Nerve Lab Flashcards
Location of the spinal chord. Begins and ends where? Ends as _____.
begins at the foramen magnum
ends between L1 and L2 as conus medullaris
What is the fibrous extension that anchors the spinal chord to the coccyx
filum terminale
what is the collection of nerve roots at the inferior end of the vertebra canal? What 2 nerves do they contain?
cauda equina
lumbar & sacral nerves
What are the 2 functins of the spinal chord?
- provides communication to and from the brain
- contains spinal reflex centers
What type of neurons are located in the dorsal, ventral, and lateral grey horn?
dorsal = interneurons ventral = somatic motor neurons lateral = visceral motor neurons
Spinal nerve is formed by the union of these 2.
dorsal & ventral roots
The cell bodies of what type of neurons are located in the dorsal root ganglion?
sensory neurons
Myelinated axons run through here (3).
dorsal, lateral, ventral white columns (funiculi)
Damage of the phrenic nerve causes
respiratory failure
What are the 5 nerves in the brachial plexus?
Damage in the brachial plexus causes
- axillary nerve
- musculocutaneous nerve
- radial nerve
- median nerve
- ulnar nerve
- loss of sensation in the arm
Which nerve is in the lumbar plexus? (2)
Where does it innervate?
damage in the lumbar plexus causes (2)
- femoral nerve & saphenous
- quadriceps
- cant flex hips or extend knee
Which nerve is in the sacral plexus?
What does it innervate? (4)
damage in the sacral plexus causes (3)
- sciatic nerve
- hamstring, adductor Magnus, legs/foot
- no flexion of knee, leg useless, “footdrop”
Stretching of this plexus causes a football injury called stinger.
brachial plexus
Which nerve is involve in the carpal tunnel syndrome
median nerve
Which nerve do we hit in funny bone
ulnar
Define reflex.
rapid, predictable, involuntary motor responses to stimuli
Define reflex arc.
nerve pathways of a reflex
Define muscle spindle.
What does it excite and initiate?
What do the golgi tendon organs inform? What does it excite and initiate?
- inform the nervous system of the length of the muscle
- excited by stretch of the muscle, initiate contraction
- inform the brain the amount of tension in the muscle & tendons
- excite by muscle contraction, initiate relaxation
Define monosynaptic vs polysynaptic reflexes.
- mono = one chemical synapse between one sensory and one motor neuron
- poly = more than one chemical synapse involving interneurons
What are the 5 components of a reflex arc? simple
- receptor - site of stimulus
- sensory neuron - transmits afferent impulses to the CNS
- integration center - mono or polysynaptic region withini the CNS
- motor neuron - conducts efferent impulses to an effector organ
- effector - muscle/gland responds by contracting or secreting
Why is reflex testing an important part of every exam? What does a hyperactive reflex indicate? hypoactive?
- test for proper functioning of the nervous system
- hyperactive = damage to the corticospinal tract and loss of brains inhibitory input
- hypoactive = peripheral nerve damage or ventral horn damage
What is the difference between an inborn/intrinsic and learned/acquired reflex? What is an example?
- inborn = a rapid, involuntary, predictable motor response to a stimulus
ex. Splash boiling water on arm, drop pot
-acquired = result from practice or repetition,
Example: driving skills.
all stretch reflexes are _____ and _____.
monosynaptic and ipsilateral
What are the 3 steps to a stretch reflex? What happens at the same time?
- stretch activates the muscle spindle (propioceptor)
- sensory neurons synapse directly with the motor neuron
- motor neuron causes stretched muscle to contract
-inhibit motor neurons of antagonist
