Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key


Play button


Play button




Click to flip

53 Cards in this Set

  • Front
  • Back
conduction of action potential from presynaptic neuron to post synaptic neuron
presynaptic --> releases neurotransmitters --> synaptic cleft --> cross to neurotransmitter receptors on postsynaptic neuron --> passes signal along axon of post-synaptic neuron --> it becomes more permeable to Na+ --> Na+ enters, causes graded potential --> action potential transfers down post-synaptic axon.
combination of many small depolarizations adding to one another in space and time. If enough depolarizations in a summation occur to reach the threshold potential, an action potential is generated.
how membrane potential comes about and how it's maintained in a neuron
large depolarization occurs as a result of stimulus, action potential is generated, opens voltage regulated channels at hillock, causes more voltage reg. channels to open,( all down axon until termination. Voltage gated Na+ terminals then close, lastly slower K+ channels close. Closing of these causes net movement of pos. ions out of cell (na+ stops diffusing in, K+ diff. out.) returning axon to norm. Na+-K+ pump has same purpose in neuron.
absolute refractory period
period after an action potential during which another action potential can not be generated as the channels are still open.
post synaptic neuron
the neuron that is activvated by the neurotransmiitter at a synapse.
gap junction
Special proteins in muscle cells that extend from cell membranes to function as "tubes" joining to gap junctions in adjacent cells, and allowing the transmission of electrically charged ions between cells. Gap junctions allow these electrical signals to pass between cells at distances that electrical signals couldn't normally jump. This allows for the action potential in one muscle cell to the next, allowing for contraction of the muscle
why is energy required to pump Na+ out of cell
cell membrane not as permeable to Na+, won't diffuse out on its own, plus, going against electrical gradient, so requires energy.
released by neuroendocrine cells, chemical messengers which nerve cells release into the bloodstream to effect another area of the body such as oxytocin which influences milk output of the mammary gland in response to suckling.
Explain the synaptic delay
half a millisecond - time it takes for the neurotransmitter to be released, cross the synaptic cleft, activate the post-synaptic neuron to become more permeable, and for Na+ to enter and cause the graded potential.
concentration gradient
difference in concentration of ions in solution on either side of a selectively permeable membrane
convergence versus divergence - significance?
convergence - many neuron inputs join to one. divergence - one to many. Significance - input from many senses goes towards one 'reaction.' sight of steak, hear sizzle, smell it, all contribute to a neuron to induce hunger. Or, input from vision, muscular control, memory, emotions, all go to control an action - jump shot.
synaptic transmission
transfer of information from neuron to another cell by chemical means.
chemical messengers that are secreted by glands- travel throughout the entire body, have one or more targets and many different effects, but receptor cells in target areas elicit different responses.
axon hillock
where the cell body of the neuron narrows to become the axon, the first region where voltage-gated ion channels occur, and where action potentials are generated.
joining of the output of many pre-synaptic neuron into one post synaptic neuron.
net diffusion
the total movement of ions across a selectively permeable membrane until a balance is reached in both electrical charge and ion concentrations on both sides of the membrane.
one nerve cell providing output to numerous post-synaptic cells.
axon collateral
side branch of an axon.
how is active transport important in ensuring that action potentials can be generated. Discuss why important
creates potential as a side benefit, but changing ion concentrations, thus creating the potential across the membrane. The electrical charge is the basis for action potentials to be possible. Other importance of active transport - ion regulation ensures cell volume homeostasis.
relative refractory period
period following an action potential when the membrane is nearly back to resting potential, and during which another action potential can be generated, IF, the stimuli is stronger than usual.
How can a post synaptic neuron become hyperpolarized?
certain neurotransmitters produce depolarizing graded potentials that reduce the chance that an action potential will be generated.
a specialized junction that allows communication between a neuron cell and another cell type.
Sim & diff between graded and action potentials
both cause changes in membrane potential, but action a large, rapid change, sweeps down axon and can't be stopped once started. graded have different levels, can be small changes. Produced by chemically gated channels opening due to binding of a receptor.
