What is an alpha motor neuron and what is its function?
alpha motor neurons are lower motor neurons whose cell bodies are found in the anterior horn of the spinal cordand whose axons travel down to the body to innervate skeletal muscle to cause muscle contraction.
Are alpha motor neurons cholinergic?
Taken together, these findings indicate that α-MNs are uniquely vulnerable among cholinergic neuron populations in the SMA mouse spinal cord, with γ-MNs and other cholinergic neuronal populations being largely spared.
What are alpha motor neurons quizlet?
Alpha motor neurons. Lower motor neurons that innervate extrafusal fibers in skeletal muscle; when these neurons fire, skeletal muscle fibers contract.
What is the difference between alpha and gamma motor neurons?
Alpha motor neurons control muscle contraction involved in voluntary movement, whereas gamma motor neurons control muscle contraction in response to external forces acting on the muscle.
What is the role of interneurons?
As the name suggests, interneurons are the ones in between – they connect spinal motor and sensory neurons. As well as transferring signals between sensory and motor neurons, interneurons can also communicate with each other, forming circuits of various complexity. They are multipolar, just like motor neurons.
Where are alpha motor neurons?
The α-motor neurons are the largest neurons in the spinal cord, with myelinated axons that exit the spinal cord through the ventral roots and travel in peripheral nerves to innervate muscles.
What are alpha motor neurons innervated by?
Like other neurons, α-MNs send axonal projections to reach their target extrafusal muscle fibers via axon guidance, a process regulated in part by neurotrophic factors released by target muscle fibers. Neurotrophic factors also ensure that each muscle fiber is innervated by the appropriate number of α-MNs.
What do alpha motor neurons do?
Alpha motor neurons (also called lower motor neurons) innervate skeletal muscle and cause the muscle contractions that generate movement. Motor neurons release the neurotransmitter acetylcholine at a synapse called the neuromuscular junction.
What are Intrafusal fibers?
Intrafusal muscle fibers are skeletal muscle fibers that serve as specialized sensory organs (proprioceptors). They detect the amount and rate of change in length of a muscle. They constitute the muscle spindle, and are innervated by both sensory (afferent) and motor (efferent) fibers.