Flashcards in Module 7 (Ch. 17) Deck (128):
What is a neuron?
Cell specialized to carry electrical signal
What is a nerve impulse?
Electrical signal carried by neurons
What are the 3 components of a neuron?
What carries nerve impulse toward cell body?
What carries nerve impulse away from cell body?
What are afferent neurons?
What is an integrative neuron?
Integrates/processes the sensory stimuli received from sensory neurons
What are efferent neurons?
[Gray/White] matter is on the outside of the cerebrum.
[Gray/White] matter is on the inside of the cerebrum.
What are isolated clusters of gray matter found within white matter called?
Nuclei or ganglia
Why is white matter white?
What does myelin do?
Sheaths axons and helps speed conduction of nerve impulses
Where do connections and processing occur in the brain?
Gray matter of cerebrum (then sent to the white matter to carry signals to distant sites)
The inside of the spinal cord is [gray/white] and the outside is [gray/white]
Where do connections occur in the spinal cord?
Inner gray matter
What are white matter tracts of the spinal cord composed of?
Ascending pathways - sensory information
Descending pathways - motor information
How many pairs of spinal nerves are there?
How many pairs of cranial nerves are there?
Can peripheral nerves contain both sensory and motor neurons?
While some are one or the other, some nerves are mixed
Where does voluntary motor control originate?
Cerebral cortex (outer portion of the cerebrum)
What is an upper motor neuron?
Motor neuron that travels down in a descending white matter tract of the spinal cord
What is a reflex arc?
Pathway of a reflex has an arc-like shape
What is the purpose of a reflex?
Automatic responses to protect from danger (specifically children)
How can we modify a reflex?
Descending connections from the brain to the reflex arc via UMN can increase response of a reflex or inhibit it
What is a learned/patterned behavior?
Activity that is learned and so well patterned that it is carried out in what appears to be a "reflexive" manner
After so many repetitions, can perform activity without conscious thought (like driving)
What is neural facilitation?
How all associations are made and why learned behaviors become so rooted in the nervous system
Functionally - responses reinforced through repetition and intensity
Structurally - physical changes to pathways of neurons that lower thresholds
What is the problem with neural facilitation in terms of a tight muscle?
If relationship of muscle tightening is not addressed, pattern of muscle tightening from certain stimuli becomes entrenched; triggering stimulus can tighten muscle more easily next time.
How is neural facilitation used in physical therapy?
Working with the nervous system, helping clients to unlearn pattern of response and relearn a new and healthier pattern of response.
Facilitating good technique is crucial in PT.
What is the Feldenkrais technique?
movement therapy that seeks to create client awareness of their movements including their faulty patterns of movement
What is reciprocal inhibition?
Neurologic reflex that causes antagonist to a joint action to relax when the mover is directed to contract.
Nervous system sends both facilitatory impulses to the LMN that control the mover and inhibitory impulses to the LMN that control the antagonist
How can reciprocal inhibition be used to palpate muscles?
If need to palpate a muscle that contracts with others, perform a function that inhibits the surrounding muscles.
Ex: palpating brachialis - flex forearm while pronated to activate brachialis but inhibit biceps
How can reciprocal inhibition be used to stretch muscles?
Have client contract mover muscle and inhibit the antagonist, which allows a deeper stretch of the antagonist.
What is proprioception?
Ability of the nervous system to know the body's position in space and the body's movement through space.
What are mechanoreceptors?
Sensory receptor cells sensitive to mechanical pressure stimuli
What are the 3 categories of proprioceptors
What are the 2 major types of fascial/joint proprioceptors?
Muscle proprioceptors create proprioceptive reflexes in order to
protect muscles and tendons from injury
What are the 2 major types of muscle proprioceptors?
Golgi tendon organs
Proprioceptive sensation from the inner ear (both static and dynamic) is often referred to as the sense of...
Where are inner ear static proprioceptors for head position located?
In vestibule of inner ear
Where are inner ear dynamic proprioceptors for movement located?
Semicircular canals of inner ear
What other receptors can provide proprioceptive function besides mechanoreceptors?
Vision, pain, touch
Why do you have to close your eyes during a field sobriety test?
Alcohol decreases proprioception, but you can use your eyes to help make up for that loss
How does pain work proprioceptively?
Draws attention to that body part
What are the 2 deep (and major) mechanoreceptors of touch?
(Also joint proprioceptors)
What are the 4 superficial mechanoreceptors of touch?
Krause's end bulbs
Free nerve endings
Where are joint proprioceptors?
Within dense fascia, in and around joint capsules, in deep muscular fascia
What are joint proprioceptors?
Mechanoreceptors in and around capsules of joints
When a joint is compressed on one side, it is ______ on the other
What are interstitial myofascial receptors?
A 3rd group of mechanoreceptors (aside from Pacini's corpuscles and Ruffini's endings) found within joint capsules. Believed to be involved in pain reception and proprioception.
