Exam 4 Flashcards
What are alpha motor neurons?
Neurons that send signals from the spinal cord to muscle fibers, directly triggering muscle contractions
What is a motor unit?
It’s a single alpha motor neuron and all the muscle fibers it controls (A coach and it players)
What is a motor neuron pool?
A group of alpha motor neurons that innervate a single muscle, collectively coordinating its movements (Lots of coaches for one player)
What are the major differences between slow and fast motor units?
Slow Motor Units contract slowly and are more useful for endurance purposes
Fast Motor Units contract quickly producing high force for brief periods
What is Excitation–Contraction Coupling?
It’s the process in which a muscle receives a signal to move and then actually does the movement.
What is the Sarcolemma?
The outer layer or “skin” of a muscle cell. (helps pass the signals into the muscle cell)
What are Myofibrils?
They are tiny fibers in a muscle cell that shorten when a muscle retracts (Made of sarcomeres)
What is the Sarcoplasmic Reticulum?
It’s a specialized form of the endoplasmic reticulum in muscle cells that stores and releases calcium ions
What are T-Tubles?
These are tunnel-like extensions of the sarcolemma that go deep into the muscle fiber. They help transmit electrical signals to all parts of the muscle fiber.
What is a sarcomere?
The sarcomere is the basic contractile unit of muscle.
What is the difference between thick and thin filaments?
Thick filaments: Made of Myosin, Pull the thin filaments to shorten the sarcomere
Thin filaments: Made of the actin, pulled in by the myosin head of the thick filament
What are muscle spindles?
These are sensory receptors within muscles that detect changes in muscle length.
What is proprioception?
This is the body’s ability to sense its position and movement in space.
What is the stretch reflex?
It is a reflex in which if you stretch a muscle too fast the muscle will automatically contract to counteract and prevent injury
What are gamma motor neurons?
These neurons control the sensitivity of muscle spindles. (They ensure that proprioceptive feedback is accurate during muscle contractions)
What is the Golgi Tendon Organ?
Located at the junction of muscles and tendons, they detect tension in the muscle and send signals to the brain when excessive force is detected to prevent muscle damage
What is Reciprocal Inhibition and how does it affect muscle coordination?
This is the process by which muscles on one side of a joint relax to allow muscles on the other side to contract.
What are Central Pattern Generators (CPGs)?
They are neural circuits within the spinal cord that produce rhythmic movements, like walking or breathing, without needing conscious thought.
What are the two main motor pathways?
The Lateral pathway and the Ventromedial pathway
What is the lateral pathway?
A group of nerve pathways in the spinal cord that help control precise, VOLUNTARY movements, especially in the distal areas of the body. (Feet and Hands)
What is the Ventromedial pathway?
Another set of spinal pathways, that controls posture and balance by affecting muscles closer to the body’s center, like those in the back and trunk. (Proximal/Axial)
What is the Corticospinal tract?
A spinal cord pathway that carries movement signals from the brain’s motor cortex to the spinal cord, helping control fine motor movements. (Lateral cortiospinal tract crosses at the medulla)
What is the Rubrospinal tract?
A pathway that starts in the red nucleus of the brain and helps with voluntary control of big muscles (Can act as a backup if the Corticospinal tract is injured)
What is the red nucleus?
A part of the brainstem that acts as a relay center for motor signals, especially those involving movement and coordination of the arms.
