Proprioceptors
Where are proprioceptors found?
Muscles, Tendons, and Joint Capsules
What do muscle spindles detect?
Gauge the amt of stretch of a muscle, and the Rate at which it changes in length. Play a key role in muscle tone.
What is balance achieved through? (2 things)
1. APAs: Anticipatory Postural Control
2. CPAs: Compensatory Postural Control
During quiet stance, and during small perturbations, movements at the ankle that act to restore a person‘s COM to a stable position.
Ankle Strategy
A point that corresponds to the center of the total body mass and is the point ar which the body is in perfect equilibrium.
COM
What are the proprioceptors in muscles called, and where in the muscle are they found?
What do GTOs detect?
The amount of pulling force placed on a tendon.
What 3 systems contribute to balance?
1. Visual
2. Vestibular
3. Somatosensory
The movement strategy used to control media lateral perturbations involving shifting the weight from side to side from one leg to the other. Hips are the key control point.
Weight- Shift Strategy
The vertical projection of the COM to the ground. Located slightly anterior to S2 in most individuals.
What are the proprioceptors that are located in the tendon of a muscle?
Golgi Tendon Organ
If a GTO senses too much tension occurring in the muscle tendon unit, it signals the muscle to _____.
Relax
Which balance system involves 3 semicircular canals and helps you understand/ process info about position/ movement of the head with respect to gravity and inertial forces?
Vestibular
This strategy is observed during balance tasks when a person quickly lowers their body COM by flexing the knees, causing associated flexion of the ankles and hips.
Suspension Strategy
The product of mass x velocity. The linear type refers to the velocity of the body along a straight path. Angular refers to the rotational velocity of the body.
Momentum
What are the 4 main types of recptors found in the joints capsules?
1. Ruffini
2. Pacini
3. Golgi
4. Unmyelinated free nerve endings
What do Ruffini Joint Receptors detect and when are they activated?
- Detect slow changes in the position of a joint
- Most sensitive with stretch at extreme Ranges
- Activated with the joint is in motion OR stationary
Which system gives info regarding the position of your head relative to the environment as well as speed and direction of head movement?
Visual
For rapid and/ or large external perturbations or for movements executed with the COG near the limits of stability, this strategy is used. Additionally, it uses rapid flexion/ext. at the hip to move the COM in the BOS.
Hip Strategy
The perimeter of the contact area between the body and its support surface; foot placement alters this and changes a persons postural stability.
BOS
What do golgi joint receptors detect?
Pressure and forceful joint motion into extremes of motion
What do pacinian Corpuscle joint receptors detect and when are they stimulated?
- Quick changes in pressure around a joint capsule
- Sensitive to Compression or changes in hydrostatic pressure
- Stimulated by changes in a joints position, and as they mov‘t ceases they are going to settle down and stop sending the messages
Which system gives info about where the body is in space with regard to its support surface? And includes both afferent and efferent info.
Somatosensory
If a large force displaces the COM beyond the limits of stability, a forward or backward step is used to enlarge the BOS and regain balance control.
Stepping Strategy
The sway boundaries in which and individual can maintain equilibrium without changing their BOS.
Limits of Stability