What is the main difference between Pacini's corpuscles and Ruffini's endings?
How quickly they adapt to the application of mechanical force.
Pacini's = quick
Ruffini's = slow
Pacini's corpuscles are sensitive to and stimulated only by changes in ______
[Due to quick adaptation to mechanical force]
Ruffini's endings are sensitive to and stimulated by ______
changes in joint position (movement) AND static position of the joint
[Due to slow adaptation to mechanical force; even when joint stops moving, it keeps firing to the CNS]
What are examples of pressure reflexes (when pressure is applied to fascial/joint proprioceptors)?
Increase in circulation of blood to local area
Decrease in tone of muscles in local area
Decrease in sympathetic NS output
What is a muscle spindle?
Muscle proprioceptor located within a muscle that is sensitive to stretch (lengthening of muscle - amount and speed)
Where are muscle spindle cells?
Within the belly of the muscle and parallel to the fibers
What muscles have the greatest proportion of muscle spindles?
Suboccipital group of the neck
Intertransversarii and rotatores of the spine
How are muscle spindles similar to muscle cells?
They are contractile
Spindles are considered intrafusal while muscle cells are considered extrafusal
What happens when a muscle is stretched and sends this sensory impulse to the CNS?
A reflex contraction of the muscle occurs - prevents excessive stretching that might tear the muscle.
Why should stretches be done in a slow and gentle manner?
Due to the muscle spindle stretch reflex; hard or fast stretches will result in tightening and potential injury
What is the muscle spindle reflex also called?
What is are gamma motor neurons?
UMNs and LMNs that set the sensitivity of muscle spindles
[Contracts intrafusal fibers]
What are alpha motor neurons?
UMNs and LMNs that control muscle contraction
[Contracts extrafusal fibers]
Muscle spindles are more sensitive when they are [taut/relaxed]
Sensitivity of muscle spindles is set by UMNs based on what 3 factors?
Previous and present physical traumas to the region
Need for stability in the region
General emotional and physical stress levels
What regions of the brain primarily influence and control gamma UMNs?
What other purpose do muscle spindles have outside of protection from injury?
Increase the strength of a muscle contraction immediately after it has been quickly stretched - reasons for backswings in sports
Used in plyometric training
What sets muscle resting tone?
Gamma motor system - sets the sensitivity of spindles
What is muscle facilitation?
Tone of muscle spindles (and therefore muscle itself) is set high
What is muscle inhibition?
Tone of muscle spindles (and therefore muscle itself) is set low
Positive to muscle facilitation?
Poised to respond to any stimulus and contract more quickly - important in sports
Negative to muscle facilitation?
Muscle may tighten easily
Positive to muscle inhibition?
Muscle more relaxed, less tight
Negative to muscle inhibition?
Less able to respond to stimuli and tighten quickly and efficiently
Should a muscle be more facilitated or inhibited?
Need to find a balance depending on the situation.
What are muscles that tend to be overly facilitated?
What are muscles that tend to be overly inhibited?
What does "locked short" mean?
Facilitated muscles that shorten and tighten
What does "locked long" mean?
Inhibited muscles that are lengthened out by locked short muscles, and are tight
Why should bodyworkers know the difference between trigger points and global tightening of a muscle?
Trigger points require direct, local work; whereas global tightening is a CNS issue and requires working on the sensitivity setting of the muscle spindles.
Where does muscle memory reside?
What is upper crossed syndrome?
Tight upper trap and levator scap
Weak deep neck flexors
Weak rhomboids/serratus anterior
What is lower crossed syndrome?
Weak glute max
Tight erector spinae
What is a golgi tendon organ?
Muscle proprioceptor located within a tendon of a muscle; sensitive to a pulling force placed on tendon (typically when muscle contracts)_
What are golgi end organs?
Golgi receptors located in joint capsules and ligaments
What is the Golgi tendon organ reflex (tendon reflex; inverse myotactic reflex)?
Reflex relaxation to prevent tearing of the tendon
Which reflex is used as part of E-stim?
Golgi tendon organ reflex - causes muscle to contract and sustained for 5-10 minutes which triggers the reflex and relaxes the muscle
How does the Golgi tendon organ reflex help in stretching?
Asking client to contract against resistance, and then relax, allows therapist to stretch the muscle further
Called contract-relax stretching
OR post-isometric relaxation stretching
OR proprioceptive neuromuscular facilitation
What are the macula of the inner ear?
Provide proprioception info to the brain about the static position of the head
What are the crista ampullaris of the inner ear?
Provide proprioception info to the brain about movement of the head
Information from inner ear (labyrinthine) proprioceptors, as well as sense of hearing from cochlea, travel in which nerve?
CN VIII (vestibulocochlear nerve)
How many maculae are in the vestibule?
What is a macula made of?
Gelatinous substance with hair cells that attach to sensory neurons, and otoliths
What are otoliths?
