PSYC234 2.1 Neural Activity B + 2.2 Neural Activity C Flashcards
(24 cards)
What is an action potential?
Transmits information without loss of intensity over distance
Action potentials are essential for communication within the nervous system.
What is the cost of action potentials?
Delay between stimulus and its arrival in the brain
This delay can affect reaction times.
What is the charge of a resting neuron inside compared to the outside?
Negative charge
This is due to negatively charged proteins inside the neuron.
What does the sodium-potassium pump do?
Moves sodium ions out of neuron and potassium ions in
This process is crucial for maintaining the resting membrane potential.
What happens when the membrane is at rest?
Electrical gradient and concentration gradient drive sodium ions into the cell, but gates are closed
Potassium ions have a slight tendency to leave the cell.
What is the all-or-none law?
Any stimulus greater than the threshold results in action potential amplitude and velocity being independent of the stimulus size
This means action potentials either occur fully or not at all.
What occurs when the membrane is depolarized enough to reach the cell’s threshold?
Sodium and potassium channels open, sodium ions enter rapidly
This process reduces and reverses the charge across the membrane.
What happens after the peak of action potential?
Membrane returns to its original level of polarization due to outflow of potassium ions
This is essential for the neuron to be ready for the next action potential.
How is an action potential regenerated along the axon?
Sodium ions flow through the core of the axon, stimulating the next point to its threshold
This allows for the action potential to maintain constant magnitude.
What is the refractory period?
Period immediately after action potential where the membrane is resistant to starting another action potential
This is crucial for ensuring action potentials are discrete events.
Where do action potentials form in myelinated axons?
Only in nodes between myelinated segments
This leads to faster transmission.
What is a synapse?
Point of communication between neurons
Synapses are critical for neuronal communication.
What is temporal summation?
Combining of graded potentials from stimuli at different times
This affects the overall response of the neuron.
What is spatial summation?
Combining of potentials from different locations
This helps determine whether the neuron will fire an action potential.
What is an EPSP?
Excitatory graded potential (depolarization)
EPSPs increase the likelihood of a neuron firing an action potential.
What is an IPSP?
Inhibitory graded potential (hyperpolarization)
IPSPs decrease the likelihood of a neuron firing an action potential.
What types of chemicals are most commonly used at synapses?
Amino acids or chemicals derived from them
These neurotransmitters play a key role in synaptic transmission.
What happens when an action potential opens calcium channels in the axon terminal?
Calcium enables release of neurotransmitters
This is a critical step in neurotransmission.
What are ionotropic synapses?
Neurotransmitter attaches to receptor, opening gates to allow a particular ion to cross the membrane
They produce fast and brief effects.
What neurotransmitter is most commonly used for excitatory synapses?
Glutamate
This neurotransmitter is key for synaptic excitation.
What is the role of neuromodulators?
Activate metabotropic receptors to produce slower but longer-lasting changes
They have broader effects compared to ionotropic synapses.
What is re-uptake?
Transmitter molecules re-enter presynaptic cell via transporter molecules in membrane
This process allows recycling of neurotransmitters.
What effect do stimulants and antidepressants have on neurotransmitters?
Inhibit reuptake of certain transmitters
This can enhance the effects of neurotransmitters in the synaptic cleft.
True or False: Most people use only a small part of their brain.
False
People use all of their brain.