all-or-none rule of action potentials
action potentials are alike in amplitude and shape, so you either generate one, or not.
autocrine factor
localized chemical messengers which release their chemical message into the extra-cellular space, but effect their own cell. (An autocrine factor may be, as an example, a factor which stops a cell from entering the cell division phase of life.)
active transport
The active movement of molecules through the cell membrane by proteins. Primary active transport transports molecules by using the energy generated from the breakdown of Adenosine tri-phosphate into Adenosine di-phosphate (and water) while secondary active transport uses the wasted energy created in the process of moving one molecule across the cell membrane, to move a second (bonus) molecule across the membrane as well.
chemicals secreted by glands to travel via the bloodstream to another body site to exert its effect
neuroendocrine cells
neurons with axon terminals not by another neuron but which instead release neurohormones into the bloodstream.
paracrine factor
localized chemical messengers synthesizing and releaseing their chemical messages from cells to deliver their message via the extracellular space to their nearby target cells.
How an action potential moves along the axon of a nerve cell
review and add answer.
(Axon drawing)
cell body
axon hillock
axon collateral
axon terminal
the return of the membrane potential to normal resting potential
a group of paracrine factors found in nearly every organ and tissue and made up of fatty acids.
Differences between chemical and electrical gradient
ion concentration versus charge across a membrane.
when the inside of the cell becomes less polarized by additional Na+ positive ions entering it, reducing the membrane potential.
When the membrane potential is much more negative than normal, the membrane is hyperpolarized. This is caused by the outward diffusion of positively charged ions, leaving a surplus of negative ions.
electrochemical gradient
combination of concentrations and voltages at which chemical forces move ions.
axon terminals
at the end of the axon, specialied region for transmitting information to another cell.
graded potential
a change in the polarity and permeability of the cell membrane when chemically gated channels open due to binding of a particular receptor.
threshold potential
the membrane potential at which an action potential is generated.
selective permeability
the ability of some membranes to allow certain substances to pass through them, but not other substances.
voltage gated Na+ channels
channels within the axon hillock and axon which, when activated by an electrical impulse, allows the passage of positively charged sodium through the channel.
membrane potential
the difference in charge between cell exterior versus interior. Most membranes are about 70 mV. Generally more positively charged ions outside of cell - this causes the potential, which is then available to perform work. Active pumping of sodium and potassium through protein pumps enhances the potential.
electrical gradient
a difference in electrical charge across a selectively permeable membrane that causes net movement of positive ions toward the negatively charged side of the membrane.
action potential
a large and rapid change in membrane potential that sweeps down the axon and cannot be stopped once started.
nodes of ranvier
points where myelinated sheath are interrupted, in effect, a new action potential is created at each one.
myelinated axon
a nerve cell that is coated at regular intervals with a myelin insulative coating.
resting membrane potential
the normal potential of the membrane when not receiving sensory input. About 70mV. Potential is generated by the difference in charge between the interior and exterior of the cell.
presynaptic neuron
neuron that releases a neurotransmitter at a synapse in response to an action potential in its axon
synaptic bulb
at the axon terminal of a presynaptic neuron, the bulb contains chemical neurotrnamitters that are packaged in vessicles and released after an action potential into the synaptic cleft (the space between a pre and post synaptic nerve cell.)
a chemical released from a pre-synaptic neural axon that delivers a chemical message across the synaptic cleft to the neurotransmitter receptors on the post synaptic neuron.
function of the Na+ - K+ pump
controls the total number of solutes in the cell to maintain homeostatic cell volume. The action potential produced is an indirect benefit, as is the secondary active transport of other molecules that the cell needs - i.e. use of facilitated diffusion to brind in other required molecules.
saltatory conduction
impulse conduction from node to node (ranviers nodes). This is a much faster form of impulse conduction because it doesn't require the opening and closing of ion channels. Allows for increased conduction speed without increasing the diameter of the axon.