Neurons + Glia Flashcards
neurons
like other cells but with very specific properties
glia
non-neural cells playing a supportive function
different types of glia
Astrocytes, Microglia, Oligodendrocytes
how do neurons work
- collects input
- processes the information and decides in some way what to do with it
- produces output or doesn’t
presynaptic
the neuron that is sending the information to another neuron
postsynaptic
-the neuron that is receiving the information from a neuron
- postsynaptic will become presynaptic once is passes on the information it has just received
afferent
accepting/input/coming in
efferent
exiting/output/going out
soma (afferent)
the cell body containing the metabolic machinery that maintains the neuron
axon (efferent)
communicates output of the neuron –> starts in the axon hillock travels through the neuron, and ends at the presynaptic terminal button where it releases neurotransmitters
dendrites (afferent)
receives input/information from neurons at synapses (postsynaptic); treelike look, spiny endings
membrane
encloses the cytoplasm in the neuron; it is responsible for keeping certain ions outside of the cell and letting others in
bilayer
this forms the framework of the membrane, permeable to potassium
myelin
helps to speed along the electrical circuit; insulates the axon
astrocytes
the blood-brain barrier (separates the
circulating blood from the brain extracellular fluid in the CNS), maintenance of extracellular ion
balance, and repair scarring process of the brain and spinal cord following traumatic injuries
- Potential differences across membrane
extracellular
outside the cell, has more ion (Na+, Cl-)
intracellular
inside the cell, contains proteins and amino acids, has a concentration gradient (K+)
active
action potential (regenerated at the nodes of ranvier)
action potential
- Cell starts at resting potential (-70 mV)
- Then cell depolarizes with and influx of NA+ until it
reaches threshold - Then repolarization occurs with pump out of K+ (instead
of just leaking out) - Then hyperpolarization occurs because it overshoots the
resting potential (takes more firing to excite the cell;
needs more NA+)
-Then back to resting potential
depolarization
cell becoming more positive (Na+ entering the cell)
threshold of excitation
when NA+ starts to enter the cell theres a certain point where it reaches a certain threshold
