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Exam 1 Concepts
Fundamentals of Neurobiology
Question | Answer |
---|---|
neurons are amitotic so how is learning and memory achieved? | new connections between neurons are formed, new cells are not formed |
neurons generate one of two states only due to | all or nothing principles |
do the characteristics of the states of neurons change? | no |
integration | neurons integrate signals from many other neurons into one signal |
what are the particles responsible for electrical current | K+, Na+, Ca+, Mg+2 |
what is the difference between Na+ and K+ pumps in resting membrane potential | Na+ pumps are tightly clamped so there is no movement of Na+ and K+ pumps are leaky so there is very slow and minimal minimal movement of K+ |
what type of transmembrane protein is Na+ pump | selective gated ion channel |
what type of transmembrane protein is K+ pump | ion channel |
describe the electrochemical gradients of Na+ and K+ | Na+ : electrical influx and concentration influx K+: electrical influx and concentration eflux |
why is the resting membrane potential -70 mV | is the necessary size of the electrical field to offset the concentration gradient of K+ so there is basically no net movement of K+ |
what are the proteins responsible for the -70 mV resting potential | Na+/K+ ATPase antiport that pumps 2 K+ into cell and 3 Na+ out while there is a leaky K+ ion channel |
what is the purpose of the undershoot and does it happen all the time | it causes refraction and changes neurons ability to have another action potential since the neuron is hyperpolarized and therefore would require more stimulus to start an action potential, hence preventing the neuron from overstimulating |
what is the purpose of refraction | prevents backpropagation so action potential is unidirectional and prevents neuron from overstimulating |
what is the difference between absolute refraction and relative refraction | absolute makes sure action potential is unidirectional. relative refraction prevents overstimulation and rundown of concentration gradients and occurs during undershoot, it controls the number of action potentials allowed in a given time period |
why is the axon and axon hillock the only place where an action potential can be generated | is has sufficient density of Na+/K+ channels |
why do action potentials need to be regenerated along the axon | loss of current occurs due to loss of charging capacitance to membrane of axon and to external environment |
how are size and speed of action potentials related | larger axons lose less charges to capacitance and have faster propagation speeds |
where are neurochemicals produced and how are found in the terminals of neurons | neurochemicals are produced in the cell body, packaged in vesicles, and moved to terminal via kinesins |
where are neurotransmitters synthesized | in terminal from the neurochemicals in vesicles |
what defines the function of a neurotransmitter | its receptor |
describe electrical synpases | they have high fidelity but low flexibility and are most likely used in developmental neurological systems |
why are inactivation f neurotransmitters important | it allows information to be passed and not aggregated back/forth between neurons therefore allowing unidirectional travel of a signal |
what are the methods of neurotransmitter (NT) inactivation | enzymatic degradation, reuptake, biotransformation, diffusion |
how is the spinal cord developed | ectoderm becomes neuroectoderm which becomes the dorsal hollow nerve cord (fluid filled) via invagination of the mesoderm |
how was the brain gotten bigger and more complex without creating huge heads | folding in on itself |
how do we get more cortex without bigger brain | infolding of cortex |
what are the protecting mechanisms of the brain | # of neurons- requires a great amount of loss for function loss. skull- compact and spongey material that diverts mechanical force throughout mass of whole bone. hydrostatic pressure of of CSF and and tight junctions that make the blood brain barrier |
what allows for the flexibility of your spinal cord | the meningese or dura does not attach to the vertebral column but only at the sacral canal |
where would you extract CSF | in the lumbar region of the spinal cord |
where would insert anisthetic into epidural | in the thoracical region of the spinal cord |
each segment of spinal cord is specific for a specific dermatome but | each spinal nerve comes from and goes to one segment above and below as well |