Musculoskeletal Reflexes Flashcards
(40 cards)
Dorsal white matter
Contains ascending tracts to the cortex of the brain
Lateral white matter
Ascending and Descending corticospinal tracts
Primarily pathway of cerebellum receiving and sending signals
Anteriorlateral
Ascending and Descending tracts that modulate pain, temperature and maintain muscular posture.
Lamina 1
Found in dorsal horn
Dorsal root fibers that mediate pain, touch and temperature
Lamina 2
Found in dorsal horn
Substantia gelatinous neurons that modulate pain, muscular activity and temperature.
Lamina 3 and 4
Found in dorsal horn
Contains Proper sensory nucleus and spinothalamic tracts
Receives information from lamina 2 and mediates temperature, pain and crude touch.
Lamina 5
Found in dorsal horn
Receives descending tracts from corticospinal and rubrospinal areas.
Site of corticospinal tract development
Receives proprioception fibers and regulates movement
Lamina 6
Found in dorsal horn
Lateral portion: Receives descending corticospinal and rubospinal fibers
Medial portion: receives Afferent from muscle spindles and joint Afferents
receives majority of proprioception fibers and regulation of movement
*ONLY present in cervical and lumbar segments for limb modulation
Jaw muscle stretch reflex includes what nerve and what segmental innervation?
Pons= segmental innervation
Mandibular and trigeminal branches = Nerves
Biceps muscle stretch reflex includes what segmental innervation and what nerve?
C5-6 = segmental innervation
Musculocutaneous = nerve
Brachioradialis muscle stretch reflex includes what segmental innervation and what nerve?
C5-6 = segmental Innervation
Radial = nerve
Triceps brachi deep muscle reflex includes what segmental innervation and nerve?
C7-8 = segmental innervation
Radial = nerve
Finger muscle stretch reflex includes what segmental innervation and nerve?
C8 and T1 = segmental innervation
Median = nerve
Knee muscle stretch reflex includes what segmental innervation and nerve?
L3-4 = segmental innervation
Femoral = nerve
Ankle muscle stretch reflex includes what segmental innervation and nerve?
S1-2 = segmental innervation
Tibial = nerve
Upper abdominal superficial reflex includes what nerves and center modalities?
Afferent nerve center and efferent nerve = T7-10
Lower abdominal superficial reflexes includes what nerves and center modalities?
Afferent and efferent nerves and center = T10-12
Cremasteric superficial reflex includes what nerves and center modalities?
Afferent nerve = femoral
Efferent nerve = genital branch of genital femoral
Center = L1
Plantar superficial reflex includes what nerve and center modalities?
Afferent nerve = tibial
Efferent nerve = tibial
Center = S1-2
Perineal (anal wink) superficial reflexes include what nerve and center modalities?
Afferent nerve = pudendal
Center = S4-S5
Efferent nerve = pudendal
Ventral horn somatotopic organization of neuron bodies.
Posterior section of ventral horn = flexors
Anterior section of ventral horn = extensors
Medial section of ventral horn = axial and limb girdle
Lateral section of ventral horn = distal extremities.
Alpha vs gamma motor neurons
Alpha: large A type motor neurons that synapse on extrafusal fibers (bulk of muscle not muscle spindle)
- receive input from upper motor neurons and muscle spindles
- generate contractile force
Gamma: small A type motor neurons that synapse on intrafusal fibers (muscle spindle in the middle of the muscle belly)
- receive input from upper motor neurons
- control basic muscle tone and reset sensitivity of a muscle
Lateral inhibition explanation
Three steps
- alpha motor neuron is excited
- alpha motor neuron stimulates renshaw cells and other neurons (if present) via cholinergic signals
- Stimulated renshaw cells inhibit motor neurons via GABA
Renshaw cells
Regulate firing of alpha motor neurons “sharpen the signal”