Week 4 Flashcards
What is the small region between neurons called?
SYNAPSE
The synapse is crucial for neural communication.
What are neurotransmitters?
Messenger chemicals released by a neuron onto a target
They cause excitatory or inhibitory effects.
What do EPSP and IPSP stand for?
Excitatory Post-Synaptic Potential and Inhibitory Post-Synaptic Potential
EPSPs lead to depolarization while IPSPs lead to hyperpolarization.
What is the presynaptic terminal?
Axon terminal from input (stimulating) presynaptic neuron
It synapses with a dendritic spine of a postsynaptic neuron.
Where are neurotransmitters synthesized?
In the cell body or the axon terminal from mRNA and food building blocks
Some neurotransmitters are synthesized according to DNA instructions.
What are synaptic vesicles?
Structures loaded with neurotransmitters
They must dock on the presynaptic membrane to release neurotransmitters.
What triggers the release of neurotransmitters?
Influx of Ca+2 into the axon terminal
This occurs when action potentials open voltage-sensitive Ca+2 channels.
What happens when a neurotransmitter binds to an ionotropic receptor?
An ion channel opens within the receptor itself
This allows ions to flow across the membrane.
What is an excitatory neurotransmitter?
A neurotransmitter that causes depolarization
This increases the likelihood of firing an action potential.
What is an inhibitory neurotransmitter?
A neurotransmitter that causes hyperpolarization
This decreases the likelihood of firing an action potential.
What is the difference between graded potentials and action potentials?
Graded potentials are variable and can decay; action potentials are all-or-none
EPSPs and IPSPs are types of graded potentials.
What is the initial segment in a neuron?
An area near the axon hillock rich in voltage-sensitive channels
This area is crucial for initiating action potentials.
What does spatial summation refer to?
The integration of signals from multiple synapses
It determines the overall effect on the postsynaptic neuron.
What is temporal summation?
The integration of signals from one synapse over time
It also influences the postsynaptic neuron’s response.
How do psychoactive drugs affect neurotransmission?
By influencing ongoing chemical activities at synapses
They can act as agonists or antagonists.
What is the blood-brain barrier?
A protective barrier that prevents many substances from entering the brain
It maintains ion balance and protects against toxins.
What role do astrocytes play in the nervous system?
Provide structural support and maintain the blood-brain barrier
They facilitate nutrient exchange between blood vessels and neurons.
What is L-DOPA used for?
As a drug therapy for Parkinson’s disease
It is a precursor to dopamine that can cross the blood-brain barrier.
Fill in the blank: Neurotransmitters can _______ or _______ neuron activity.
[excite, inhibit]
This modulation is crucial for neural communication.
True or False: Action potentials can vary in magnitude.
False
Action potentials are all-or-none events.
