CNS support structures Flashcards
Lateral ventricles - communicate with third via
foramen of monro
Third ventricle - located
posterior and deep between the two thalami
Third ventricle communicates with fourth through
cerebral aqueduct
Fourth ventricle - located
in pons and medualla
Fourth ventricle - communication
Foramina of Luschka and Magendie communicate with fourth ventricle via subarachnoid space
CSF produced where
in choroid plexus in ventricles
Blood supply - brain is ___% of body weight with a circulation of ___% of total blood volume
2% of body weight
18% of total blood volume
Blood supply - carotid system
internal carotid arteries arise off common carotids and branch to form anterior and middle cerebral arteries
Blood supply - vertebrobasilar system
vertebral arteries arise off subclavian arteries and unite to form the basilar artery
Basilar bifurcates into posterior cerebral arteries
Supplies brainstem, cbm, occipital lobe, parts of thalamus
Blood supply - circle of willis is formed by
anterior communicating artery, connecting two anterior cerebral arteries
posterior communicating artery, connecting each posterior and middle cerebral artery
Neurons - axons conduct impulses in what direction
away from the cell body (one way conduction)
Neurons - resting membrane potential
positive on outside, neg on inside
about -70 mV
Neurons - action potential
increased permeability of Na and influx into cell with outflow of K resulting in polarity changes - depolarization and generation of AP
Neurons - conduction velocity is proportional to
axon diameter
Nerve fiber types - A fibers are
large, myelinated, fast conducting Alpha - proprioception, somatic motor Beta - touch, pressure Gamma - motor to muscle spindles Delta - pain, temp, touch
