kinesthesia Flashcards
_____ is the perception of movement and position of limbs and other body parts such as jaw movements
Kinesthesia
_______ are specialized interoceptors that are used to transduce the initial kinesthetic information
Proprioceptors
compare type A, B, and C proprioceptors!
-Type A: fastest, largest, myelinated
-Type B: middle for speed and size
-Type C: smallest, slowest, unmyelinated
Explain the differences between the A subtypes (alpha, Ia, Ib, Aβ, Aγ)
-Aα → motor to skeletal muscle
-Ia → sensory to muscle spindles
-Ib → sensory to tendon organs
-Aβ → II → sensory for touch, pressure, muscle spindles
-Aγ → motor to intrafusal fibers
which of the proprioceptors are for motor?
Aα, Aγ
Type B proprioceptors transduce _____ information for PRE-ganglions
autonomic
what are the two types of C proprioceptors?
C, C(IV)
how do the different C proprioceptors differ in what they transduce?
-C: autonomic for post-ganglionic
-CIV: sensory for pain/temp
________ are on the outside of a muscle spindle while _________ are on the inside of a muscle spindle
Extrafusal muscle fibers, Intrafusal muscle fibers
Extrafusal muscle fibers are innervated by ___ neurons and intrafusal muscle fibers are inntervated by ______
- α motor neurons
- Group 1 and 2 (Aα, Aβ), Aγ
is there afferent sensory innervation of extrafusal muscle fibers?
NO!
______ wrap around the center of muscle fibers and
______ are near the end of muscle spindle fibers
Ia fiber,
II fibers
____ fibers carry stretch (static or tonic) and velocity (dynamic or phasic) sensation, while ___ fibers carry static only.
Ia, II
in which fibers does the Firing rate increases when muscle moves and decrease when muscle stops?
1a
in which fibers does the firing rate increases linearly as muscle rate increases with stretch ?
II
______ innervate extrafusal fibers, the highly contracting fibers that supply the muscle with its power while ________ innervate intrafusal fibers, which contract only slightly.
alpha motor neurons
Gamma motor neurons
______ is when a skeletal muscle contracts involuntarily when suddenly stretched by an external force (passive stretch)
Stretch (myotatic) reflex:
which motor neurons fire in response to Ia input in a stretch reflex?
alpha
a stretch reflex is considered ______ because only one neuron-neuron synapse exists in the arc
monosynaptic
does a stretch reflex have interneurons?
no
understand the arc of a stretch reflex
When muscle ______, muscle spindle gets lax
contracts
______ activate to contract spindle and take up the slack
Gamma motor neurons
what is gamma bias? what controls it?
gamma bias is the gain of the response to stretch, gamma motor neurons
To prevent muscles from opposing each other,______ motor neurons of the opposing muscle are inhibited by the same ___ signal
alpha, 1a
_______senses muscle force
golgi tendon organ
The _________ prevents muscle and tendon tears from too much force
Golgi tendon reflex
explain the golgi tendon reflex
- Ib afferent from muscle → CNS
- Ib inhibitory interneuron → IPSP to flexor muscle (ex: bicep)
- Separate EPSP to extensor muscle to bring back flexor muscle from edge (ex: tricep)
muscle spindles in parallel sense _____, GTO in serial sense ________
muscle length, muscle force
what does the dorsal column pathway/medial lemniscal pathway sense?
Light touch, proprioception, vibration
what are the three neurons for the lower body portion of the dorsal column pathway?
- 1st order neuron = dorsal root ganglia
-Feeds into the dorsal horn of spinal cord and transcends up
PNS - 2nd order neuron = gracile nucleus
-CNS - 3rd order neuron = ventral posterior lateral (VPL)
-In the thalamus (CNS)
what are the three neurons for the upper body portion of the dorsal column pathway?
1st order neuron = Dorsal root ganglion
2nd order neuron = Cuneate nucleus
3rd order neuron = ventral posterior lateral (VPL)
After the 2nd order neuron for both upper and lower body, _______ occurs, then it goes to VPL
crossing over (decussation)
what is the non-head internal proprioception pathway and how does it compare to dorsal column?
Pretty much same as dorsal column pathway, except there is also the spinocerebellar pathway (for anything T1 and below)
T1 and below = DRG first synapses on________(in Clarke’s nucleus) then collaterals up spinocerebellar and dorsal column tract
spinocerebellar neuron
explain the pathway of the spinocerebellar pathway
- Signal comes from DRG
- Synapses on spinocerebellar tract neuron which goes up to cerebellum (cerebellum is in control of unconscious control of balance)
- It also relays to normal sensory nucleus (cuneatus and gracilis) so that it can go to thalamus and the brain knows what the rest of your body is doing
what are the neurons for the Trigeminothalamic pathway for the head?
- 1st order neuron = come in through trigeminal nerve, but bypass trigeminal ganglion, go to mesencephalic nucleus ***
- 2nd order neuron = principle nucleus of TG complex
- 3rd order neuron = ventral posterior medial (VPM)
- In thalamus
explain the jaw-closing reflex
- 1a receptors in muscle spindles in the masseter go through Masseteric n., → past trigeminal ganglion → to mesencephalic nucleus
- Collateral goes down to Motor nucleus of V → sends message out with Alpha motor neuron to masseter to contract and close
- Collateral goes up to VPM in brain to tell the brain what is going on
in the jaw opening reflex, the _____ is inhibited
temporal muscle
_____ is the state of tension that muscles are always in
Tone
_____ input from muscle spindle keeps the muscles in a state of readiness to resist stretch
Static fiber
Hypotonia is a decrease in muscle tone that results from loss of _____ or_______connection
alpha motor neuron, spindle afferent
_____ is an increase in muscle tone due to loss of modulation from brain centers
Hypertonia
