Exam 1 Flashcards
what is a neuron?
a cell that detects and responds to stimuli to send information over a long distance
what is a neuroglia?
it is a cell that protects, repairs, and assists neurons
what was the original 1839 cell theory?
that all organisms are composed of one or more cell, the cells are the basic units of structure, and all cells arise from pre-existing cells
(disproven) what was the reticular theory?
that all nerve cells were connected and formed a continuous network
what is a unipolar cell
one who’s dendrites and axons come out of one side of the cell body, the dendrites eventually separating from the axon
what is a bipolar cell
a cell who has two ends, one side has an axon, one side has a dendrite
what is a pseudo-unipolar cell
where the cell body comes off the side of the axon, where the axon goes in both directions, and on one end the axon becomes a dendrite
what is a multipolar cell?
where an axon comes out of one side, and dendrites come out from all kinds of directions
afferent vs. efferent
afferent: info towards the brain (sensory neurons)
efferent: info away from the brain (motor neurons)
neural circuits
(convergent excitation, divergent excitation, feedforward excitation, feedback excitation, recurrent (lateral) excitation, lateral inhibition, disinhibition)
write out and check against image in review
how does a knee jerk reaction work?
- a mallet hits the knee
- the extensor muscle sends a signal to the brain via the sensory afferent neuron
- the sensory neuron sends excitatory messages to an inhibitory interneuron which inhibits the efferent flexor motor neuron, but it sends excitatory messages to the efferent extensor muscle neuron
- this causes the leg to swing forwardw
what is an oligodendrocyte?
it facilitates greater conduction across axons, especially between the nodes of ranviar by myelinating axons
what is a schwann cell?
it is the oligodendrocyte of the peripheral nervous system, and does the same thing but not in the central nervous system
what is a microglia?
an immune cell that removes damage and debris (macrophage)
what is an astrocyte?
they regulate the BBB and create strong K+ buffering, promoting synapse formation
what are glial stem cells?
cells that give rise to new glial neurons
what are types of electrical signals that can give rise to an action potential?
external stimulation (light, sound, pressure, etc.) – usually for sensory neurons
chemical stimulation (via neurotransmitters)
strong stimulation
what is voltage?
the difference in electrical charge between two places
(usually in reference to across a membrane)
what is current
the rate of flow of charged particles
what is resistance
the opposition to flow of charged particles
what can’t pass through a phospholipid bilayer?
polar molecules without active transport
how is the resting potential established and maintained at a neuron membrane?
ATPase pump, leak cells are equal in and out when at electrochemical equilibrium
what is the Nernst equation?
Eion = (58/z) log([x]out/[x]in)
z = the charge of the ion
[x] = ion concentration
what is the Goldman equation?
Vm = (Pk[K]out + Pna[Na]out + Pcl[Cl]in) / (Pk[K]in + Pna[Na]in + Pcl[Cl]out)
Pk = the permeability of that ion across the membrane