Review of proprio Flashcards
Proprioception
- 4 elements of information provided by muscles and joints
The body’s ability to sense movement, action, and location (closing the eyes and touching nose with index finger)
- direction, speed, amount, force of movement
Muscle afferents provide general and specific information about
the information is carried through (2)
muscle length and tension
dorsal root and anterolateral column
What is a muscle spindle
what do they respond to
it has both _____ and ____ innervation
a sensory receptor that lies parallel with an extrafusal fiber
stretching of a muscle
afferent and efferent
Afferent
sensory neurons that carry information to CNS (brain or spinal cord)
Efferent
carry motor information away from CNS (brain or spinal cord)
Specialized muscle fibers spindles are composed of
intrafusal
The 3 types of intrafusal muscle fibers
Each spindle contains how many intrafusal fibers
nuclear bag 1
nuclear bag 2
nuclear chain
2-12 (at least 2)
The central part of each intrafusal fiber is innervated
by a ______
aka
the central portion is composed of what type of tissue
sensory 1a primary ending, that wraps around each and every fiber
annulo- spiral fibers
noncontractile tissue
At the junction of the central part and the contractile
area, nuclear bag2 and chain fibers are also
innervated by
type 2 spindle endings
The endings of the intrafusal fibers are innervated by
gamma motor neurons
The 2 types of sensory endings
Primary (1a)
Secondary (2)
Where do secondary (type 2) SENsory endings innervate on the intrafusal fibers
on one or both sides of the primary endings (mainly inn nuclear chain fibers)
The motor supply innervates the _____ ends of the intrafusal fibers,
it is what type of neuron?
contractile
gamma motor
_ motor neruon innervates extrafusal fibers
Alpha
For motor output both ____ and ____ spindle endings make _____ excitatory connections to synergistic muscle
primary, secondary
polysynaptic
What is autogenic excitation?
%?
Primary spindle endings make monosynaptic connections to motor neuron cells innervating the same muscle to provide excitation to the muscle
greater than 70%
Efferent innervation of a spindle is called the
gamma system
Which gamma fibers innervate bag 1,2, and chain fibers?
gamma dynamic fibers innervate bag 1
gamma static fibers innervate bag 2 and chain
GTO
where does it lie and where is it located
what is it innervated by
golgi tendon organ
in series with muscle fibers, musculotendinous junction
1b sensory fiber
The overall purpose of the gamma system
maintain spindle sensitivity during muscle shortening
Functions of the GTO
- signal information about muscle tension
- inhibit muscle through 1b inhibitory interneuron
- excite antagonists through polysynaptic pathways
Small muscle receptors are innverated by
type 3 and 4 fibers
The GTO is only activated when ….
muscle contracts bc of how elastic it is
In order to avoid damage the GTO will …
shut down a muscle
