The Nervous system Flashcards
This part of the neuron receives info form other cells
Dendrites
This part of the neuron holds all the normal cell components (nucleus, ribosomes, endoplasmic reticulum, etc.) and also is the main body of the cell
Soma
This cell type isolates against signal loss on the axon, and is referred to as Schwann cells in the PNS and oligodendrocytes in the CNS
Myelin
This part of the neuron integrates signals and starts signal transmission down the axon by summing up all the signals and seeing if they’re enough to cause an excitatory state
Axon hillock
This part of the axon is formed from the breaks in myelin that allows for rapid signal transduction
Nodes of Ranvier
This part of the neuron is located at the very end of the axon and releases neurotransmitters to their target
Nerve teminal
The _____ includes the synaptic cleft, the axon terminal, and the post-synaptic membrane
Synapse
What is the difference between nerves and tracts?
Nerves are many bundles of neurons in the PNS, and can be sensory, motor, or both
Tracts are made up of axon bundles in the CNS that cluster into nuclei and can only be made up of one type of cell per cluster (motor or sensory)
These glial cells form the blood/brain barrier
Astrocytes
These glial cells line the ventricles and produce cerebrospinal fluid
Ependymal cells
These glial cells are phagocytic cells that ingest and break down waste
Micoglia
_____ cells act as support for the neurons
Glial
At rest, the neuron is more negative _____ than _____
Inside than outside
Potassium is at a higher concentration ____ the cell than _____
Inside than outside
Sodium is at a higher concentration _____ the cell than _____
Outside than inside
Potassium leak channels allow potassium to flow _____ the cell while sodium leak channels allow sodium to flow ____ the cell
Out of
Into
When the axon hillock receives an overall inhibitory signal, the cell ___ polarizes and is less likely to incur an action potential
Hyperpolarizes
inHibitory –> Hyperpolarizes
When the axon hillock receives an overall excitatory signal, the cell ___ polarizes and is more likely to incur an action potential
Depolarizes
Excitatory –> dEpolarizes
What is the difference between temporal and spatial summation?
Temporal summation occurs when multiple signals are integrated over a short period of time (based on time)
Spatial summation occurs when the additive affects are based on number and location of signals (based on position in space/location)
Explain the entirety of action potential, from the beginning of stimulus to the return to resting potential
When the summation threshold is reached, sodium rushes into the cell until the cell reaches -50 mV. At +35 mV, at which point the action potential is reached, K+ channels open and allow K+ to leave the cell. This attempts to restore the resting potential, but overshoots it and causes hyperpoalization. This then results in a refractory period in which the cell cannot achieve another action potential as it returns to its resting potential
What is the difference between absolute and relative refractory periods?
In absolute refractory periods, there is no amount of stimulation that can cause another AP to occur
In relative refractory periods, only greater than normal stimulation can cause an AP
How do myelin and the nodes of Ranvier work together to allow for fast transmission of the AP?
The myelin insulates the axon, but the nodes of Ranvier are perfect for transmission. Bc of this, the AP jumps from node to node and this speeds it up
This specific channel moves 2 K+ into the cell for every 3 Na+ ions and is responsible for restoring the resting potential of the cell
Na+/K+ ATPase