Crystals in the gel of a macula that increase its weight, making it more responsive to changes in position
How are impulses generated by the macula?
Position of the head causes otoliths to fall with gravity, which causes the hairs to bend and stimulate the sensory neurons
How many crista ampullaris structures are in the semicircular canals?
3 (1 in each canal)
What plane do the semicircular canals reside in?
1 canal resides in each cardinal plane (sagittal, frontal, transverse)
What is a semicircular canal?
Fluid-filled canal with an expanded end called the ampulla (where the crista ampullaris is located)
What is the crista ampullaris?
Structure with hair cells attached to sensory neurons
How do the crista ampullaris provide dynamic proprioception?
When head moves, fluid is set in motion in 1 or more canal; this bends the hair cells
What is the righting reflex?
Whenever head becomes unlevel, righting reflex directs muscles of body to alter position of the joints to bring head back to level position
What is dizziness?
Proprioceptive confusion; when a disagreement exists between what the various proprioceptors of the body report regarding the position and/or movement of the head
How does the brain know about trunk posture?
Joint and muscular proprioceptors of the neck (whether its straight or bent)
How do neck injuries (whiplash, etc) cause dizziness?
Incorrect proprioceptive signals may be sent from the neck to the brain, which contradict other signals (like from the eyes) - this causes proprioceptive confusion --> dizziness
What is the flexor withdrawal reflex?
Flexion withdrawal movement of a body part when that part experiences pain (meant for protection from injury)
Note: reciprocal inhibition occurs in the extensors
What is the crossed extensor reflex?
This works with the flexor withdrawal reflex; as body part flexes and withdraws, extensor muscles of the contralateral extremity contract into extension (meant to create balanced posture)
Note: reciprocal inhibition occurs in flexors of contralateral extremity
What is the tonic neck reflex?
Contraction of the arm muscles based on change in position of the neck (e.g., neck rotates to the right, right arm extends and left arm flexes)
Note: reciprocal inhibition occurs in left flexors and right extensors in that scenario
What is the purpose of the tonic neck reflex?
Orient the body in the direction which the head is oriented
What is the purpose of the righting reflex?
To keep us upright in a balanced position
What is the (labyrinthine) righting reflex?
If inner ear perceives posture might lead to falling, information is sent to the brain and then the spinal cord to contract muscles to keep us upright
Ex: during a back dive, the backward bend of the neck causes reflex contraction of trunk and arm flexors (athletes have to override this)
What is a hypnic jerk?
A sudden and strong muscular twitch when falling asleep
Theory is that when muscles relax, sudden change in joint position is perceived as falling and body is ordered to contract to stop the fall
What is the cutaneous reflex?
Relaxation in musculature after massage or heat
What is the pain-spasm-pain cycle?
Vicious cycle of pain causing muscular spasm, which causes further pain, which causes further spasming, and so forth
What is muscle splinting?
Muscle spasm caused by the nervous system to keep an injured area from moving so it can heal
What is body armoring?
When a person armors the body by splinting/spasming muscles in a region of the body for emotional or psychologic reasons (ex: broken heart --> chest tightening)
As muscle spasming continues, pain increases because of what 2 factors?
1. Strong pull of contraction on attachments at rest as well, increased with movement
2. Compromised blood flow (closed venous return of blood to heart - waste products contain acidic substances that irritate nerves; if artery is blocked, body cells deprived of nutrients)
What is it called when a muscle spasm is so strong that it blocks off arterial blood supply?
How can trainers help stop the pain-spasm-pain cycle?
Guide client through exercises that will gradually stretch and loosen the musculature and facilitate venous return of blood; exercise can also release endorphins
What are endorphins?
Morphine produced within the body
How can bodyworkers help stop the pain-spasm-pain cycle?
Soft tissue techniques such as massage and stretching to relax the musculature; massage and range of motion techniques that focus on increasing venous circulation
What is the gate theory?
Proposes a gating mechanism (in spinal cord) is present in the nervous system that blocks the perception of pain when faster signals of movement or pressure occur at the same time.
Movement and/or pressure sensations can close the gate and prevent transmission of pain signals.
(pain is carried in slow unmyelinated neurons)
What senses are carried by slow neurons? fast neurons?
Slow = pain
Fast = movement, pressure
Why does a person shake or squeeze a hand when it is cut or burned?
Gate theory - shaking causes movement signals and squeezing causes pressure signals to enter the brain at the same time as the pain; because they are faster than pain signals, they can block the sensation of pain
How does gate theory explain fight or flight?
When involved in a potentially dangerous situation, being distracted by pain would hamper our ability to fight or take flight
Why is it that you often don't realize that you overdid it in a workout until hours later or the next day?
Gate theory - movement and pressure from the workout blocked pain signals.
How do topical balms containing menthol, oil of wintergreen, and eucalyptus use the gate theory?
They irritate the skin and distract the body from pain (counterirritant theory)