Neurons Flashcards
Neuron
specialized cells that can receive and transmit chemical OR electrical signals
- supported by GLIA
Glia Cells
produce support functions for neurons
Neuron Electrical Signal
ACTION POTENTIAL
- transmit information from one neuron to the next
- rapid, temporary change in membrane potential (electrical charge)
- caused by SODIUM rushing to a neuron and POTASSIUM rushing out
Neuron Chemical Signal
NEUROTRANSMITTERS
- transmit information from one neuron to the next
- chemical messengers that are released from one neuron as a RESULT OF AN ACTION POTENTIAL
- cause a rapid, temporary change in the membrane potential of the adjacent neuron to initiate an action potential in that neuron
Soma (CELL BODY)
each neuron has a cell body that contains its nucleus + other cellular organelles and components
Dendrites
structures where neurons receive signals from other neurons; tree-like structures that extend away from the cell body to receive neurotransmitters from other neurons
- some do not have any while some have multiple
- have DENDRITE SPINES, which increase SA for possible connections
Axon
structure where a neuron transmits an action potential to reach the next neuron; tube-like structure that propagates the integrated signal to specialized endings called AXON TERMINALS
- neurons typically have 1-2
- some are covered in myelin
Myelin
acts as an insulator to minimize dissipation of the electrical signal as it travels down an axon; myelination greatly increases the speed of conduction
- myelin sheath IS NOT PART OF A NEURON
- produced by glial cells
Nodes of Ranvier
periodic gaps in the myelin sheath that are sites where the signal is “re-charged” as it travels down the axon
Synapses
location where 2 neurons almost come in contact and a signal is transmitted from one neuron to the next
- one side of a synpase is the axon terminal from the PRE-SYNAPTIC NEURON
- one side is a dendrite/dendrite spine from the POST-SYNAPTIC NEURON
- Synaptic Cleft between the two neurons
Synaptic Cleft
small gap between 2 synapsed neurons where neurotransmitters are released from 1 neuron to pass the signal to the next neuron
Pre-Synaptic Neuron
the neuron sending the signal
Post-Synaptic Neuron
the neuron receiving the signal
Axon Hillock
site where an AP initiates within a neuron + controls whether or not a AP will occur
- a neuron does not necessarily initiate an AP every time a synapse receives a signal
- CONFLICTING SIGNALS ARE “INTEGRATED”
- located between the cell body and axon start
- integration determines whether the neuron will initiate an AP
Neurotransmitter in Tranmission
signal between neurons
Action Potential in Transmission
signal within a neuron (from dendrite to the axon terminal) through a change in membrane potential/electrical charge
- can change in response to neurotransmitters released by other neurons and environmental stimuli
Resting Potential
MP (electrical charge) in a neuron that is NOT currently transmitting a singal; maintained by the Na/K pump and K leak channels
Action Potential
brief polarization (reduction in charge magnitude) along the neuron’s axon; all-or-nothing
- no degrees of magnitude
- regulated by Voltage-Gated Na Channels, Voltage-Gated K Channels, and Na/K Pump
Neurotransmitters
chemical messengers that communicate between adjacent neurons; release of these from one neuron will either help depolarize/hyperpolarize (increase charge magnitude) the adjacent neuron
- makes AP more/less likely to occur in the next neuron
Membrane Potential
the difference in total charge between the inside and outside of the cell
- at rest, is NEGATIVELY CHARGED
- resting membrane potential
Resting Membrane Potential
caused by differences in the concentrations of ions inside and outside the cell; established and maintained by 2 main processes:
1. ATP powered ion channel (NA/K Pump)
2. Passive Ion Channel (K Leak Channel)
Na/K Pump (Na/K ATPase)
