nervous system Flashcards
(45 cards)
CNS (central nervous system)
includes the brain and the spinal cord
PNS (peripheral nervous system)
nerves that branch off of the CNS
neurons
- have electrical potentials
- characterised by “irritability” and “conductivity”
- electrically unstable cell membrane
glial cells
support neurons in a variety ways (structure, nutrients and regulation)
neuron functions
- input sensory neurons (afferent)
- output motor neurons (efferent)
- interneurons (located inbetwen sensory and motor neurons)
multi-polar neurons
have multiple connections to the cell body
bipolar neurons
have two connections to the cell body
pseudounipolar neurons
has one axon that splits into two branches
pseudounipolar neuron branches
peripheral and central branch
cell body
soma
schwann cells
wrap around axons and from a myelin sheath
myelin sheath
fatty protein-based membrane that surrounds neurons
nodes of ranvier
a 1mm gap in a schwann cell that helps electrical impulse conduction and the re-growth for neurons after they are damaged
electrical potential
voltage across the cell membrane (Vm)
resting potential
voltage across the cell membrane in an inactive neuron (Vrest)
intracellular fluid (icf)
has high concentration of potassium (K+) ions
extracellular fluid (ef)
has a high concentration of sodium (Na+) ions
what happens to the voltage when the sodium concentration gradient pushes sodium into the cell?
it decreases
what happens to the voltage when the electrical gradient pushes sodium out of the cell?
it increases
what happens when the sodium concentration gradient and electrical gradients balance?
the sodium does not move, leading to an equilibrium potential
what chemical ions get pumped into the cell by ATP?
potassium (K)
what chemical ions get pumped out of the cell by ATP?
sodium (Na)
what is the cell membrane not permeable for?
ions
how do ions cross the cell membrane?
- active transport with help from proteins and energy in the form of ATP
- across ion channels (ion specific)
