HES 202- Week 3 Golgi Tendon Organs and Joints & Vestibular System Pt. 1 Flashcards
Where are GTO’s located
In the tendon junction
GTO spindles are spread throughout the muscle belly and how do they lie
parallel
GTO’s lie in a… with muscle fibres
series
What type of afferent fibers innervate the GTO’s
1b afferent
GTO’s are bundles within a capsule and include what 2 things
1) nerve endings
2) collagen fibers
Nerve endings are____ among collagen fibers
interdigitate (which means interlocked)
What are the two roles of muscle spindle receptors
1) Sense muscle length
2) Sense muscle velocity
What are the 2 functions of the GTO receptors
1) muscle receptors that provide feedback to the CNS about muscle force/tension
2) primarily active muscle force/tension
The level of force neccessary to excite a GTO depends on…
mode of activation
How many newtons does a passive stretch require
2 newtons
how many millinewtons can an active contraction activate?
30-90 millinewtons
Are GTO’s much more sensitive to passive oractive generated forces
much more sensitive to actively generated forces
Are GTO’s sensitive to muscle contraction and what do they respond to
yes. They respond to increased muscle tension during a twitch
What is the function of the GTO?
Inhibit the agonist muscle. 2 Main functions: protective mechanism and modulate force
How doe GTO’s provide motor feedback?
feedback to spinal cord via 1b afferent
What is the autogenic inhibation
reflex that inhibits agonist motor neurons. It decreases Force Output
What are GTO’s sensitive to?
sensitive to muscle tension.
When are GTO’s activated
activated when muscle tension increases
Where are joint receptors located and where are they not found
Located within joint capsule, joint ligaments, and loose articular tissue. No receptors in cartilaginous surfaces of the joint or in synovial membranes.
What are the three main roles of joint receptors?
1) respond primarily at the limits of joint movement (extremes)
2) respond to joint pressure (joint swelling)
3) Joint receptors code ambiguously for joint movements (respond to both flexion and extension)
What do joint recptors cause on alpha motor neurons
cause weak and infrequent effects on alpha motor neurons
What neurons does the relfex activity happen on for joint receptors
reflex activity on alpha motor neurons
What needs to happen to the knee ligament before EMG activity can be detected
knee ligaments must be heavily stretched before an detection from EMG
What do the semicircular canals care about and what are the three parts to them
They deal with head rotation and there is the anterior, posterior, and horizontal
What do the Otolith organs care about and what are the two parts
care about linear motion and 2 parts are utricle and saccule
What is the function of hair cells (mechanoreceptors)
transform mechanical energy into neural activity
What are the 2 parts of the hair cell
Kinocillium (apex of the hair cell)
Stereocillium (linked stair-like structure)
What happens when stereocillia are pushed towards the kinocillium
hair cells depolarize
What happens when stereocillia are pushed away from the kinocillium
hair cells depolarize
what do mechanorecpetors (stereocilia and kinocilium respond to
respond to acceleration of gravity that is in line with hair cells
What does the semi-circular canal detect
angular acceleration
What is the canal filled with
filled with fluid (endolymph(
What is the cupula
house hair cells in the crista
What does acceleration lead to?
leads to increased firing rates, while deceleration leads to hyperpolarization (decreased firing) in the 8th nerve afferent
What happens during periods of constant velocity
the hair cells return to normal leakiness and the 8th nerve afferent return to baseline firing rates
What are the three angular accelometers in the semicircular canal
anterior SCC, Posterior SCC, and horizontal SCC
What does balance between left and right excitation and inhibation
leads to sensation of head rotation
What does head rotation causes in terms of endolymph
causes opposite endolymph fluid movement
What does the opposite endolymph fluid movement cause
causes stereocilia to be pushed towards kinocilium in the left semicircular canal = excitation and the opposite response in the right semicircular canal = inhibition
What are the semi-circular canals
Capula surrounded by endolymph (fluid)
What is the otlithic membrane
gel-like substance
What does the otoliths organs detect
detects linear acceleration
What do the utricle detect
horizontal linear acceleration
What does Saccule detect
vertical linear acceleration
What causes the cilia to move
the shearing of the membrane
What happens when the head tilts or accelerates
gravity causes the otoliths to slide, pulling the stereocillia and causing the hair cell to depolarize
What are otoliths sensitive to
sensitive to linear acceleration
