Conducted by: Brenan, Jay and Satoro
AIMS:
* Demonstrate how vibration induces illusions of movement * To determine whether vibration has had any effect on ability to match joint angle between left and right arms * Observe the effect of fatigue on ability to sense force.
INTRODUCTION
Proprioception is defined as the sense of the relative position of neighboring parts of the body. It is the ability to distinguish how ones body is situated, either in motion or stationary within space. Proprioception is like a third sensory modality that supplies feedback to the solely on the status of the body internally, the first two senses being interoceptive and exteroceptive. The proprioceptive ability that one possesses is the sense that specifies whether the body is moving at the required effort , as well as other body parts are positioned in relation to each other. The ability to estimate weight of an object, the force and time at which our muscles must be contracted are examples of our proprioceptive ability.
Examples of proprioceptors are muscle spindles also called stretch receptors and their associated 1a axons. These receptors make up the somatic sensory system that is focus on body sense or proprioception. The muscle spindle consists of several types of speacialized skeletal muscle fibers that are contained within a fibrous capsule. In the middle region of this fibrous capsule group 1a axons are wrapped around the muscle fibre on the spindle. Group 1a axons are the fastest and largest of the group 1 axons, which are also the thickest myelinated axons in the body.
When a weight is placed on a muscle , the muscle lengthen and the muscle spindles are stretched. The stretching causes of the spindle causes depolarization of the 1a axons endings, this is caused by mechanosensitve ion channels. The 1a axons enter the enter the spinal cord through the dorsal root, from here they branch repeatedly and then form synapsese on both