Lower Motor Neurons: Flaccid Paralysis Pt. 1

These flashcards cover key terminology and concepts related to lower motor neurons, motor systems, and the implications of cranial nerve lesions in movement control.

Lower Motor Neurons (LMN)

The direct connection between the central nervous system (CNS) and skeletal muscle, responsible for carrying motor commands.

Flaccid Paralysis

A condition resulting from the dysfunction of LMN, causing loss of muscle tone and weakness.

Pyramidal System

A motor pathway that conveys impulses for voluntary movement from the cerebral cortex to the lower motor neurons.

Basal Ganglia

A group of nuclei in the brain involved in coordinating movement and regulating posture.

Cerebellum

The brain region responsible for coordination and fine-tuning of movements.

Motor Unit

A functional entity consisting of an alpha motor neuron and the muscle fibers it innervates.

Gamma Motor Neurons

Neurons that innervate intrafusal fibers of muscle spindles, playing a key role in maintaining muscle tone.

Acetylcholine

The primary neurotransmitter at the neuromuscular junction, facilitating communication between neurons and muscles.

Mastication

The process of chewing that involves the muscles innervated by the trigeminal nerve.

Neuromuscular Junction (NMJ)

The synapse where a motor neuron communicates with a muscle fiber.

Oculomotor Nerve (CN III)

A cranial nerve responsible for innervating eye muscles, controlling movements like eye elevation and adduction.

Lesion of CN VI

Can lead to medial deviation of the eye due to paralysis of abduction.

Bell Palsy

A common condition affecting the facial nerve, resulting in weakness or paralysis of facial muscles.

Hypoglossal Nucleus (CN XII)

The motor nucleus responsible for tongue movement, located in the medulla.

Dysphagia

Difficulty swallowing, often associated with lesions in the nucleus ambiguus.

Ipsilateral

Referring to effects occurring on the same side as the lesion.

Contralateral

Referring to effects occurring on the opposite side of the lesion.

Equilibrium

The state of balance maintained by the vestibular receptors and cerebellum during movement.