Neurophysiology Flashcards
Action potential
the release of a neurotransmitter
membrane moves ions via?
passive transport when moving into the cell
active transport at rest
sodium potassium pump
3 sodium out, 2 potassium in
electrical gradient
attraction of opposite charges
chemical gradient
flow of ions down concentration
excitatory post synaptic potential
brings us closer to threshold by bringing in NA+
Inhibitory post synaptic potential
brings us away from threshold by letting in CL ions
graded potentials
can depolarize or hyperpolarize cell,
effects of axon diameter
larger diameter, faster impulse
effects of myelination
makes everything faster
Group A fibers
somatic sensory and somatic motor
large diameter, heavily myelinated
fasts, 300mph
Group B fibers
Autonomic
medium diameter, nonmyelinated
30mph
Group C fibers
Autonomic NS
small diameter, nonmyelinated
slow, 2mph
Absolute refractory period
no stimulus can activate another potential
Relative refractory period
another action potential is possible but must overcome hyperpolarization
Synaptic transmission
Transmission across the synaptic cleft is a chemical event that involves release, diffusion, and binding of neurotransmitters. The action potential of +30 mV arrives at the axon terminal of the presynaptic neuron. Opens voltage-gated calcium channels. Calcium binds to Synaptotagmin protein and fuses synaptic vesicle with axon membrane. Neurotransmitters diffuse and bind to receptors on the postsynaptic neuron. The ion channels open causing that second neuron to either inhibit or have an action potential. Within a few milliseconds the neurotransmitter is terminated either by breaking it down, reuptake by putting it back where it came from, or diffusing it away from the synaptic cleft.
Dopomine
neurotransmitter found in CNS
can plead to addiction
parkinsons disease
synaptotagmin
protein that binds with Ca++ and promotes fusion of synaptic vesicles with axon membrane
Serotonin
associated with mental and emotional disorders
etc. depression, OCD, bipolar, anxiety, migraines
Exteroceptors
stimuli outside the body
Interoceptors
stimuli in internal organs
Proprioceptors
stretch in joint tissue
Thermoreceptors
changes in temperature
mechanoreceptors
respond to touch, pressure,vibration
photorecepters
light energy
chemoreceptors
chemical changes in blood
Nocireceptors
extreme stimuli like getting burned
sensation awareness
awareness of changes in the internal and external environment
perception
conscious interpretation of stimuli
Cognition
mental process of awareness, knowledge, memory, perception and thinking
Serial processing
perceive inputs one at a time
Parallel processing
perceiving inputs simultaneously
etc.. noting the color, direction and speed of a ball being thrown at you
sensory memory
association based on sensory input
short-term memory
limited and brief, seconds to hours
long-term memory
can be from short-term memory if information is repeated, may exist for a long time
Dorsal horns
receive somatic and visceral sensory input
ventral horns
somatic motor neurons
lateral horns
sympathetic neurons
Dorsal root
contain cell bodies of sensory neurons
neuron pathways
first order= impulses from sensory to receptors (spinal cord)
second-order= axon extending to thalamus or cerebellum
third-order= extending to somatosensory (thalamus)
medial lemniscal tract
mediate fine touch
spinothalamic tract
pain and crude touch
spinocerebellar tract
input for balance
upper motor neurons
primary motor cortex
lower motor neurons
innervate skeletal muscle
Pyramidial (corticospinal) Tract
fast and fine skilled movements
indirect (extrapyramidal) system
balance and posture, head, neck, and eye movements
functional loss in anesthesia
sensory loss
Paralysis
loss of motor function
flaccid paralyis
damage to ventral root/horn
no voluntary or involuntary control of muscle
spastic paralysis
damage to upper motor neurons of primary cortex
no voluntary control of muscle
stimulated by reflux activity
autonomic nervous system
controls smooth muscles, cardiac, and glands
preganglionic nerve
nerve bringing signal into ganglion
postganglionic nerve
nerve carrying signal away from ganglion
beta receptors
lowers BP
