Week 2 Flashcards
The resting potential of a neuron
-70mV difference between inside and outside of cell
Concentration of ions inside and outside a cell at resting state
High concentration of sodium ions outside cell, high concentration of potassium ions inside cell
Steps involved in an action potential
- Depolarising stimulus of +15mV (raising it to -55mV) at axon hillock
- Sodium rushes into cell, potassium channels open, sodium channels close
- Potassium rushes out of cell, potassium channels close
- Refractory period
How are ions charged
Electrons are negatively charged; so an absence of electrons = positively charged. A surplus of electrons = negatively charged
Sodium
Na+
Potassium
K+
Calcium
Ca2+
Chloride
Cl-
Organic
A-
Steps involved in an action potential
- Depolarising stimulus of +15mV (raising it to -55mV) at axon hillock
- Sodium rushes into cell, potassium channels open, sodium channels close
- Potassium rushes out of cell, potassium channels close
- Refractory period
Organic
A-
Sodium Potassium Pump
3 sodium ions out for every 2 potassium ions in (ie continuously exchanges three intracellular Na+ for two K+)
Sodium Potassium Pump
3 sodium ions out for every 2 potassium ions in
Diffusion Forces
Particles move away from areas of high concentration
Electrostatic Forces
Like charges repel each other
Threshold Potential
Typically voltage inside the neuron becomes more positive by about +15mV (making the charge (-55mV), triggering an action potential
Voltage at peak of action potential
+30mV
Exocytosis
The process by which neurotransmitters are released into the synapse
What is white matter made of?
Myelinated axons
What is grey matter made of?
Cell bodies
What is grey matter made of?
Cell bodies
All or none law
Once an action potential is triggered, it is always the same size. The threshold potential being reached is the catalyst for an action potential
Direct agonist
Drug that binds with and activates a receptor
Receptor blocker
A drug that binds with a receptor but does not activate it prevents the natural ligand from binding with the receptor (antagonist)
Direct antagonist
Synonym for Receptor Blocker
Noncompetitive binding
Binding of a drug to a site on a receptor; does not interfere with the binding site for the principal ligand
Indirect antagonist
A drug that attaches to a binding site on a receptor and interferes with the action of receptor, but without interfering with the binding of the principal ligand
Indirect agonist
A drug that attaches to a binding site on a receptor and facilitates the action of the receptor; does not interfere with binding site of principal ligand
EPSP
Excitatory Post Synaptic Potential - Causes cell to become more positive
IPSP
Inhibitory Post Synaptic Potential - Causes cell to become more negative
Voltage during refractory period
Gets down to -80mV
Presynaptic Inhibition
Receptors on the axonal endings that inhibit exocytosis, rather than inhibiting the postsynaptic neuron (GABA does this by stopping inflow of calcium at the axon terminal)
Ionotropic Receptors
Same molecular unit for receptor and ion channel
Metabotropic Receptors
Receptor activates a G Protein, instigating a number of intracellular chemical processes involving second messengers (opens many ion channels from ‘inside’ the neuron)
Astrocytes
Star-shaped glial cells. Support neurons and provide structure. Form the blood-brain barrier.
Astrocytes
Star-shaped glial cells. Support neurons and provide structure. Form part of the blood-brain barrier.
Oligodendrocyte
Glial cells that wrap around CNS neurons to provide myelin sheath
Swann Cells
Glial cells that wrap around PNS neurons to provide myelin sheath
Swann Cells
Glial cells that wrap around PNS neurons to provide myelin sheath
Function of a neuron
Encoding memories; production of thoughts and memories; the production of neurotransmitters
Nerve impulse describes:
The movement of an action potential along the axon
Dendrites receive what sort of input? Inhibitory or excitatory?
Both
Saltatory conduction
At each node of ranvier, the action potential is amplified to original intensity
What is common of the postsynaptic membrane
Thickened appearance and receptor protiens
Spatial summation
multiple inputs from multiple neurons adding up to trigger action potential
Temporal summation
lots of signals from one neuron in quick succession, triggering an action potential
What is common of the postsynaptic membrane?
Thickened appearance and receptor protiens
Temporal summation
lots of signals from one neuron in quick succession, triggering an action potential
The influx of what ions at the Synaptic Terminal causes exocytation?
Ca++; Calcium
Where are neurotransmitters produced?
In the soma and synaptic terminals
Where are neurotransmitters produced?
In the soma and synaptic terminals
Acetylcholine is the classical neurotransmitter for:
All skeletal motor synapses
