muscle contraction?

Extrafusal muscle fibers Signup and view all the answers

What distinguishes gamma motor neurons from alpha motor neurons concerning their innervation?

Gamma motor neurons innervate intrafusal fibers Signup and view all the answers

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 Signup and view all the answers