Module 4 Laboratory Flashcards
– rapid, predictable, involuntary motor responses to stimulus
reflexes
include glandular and contraction of all three types of muscles
reflexes
mediate neural pathways
reflexarcs
initated by sensory receptors, which by having synaptic contacts within the spinal cord, are a basic level of regulation of muscles or glands
reflex movements
most basic of all reflexes, but other parts of the central nervous system also contain reflex pathways
spinal reflexes
affecting the body musculature in the control of balance
vestibulo-ocular reflexes
regulate the diameter of the pupil or degree of accommodation of the lens of the eye
autonomic reflexes
include the somatic nervous system and this reflex has been traditionally called spinal reflexes
somatic reflexes
also include the spinal cord
visceral reflexes
first part of reflex arc
somatic receptors
carry information from these receptors into the dorsal horn of the spinal cord
afferent nerve fibers
integrate information, which are lacking from some reflex arc
interneurons
carry motor impulses to the skeletal muscles
efferent nerve fibers
somatic effectors that carry out the response
skeletal muscles
- reflex arcs can be:
monosynaptic
polysynaptic
contain only two neurons (sensory and motor neuron)
monosynaptic
Patellar reflex and achilles reflex
‘
mono or polysynaptic?
monosynaptic
– multiple interneurons that interface between the sensory and motor neurons in the reflex pathway
polysynaptic reflex
– important diagnostic tool for assessing the condition of the nervous system
reflex testin
reflex testing grade
0 =
no response
reflex testing grade
1+ =
slight but definitely present
is reflex grade of 1+ normal?
may or may not be normal
reflex testing grade
2+=
brisk response
is 2+ normal?
yes
3+
very brisk response
is 3+ normal?
may or may not be normal
is 4+ normal
no
4+ means
repeating reflex (clonus)
may indicate degeneration or pathology of portions of the nervous system, often performed reflex test can help pinpoint the area (level) of the spinal cord injury
what result of reflex (3)
distorted
exaggerated
absent
motor nerves above or below these may be unable to participate in normal flex activity
lesions
used to elicit a response from the deep tendon reflexes
reflex hammer
tested by placing the tip of the index finger on a relaxed jaw, one that is about one-third open, and tapping brisky on your index finger noting the speed of the mandible
jaw jerk
CN nerve involved in jaw jerk
CN5: Trigeminal Nerve
somatic reflex
monosynaptic reflex
involve CN5
masseter and temporalis
location: lower jaw bone
jaw jerk
tested by supporting the forearm, either resting on the patient’s thighs or resting on the forearm of the examiner, placing the thumb firmly over the biceps tendon and curling your fingers around the elbow. Tap briskly, the forearm should flex with the elbow
biceps reflex
what nerevs are involved in biceps reflex
Cervical 5 and 6
Somatic reflex
Monosynaptic reflex
Involve C5 and C6
Biceps
Location: biceps tendon
biceps reflex
tested by finding the brachioradialis tendon at the base of the styloid process of the radius and placing the thumb of hand supporting the patient’s elbow on the biceps tendon. Three potential reflexes can show: brachioradialis reflex, biceps reflex, finger jerk
brachiodradialis reflex
flexion and supination of the forearm
what reflex
brachioradialis reflex
flexion of the forearm
biceps reflex
flexion of the fingers
finger reflex
what nerves are involved in brachioradialis reflex
C5 and C6
Somatic
Monosynaptic reflex
Involve C5 and C6
Radial nerve supply
brachioradialis reflex
tested by positioning the subject’s hand in the supinated position with fingers slightly flexed, and placing the examiner’s index and middle fingers across the tips of the patient’s fingers and tap with the reflex hammer
finger jerk
Reflex contraction of the patient’s finger flexor muscles is a positive response
finger jerk
what nerves is innervated in finger jerk
C6-C8
Monosynaptic reflex, somatic, innervates C6, C7, and C8
Involves median and ulnar nerves
finger jerk
in finger jerk, this may be from cervical compressive myelopathy
hyporeflexia
– in finger jerk, this may be from corticospinal tract lesion
hyperreflexia
tested by supporting the patient’s forearm by cradling it with yours or placing it on the thigh, tapping the triceps tendon and a positive test shows the extension of the forearm
triceps reflex
what nerves are innervated in triceps reflex
C7 and C8
Somatic, monosynaptic reflex, involves C7 and C8 nerves
Involves the triceps and the triceps tendon
Triceps reflex
done by tapping the tendon directly below the patella showing an extension of lower leg
patellar reflex
what nerve is involved in patellar reflex
L2, L3, L4
Somatic and monosynaptic reflex involving the L2, L3, L4 nerve moving the quadriceps femoris
patellar reflex
decreased or absent patellar tendon reflex
westphal’s sign
cns disorders including amyotrophic lateral sclerosis, multiple sclerosis. Upper motor neuron lesions
hyper reflexive response
tapping the achilles tendon just above its insertion on the calcaneus
achilles reflex
what nerve is involved in achilles reflex
L5, S1, S2
Somatic, monosynaptic reflex involving L5, S1-S2, gastrocnemius and soleus
achilles reflex
the reflex hammer is used to draw a light stroke up the lateral side of the sole of the foot and across the ball of the foot
plantar reflex
plantar reflex is also known as
Babinski reflex
Normal response is plantar flexion of the toes
plantar reflex
what nerve is involved in plantar reflex
L4, L5, S1, S2
Somatic, polysynaptic reflex that involve L4-S2 nerves
Involve extensor hallucis longus, tibialis anterior soleus, and plantaris
plantar reflex
indicates potential damage to the reflex arc itself, including the sensory nerve fibers, spinal cord, or motor nerve fibers.
hyporeflexia/areflexia
Possible implications include neuropathy (damaged nerves), nerve root compression, spinal cord lesions, Guillain-Barre syndrome, vitamin deficiencies, metabolic disorders, toxins, genetic conditions
hyporeflexia/areflexia
Suggests a problem with the upper motor neuron pathway, specifically the descending inhibitory signals from the brain
hyperreflexia
Possible Implications: Stroke, brain tumor, multiple sclerosis, amyotrophic lateral sclerosis (ALS), meningitis, encephalitis, brain trauma, metabolic disorders, certain medications.
hyperreflexia
