Review Of Intro To Neuro Flashcards
What is the role of oligodendrocytes?
Only found in the CNS; one cell of these myelinates the axon segment of many neurons
What is the role of Schwann cells?
Found in the PNS; one cell myelinates axon segment of one neuron
What is the role of Astrocytes?
End feet of the BBB
What is the role of microglia?
Immune function, modulates inflammation and cell survival in the brain
What are the 3 conditions for a neuron to be at rest?
1) solutions inside and outside the cell are electrically neutral
2) the concentrations of intracellular and extracellular molecules must be in osmotic balance
3) there cannot be any net flux of ions
What four ions contribute to resting membrane potential?
Sodium, potassium, chloride, and proteins
Which ions are found in high concentration extracellularly?
Sodium and chloride
What ions are found in high concentration intracellularly?
Potassium and proteins
What forces act upon ions and contribute to the resting membrane potential?
Diffusive force, electrical force, sodium potassium pump, and permeability although not a force
How many sodium and potassium ions are pumped in/out of the NA/K ATPASE per molecule of ATP?
3 sodium out, 2 potassium in
What are the nodes of Ranvier?
Areas of densely populated ion channels that allow for “hopping” of the AP in propagation down the axon
What are the four general categories of neurons and their functions?
1) sensory: take environmental signals and make them neuronal (sound, touch, pain)
2) motor: cause muscle contraction or control secretions
3) interneurons: modulate activity between nearby regions of the CNS
4) projection neurons: communicate between distant regions of the CNS
What lobes of cortex are separated by the Sylvian/lateral fissure?
Frontal and temporal lobes
What lobes are separated by the central sulcus?
Frontal and parietal lobes
What is the corpus callosum made of, and what is its function?
Functions to connect the two brain hemispheres and is made of projection neuron axons
What cells make up the BBB?
Endothelial cells, pericytes, & astroglial cells with tight junctions
What are some examples of gases that can cross the BBB?
NO, CO2, O2
What is the equilibrium potential of an ion?
The membrane potential where the net flow through any open channels is zero
What is the reversal potential of an ionotropic receptor?
Also the membrane potential where the net flow of ions is 0, but the difference is that receptors can be permeable to multiple ions
What are the 5 components of the AP and what are they characterized by?
1) Depolarization to threshold; sodium current
2) upstroke; sodium current and channels quick to open
3) downstroke; potassium current, K channels sluggish to open and quick sodium channels inactivated
4) after hyperpolarization; potassium current and K channels sluggish to close
5) refractory period; inactivation of NA
Briefly describe the steps of vesicle fusion
1) AP enters terminal
2) membrane depolarizes and Calcium channels open
3) calcium moves into the neuron
4) synaptic vesicles fuse to the membrane
5) NTs released into the cleft
What is the difference between a PSC and a PSP?
PSC refers to the currents that move through channels & PSP refers to membrane voltages
What ions do glutamate channels conduct?
Sodium and calcium in and potassium out
What ions do GABA channels conduct?
Chloride in or potassium out
What is spatial summation?
Multiple inputs from multiple locations converge on the soma depending on distance from the soma
What is temporal summation?
A single input fired at a high frequency
What are the differences between APs and PSPs?
APs are all or none, always excitatory, and do not degrade
PSPs degrade, can be excitatory or inhibitory, and are proportional to the intensity of the stimulus
What is the orientation of gray and white matter in the brain and spinal cord?
Gray is on the outside in the brain and on the inside in the spinal cord. White matter is on the inside in the brain and on the outside in the spinal cord.
True or false: there are some regions of the brain that do not contain the BBB
True
What is the role of SNARE proteins?
To mediate the vesicle fusion with the plasma membrane during NT release
When there is no net flux of ions across the membrane, what two forces are balanced?
Diffusive and electrical
What is the equilibrium potential for potassium?
-90 mV
What is the equilibrium potential for sodium?
+60 mV
What is the equilibrium potential for chloride?
-70 mV
What is the equilibrium potential for calcium?
+ 134 mV
What are the cell effects of glutamate and then GABA?
Excitatory and inhibitory, respectively
