unit 3 Flashcards
Ependymal cells
Neural support cells in the CNS. Neural cells that form a barrier between brain cells and the actual fluid cavities in the brain (ventricles) some secrete cerebrospinal fluid
Oligodendrocytes
Neural support cells in the CNS. They create the myelin sheaths. They can myelinate a few axions with its multiple arms.
Microglia (modified immune cells)
Neural support cells in the CNS. They are a so-so defense not great at defending brain from pathogens. They are good at being scavengers during brain development. they refine or prune the brain connections and refine circuitry.
Astrocytes
Neural support cells in the CNS. Physical cells that stand between blood supply and irreplaceable neurons (blood brain barrier). they synthesize substrates for ATP and pass substrates. Body guard and pass good stuff from the blood and prevent bad things from passing. they tend to the environment of the neuron.
Schwann cells (neurolemmocytes)
Neural support cells in the PNS. They create myelin sheaths for the PNS. one cell makes one myelin.
Satellite cells
Neural support cells in the PNS. Protect the neuron that are outside the CNS (outside the physical brain or spinal cord)
interneurons
Communicate within the CNS. They typically have lots of dendrites and look like coral.
Sensory neurons structure/look
They typically have a cell body in the middle with the axon and the dendrites coming out of the other two ends.
These cells are the functional unit of the nervous system
Neurons
These cells are the only part of the immune system that has access to the nervous system.
Microglia CNS
These cells form the myelin sheaths in the Peripheral nervous system
Schwann cells or neurolemmocytes. They are the 1:1 myelin creators in the PNS
These support cells provide neurons with essential bio-molecules for ATP production and form the blood- brain barrier.
Astrocytes of the CNS.
These cells line the walls of the fluid filled chambers of the brain (ventricles)
Ependymal cells of the CNS
These cells can myelinate more than one neuron.
The microglia of the CNS.
What mV do neurons typically rest at. What do they need to reach to generate an action potential?
They rest at -70mV and they need to reach -55mV or at least a +15 mV change.
What influxes at an excitatory synapse in the neuron
Na+ or Ca2+ influx. Creating a more + environment or depolarizing the cell.
What influxes in the inhibitory synapse?
Cl- influx, repolarizing the cell or creating a more - environment.
What is an EPSP
Excitatory post-synaptic potential. They increase the likelihood of an action potential. They depolarize the cell with an influx of Na+ or Ca+.
What is an IPSP
Inhibitory post-synaptic potential. The decrease the likelihood of an action potential. They repolarize or hyperpolarize the cell by Cl- influx or sometimes K+ efflux.
What are graded potentials?
Changes in the membrane potential in the dendrites and cell body upon binding a neurotransmitter. The more signal molecules that are received by either an excitatory or inhibitory synapse then dictates how strong the stimulus is. The faster/higher rate of signal molecules that are received the greater the change in a neuron’s membrane potential.
How the graded potentials happen in a little flow chart.
More signal molecules received –> more binding to receptors –> more channels open –> more ions move –> greater graded potential in target cell
What is the “trigger zone”
The area where the sum of the EPSPs and IPSPs is recognized and it is determined if there is enough voltage change to generate an action potential (at least +15mV). The trigger zone in a neuron is the Axon Hillock.
Sub/Supra graded potential
Sub means no action potential will be generated. Supra means it will.
What is integration (in terms of action potentials)
The sums of excitatory and inhibitory potentials. Integration is through spatial and temporal summation.
Spatial summation
When more than one neuron is stimulating the cell body at the same time. All over the Space of the neuron.
Temporal summation
Relates to the time the neurons are firing on the cell body. If they are close together they may add to create a larger depolarization. If they are farther apart they may act as individual waves.