neuro Flashcards
Neurons
functioning cells of the nervous system
Neuroglial cells
protect the nervous system and supply metabolic support
Afferent (sensory) neurons
transmit information to the CNS
Efferent (motor) neurons
carry information away from the CNS
Interneurons
efferent and afferent neurons communicate
Neuron componenet
dendrites, axon, and cell body (soma)
Neuroglial cells of the CNS
oligodendrocytes, astrocytes, microglia, and ependymal cells
oligodendrocytes
form myelin in the CNS
Schwann cells
form myelin in the PNS
Astrocytes
Blood-brain barrier
Ependymal cell
line ventricular system. involved in CSF production
Microglia
phagocytic cells
Satellite cells
protect cell body in the PNS
Saltatory conduction (PNS)
conduction jumps from node to node
Nodes of Ranvier (PNS)
schwann cells are separated by these gaps. voltage0gated sodium channels are concentrated here
depolarization
inward flow of positive ions. Inflow of Na+ produces local positive current, causing Na+ channels to open. (+30mV)
Action potential phases
resting state, depolarization, and repolarization
resting state
(-70mV) is when the nerve is not transmitting impulses. membrane is polarized due to large separation of charge (K+ inside the cell and Na+ outside the cell)
Repolarization
when the polarity of the resting membrane potential is reestablished. Accomplished via Na+ channel closure and K+ channel opening
absolute refractory period
membranes remain refractory and cannot create a stimulus
relative refractory period
membrane can be excited by a stronger than normal stimulus.
Muscular dystrophy
genetic disorders that produces progressive deterioration of skeletal muscles because of mized muscle cell hypertrophy, atrophy, and necrosis.
Muscular dystrophy
DMD is the most common. it is a recessive single-gene defect on the X chromosome transmitted from mother to male offspring.
DMD etiology
mutation of dystrophin
Muscular dystrophy manifestations
muscle weakness with frequent falling at 2-3 years of age. Postural muscles of the hip and shoulders are usually the first to be affected. death from respiratory and cardiac muscle involvement occurs in young adulthood
Muscular dystrophy diagnosis
serum levels of creatine kinase
Multiple sclerosis
inflammation and destruction of myelin in the CNS (oligodendrocytes). onset is 20-30 years and frequently affects females of North European ancestry.
multiple sclerosis pathogenesis
immune response to CNS protein. consists of hard, sharp-edged, demyelinated patches in white matter. lesions=plaque (result of myelin breakdown)
multiple sclerosis manifestations
paresthesias, vision problems, weakness or fatigue, speech disturbance, abnormal gait.
psychological- mood swings, depression, euphoria, inattentiveness, apathy, forgetfulness, and loss of memory.
multiple sclerosis categories
relapsing-remitting: episodes of acute worsening with recovery and stable course between relapses
Secondary progressive disease: gradual neurologic deterioration with or without acute relapses
primary progressive disease: continuous neurologic deterioration from onset of symptoms.
progressive relapsing: gradual neurologic deterioration from onset of symptoms but with subsequent relapses.
Multiple sclerosis treatment
corticosteroids
SCI
most common SCI is motor vehicle crash, followed by falls, violence (gunshot wounds), and sports
SCI involves
motor and sensory function
Most SCI injuries
occur due to writhing movements and a compressive force.
Primary neurologic injury (SCI)
occurs at the time of injury and is irreversible.
Primary neurologic injury (SCI) characterized by
small hemorrhages in the gray matter followed by edematous changes in white matter that lead to necrosis and cell death.
Primary neurologic injury (SCI) results from
forces of compression, stretch, and shear associated with fracture or compression of the spinal vertebrae, dislocation of vertebrae, and contusions.
Secondary injuries (SCI)
follows the primary injury and promote the spread of injury
types of SCI
tetraplegia (quadriplegia), paraplegia, complete cord injuries, and incomplete cord injuries
tetraplegia (quadriplegia)
impairment of function in arms, trunk, legs, and pelvic organs.
paraplegia
impairment of thoracic, lumbar, or sacral segments. arm functioning is spared, but function of the trunk, pelvic, and legs are impaired.
complete cord injuries
severance of the cord. no motor or sensory function is preserved in segments S4 to S6.
incomplete cord injuries
imply residual motor or sensory function below the level of injury. prognosis is better for return of injury.
compression injury (SCI)
causes vertebral bones to shatter, squash, or even burst when there is loading from a blow to the top of the heard. diving injury
axial rotation (SCI)
occurs in the cervical region especially between C1 and C2 and at the lumbosacral joint.
CN I (olfactory) located in forebrain
olfaction (smell)
CN II (optic nerve) located in forebrain
carries visual impulses from eye to brain
CN III (oculomotor) located in midbrain
contracts eye muscles to control eye movements (inferior lateral, medial, and superior), constricts pupils, and elevates eyelids.
CN IV (trochlear) located in pons
contracts one eye muscle to control inferomedial eye movement