BB wk 1- Peripheral Nervous System Flashcards
the perineurium is continuous with what structure?
the arachnoid membrane
what are normal values for glucose and RBC’s its the CSF?
glucose = 4.onM, RBCs = 0
what are abnormal values for protein and WBC?
protein = 3.5 G/L WBC = 10/mm cubed
what does the axon of an alpha motor neuron generate?
the CMAP waveform, the compound muscle action potential is a summation of the APs from several muscle fibers. if nerves suppling the muscle become demyelinated, can have problems with conduction, or CMAP amplitude
what are the clinical signs of LMN lesion?
fibrillations, muscle weakness, muscle wasting, decreased reflexes ( hyporeflexia),, no clonus, babinski or bing signs
pacinian corpuscles do what?
perceive deep pressure, and are an example of mechano receptors because they need mechanical deformation of the receptor to open ion channels and depolarize
what nerve does sensory ( mostly) to the head?
CN V
efferent activity to the intrafusal muscle fibers is carried in:
axons of the gamma-motor neurons
what is generator potential and what is the typical generator potential of a mechanoreceptor?
generator potential is the change in potential needed to activate the receptor. it can be a stretch that depolarizes the receptor, as in mechanoreceptors, or it can be light that hyperpolarizes you like in photoreceptors.
what do meissners corpuscles react to?
light touch
what does a normal CMAP, with decreased conduction velocity mean on EMG study?
the neuropathy is promarily affecting the myelin sheath, as its just conduction speed thats off
which axons are myelinated by schwann cells?
“axons transmitting the dynamic signal fro muscle spindles”. primary myelination cell of the PNS. recall this week was guillan barre
the sensory innervation of muscle spindle is primarily detect what?
changes in muscle length
name 4 features of guillian barre syndrome
Increased CSF potein, proximal weakness, reduced conduction velocities on peripheral nerve conduction studies, diffuse arreflexia, with peak deficits within 3 weeks of onset
while attending a hockey game, person is hit in the temple with a stray puck. The middle meningeal artery is lacerated. blood from the laceration will go where?
epidural space. they will wake up the next morning with a headache, and they will go unconcious relatively late after the headache because the blood takes alot of time to rip the dura off the skull, its very tightly adherent
infections of the scalp can spread to the meninges via
the emissary veins
the fourth ventricle is located where?
between the pons and cerebellum
what are structures of the brainstem?
the midbrain, pons and medulla make up the brainstem, NOT the basal ganglia
what are the components of the central nervous system?
the cerebellum, medulla and midbrain are parts of the CNS, but NOT the cranial nerves. The cranial nerves are analagous ot the spinal nerves and are part o fthe peripheral nervous sysmte
in what space does the CSF flow?
the subarachnoid space
what do the cerebral peduncles contain, information-wise?
descending motor informatino. these are prominent on the ventral surface of the midbrain.
a typical example of a pseudo-unipolar neuron is
a neuron in the dorsal root ganglion. this is opposed to options such as the alpha or gamma motor neurons
how do you get from the lateral ventricles to the third ventricle?
either called the foramen of monroe, or the interventricular foramen
white matter appears white because of the presence of what substance?
myelin
what type of fibers is the corpus callosum
comissural fibers
if you were to poke someone from the outside of their skull into their brain, what layers would you hit?
hair, skin, scalp, skull, dura, subdural space, arachnoid, subarachnoid space, pia, cortex
what induces the neural plate to form?
the notochord
cells in the basal plates of the developing spinal cord give rise to what kind of neuron>
motor neurons.
the cell bodies of spinal motor nerves develop in the:
basal plate
what does the telencephalon give rise to, in the adult
the cerebral hemisphers
sympathetic postganglionic neurons are derived from:
neural crest
