what is the general process of CNS receiving signals? correct answers receptors receive signals --
> send info to CNS --> CNS responds to stimuli
what are the general functions of the nervous system? correct answers responsible for storing
experiences (memory) and establishing patterns based on previous experiences (learning)
parts of CNS correct answers brain and spinal cord
Peripheral Nervous System (PNS) correct answers neurons outside CNS, two parts: sensory and
motor
regions of a neuron correct answers cell body, dendrite, axon
cell body contains the ______ correct answers nucleus
what does a dendrite do? correct answers receptive area that can conduct electrical impulses
towards cell body
what is the axon? correct answers aka nerve fiber, carries electrical message (action potential)
away from cell body
what are schwann cells filled with? correct answers they are filled with myelin
what does myelin do? correct answers increases axon diameter = more myelin = increases neural
transmission speed
what are gaps between myelin called? correct answers nodes of Ranvier
irritability correct answers ability of dendrites and neuron cell body to respond to a stimulus and
convert it to a neural impulse
conductivity correct answers transmission of impulse along axon
nerve impulse correct answers electrical signal carried length of axon
depolarizatoin correct answers cells becomes positive
repolarization correct answers cell becomes more negative
what types of ions can you move? correct answers you can only move positively charged ions-
negative ions stay in the cell
, what is the state of a cell at resting membrane potential correct answers unequal distribution of
charged ions across cell membrane, neurons are negatively charged inside cell (compared to
charge outside of cell)
how many mV is resting membrane potential correct answers -40 to -70 mV
what is the magnitude of RMP determined by? correct answers 1. permeability of cell membrane
to different ions
2. Difference in ion concentration between intra- and extra cellular fluid
what is in greatest ion concentration? correct answers sodium, potassium, and chloride
what ion is in greatest concentration inside the cell? correct answers potassium
what ion is in greatest concentration outside the cell? correct answers sodium and chloride
how is cell permeability regulated? correct answers channel proteins within the membrane can be
opened and closed by "gates" within a channel
which direction do ions move? correct answers they go from high to low concentration
what is the state of Na and K at rest correct answers Na channels are closed and the K are open,
the K leaving is greater than the Na entering resulting in negative resting potential
what are negative membrane potential primarily due to diffusion of K+ out of cell caused by?
correct answers 1. higher permeability for K+
2. concentration gradient for K+ (promotes movement out)
a small amount of ions are always moving across the membrane. What prevents continued K+
leaving cell and Na+ entering, thus resulting in loss of negative membrane potential? correct
answers sodium potassium pumps, they use ATP to maintain intra/extracellular ion concentration
by continually pumping Na+ out and K+ in
what is the ratio of Na+ to K+ leaving the cell? correct answers exchanges 3 Na+ for every 2K+
how does depolarization work in action potentials? correct answers Stimulus reaches neuron
membrane --> opens sodium gates --> sodium ions diffuse into neuron, thus making cell more
and more positively (+) charged
How is action potential reached? correct answers Depolarization reaches critical "threshold" -->
more sodium
gates open --> action potential (i.e., nerve impulse)
rowdies repolarization work in action potentials? correct answers neuron returns to resting
membrane potential (negative charge) so the nerve can be stimulated again