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Cell Bio and Electrophysiology of the Nervous System
9/12/11 First Lecture
25
Medical
Graduate
09/12/2011

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Cards

Term
What nervous system cells does the neural tube give rise to?
Definition
CNS Neurons and Macroglia
Term
What two types of cells constitute the CNS Macroglia?
Definition
Astrocytes and oligodendrocytes
Term
What nervous system cells do neural crest cells differentiate into?
Definition
PNS Neurons and Glia
Term
What embryologic structure gives rise to the ventricles of the CNS?
Definition
Neural tube
Term
What are the 4 types of glial cells, what part (CNS or PNS) do they play a role in, and what is their respective roles?
Definition
1. Oligodendrocytes - CNS, make myelin
2. Astrocytes - CNS, nutritive and supportive connections between capillaries and neurons
3. Microglia - CNS, phagocytes activated after injury
4. Schwann cells - PNS, make myelin and support non-myelinated cells

NOTE: There are also "Satellite" cells that play a role in supporting sensory ganglia in the PNS
Term
What embryonic layer gives rise to microglia?
Definition
mesoderm cells that migrate into the nervous sytem
Term
Which glial cell type plays a major role in the blood brain barrier?
Definition
Astrocytes
Term
What role do Schwann cells play in the PNS
Definition
Make myelin in the PNS and support non myelinated axons
Term
What role do Schwann cells play in the PNS
Definition
Make myelin in the PNS and support non myelinated axons
Term
What two major roles does the blood brain barrier play?
Definition
1. Layer of defense against pathogens

2. Maintains a homeostatic fluid environment in the cerebral spinal fluid
Term
What are the gaps between myelated Schwann cells called on axons?
Definition
Nodes of Ranvier
Term
What 2 roles do myelin play in conducting action potentials?
Definition
1. Electrical insulation

2. Speeds up conduction velocity
Term
How many axons can an oligodendrocyte myelate?
Definition
anywhere from 3-10
Term
What are the 4 signaling steps in an axon and where does each occur?
Definition
1. Input - dendrites and cell body
2. Summation - axon hillock
3. Conduction - axon
4. Output - axon terminal
Term
Where does protein synthesis happen in the axons?
Definition
Cell body
Term
What ion is most responsible for the resting potential of a nervous cell?
Definition
Potassium (Vrest is close to the Nernst potential for Potassium)
Term
Is the cytoplasmic environment of a cell negative or positively charged with respect to the extracellular space?
Definition
Negative
Term
Which equation yields the equilibrium membrane potential for a single ion?
Definition
Nernst
Term
The concentrations of the following ions are high in the intracellular or extracellular space: Na, K, Cl, Ca?
Definition
Na - extracellular
K - intracellular
Cl - extracellular
Ca - Extracellular
Term
The resting potential of a typical neural cell is approximately what?
Definition
Between -80 to -90 mV
Term
Which equation yields the equilibrium potential of a membrane with multiple ions present and how is this different from the Nernst equation?
Definition
1. Goldman-Hodgkin-Katz (no net ion flux at this potential)

2. The presence of multiple ions means that this equilibrium still has ion flux across the membrane at the equilibrium potential, and thus still requires energy to maintain this state, whereas the Nernst does not require any energy to maintain
Term
Ion permeability varies with respect to what variable in neural cells?
Definition
Membrane potential. This reflects the opening and closing of voltage gated ion channels in the cell membrane.
Term
What variable reflects the length of voltage spread down an axon from a location where current is injected into the axon?
Definition
Space constant
Term
What variable reflects how quickly or slowly a specific area of an axon response to the application of current?
Definition
Time constant
Term
What role did the voltage clamp play in the study of action potentials?
Definition
Allowed people to fix the membrane potential to a desired voltage, allowed the study of individual ionic currents and the role they played in the action potential
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