Biology and Neuroscience - Will Flashcards
What are the two types of cells in the nervous system?
Neurons and Glial cells
Where are dendrites located?
They are extensions of the cell body membrane.
What proteins are bound to the dendrites?
Receptors
What are the molecules called that bind to receptors on the dendrites?
Neurotransmitters
What two parts of a neuron work together to send messages?
The axon and the soma.
What is the cell body of a neuron called?
The soma.
What are the “dendrite looking” structures at the end of the axon? What is located at the end of them?
Axon Terminals, terminal buttons
What are vesicles in the axon?
They are little bubbles that contain neurotransmitters.
What structures interact between the presynaptic vs postsynaptic neuron? What separates them?
The presynaptic terminal button is separated from the postsynaptic dendrite by the synaptic cleft.
Where do neurotransmitters bind?
Postsynaptic receptors
What structure surrounds the axon and acts as insulation?
The myelin sheathe.
What are the breaks in the myelin sheathe called? What are they there for?
The nodes of Ranvir allow for ions to enter and charge the inside of the cell, leading to more efficient signal transmission.
What are the three important ions in the process of neural signal transmission? (indicate charges)
Potassium (K+)
Chloride (Cl-)
Sodium (Na+)
What is the charge of a polarized ion? Will it fire in this state?
Around -70mV. It is less likely to fire.
When will a neuron be more likely to fire?
When the inside of a neuron gets more positively charged farther away from polarization.
What structure in the neurons allow for ions to move in and out of the cell?
The channels.
What ion is introduced into the cell to induce an action potential?
Sodium
What are the states of voltage gated channels determined by?
The voltage of the neuron.
What is the propagation process responsible for?
Bringing the electric impulse to the end of the neuron.
What happens when an electrical impulse reaches the end of a neuron?
Neurotransmitters are released.
At resting stage, what is the state of the voltage controlled gates? What is the Na/K transporter doing?
The Na gates are are closed and most of the K gates are closed. The Na/K transporter is pumping Na out of the neuron and K in.
What ions enter the cell in response to depolarization? What threshold does this lead to?
Na+ ions enter the cell as the voltage gates open. This brings the cell closer to the threshold of excitation.
What happens at the threshold of excitation?
All Na channels open.
What happens during the peak action potential?
The Na channels close and the K channels open, releasing K ions into the extracellular fluid. The cell becomes hyperpolarized.
What are the 5 stages of the action potential? Lightly describe them.
- Threshold- Enough Na ions enter the cell, triggering the opening of voltage gated Na channels.
- Depolarization- At the nodes of Ranvir, the charge inside the axon is higher than the surrounding extracellular fluid.
- Repolarization - Na channels close, and K channels open allowing K ions out of the cell. This brings the charge of the cell down closer to its polarized state.
- Refractory period - The K channels stay open long enough for the cell to become hyperpolarized (too negative).
- Resting state - The neuron stabilizes at its resting polarity.
What is the difference between excitatory and inhibitory neurotransmitters?
Excitatory neurotransmitters increase the probability of the neuron firing and inhibitory ones do the opposite.
What does the synapse encompass?
The presynaptic terminal button, the postsynaptic dendrite, and the synaptic cleft.
What is an agonist drug?
It is a drug that mimics the action of a neurotransmitter produced by the body.
What is the name of a neurotransmitter naturally produced by the body?
An endogenous neurotransmitter.
What is an antagonist drug? What are the two types of them?
A drug that inhibits the action of the endogenous transmitter. Two types of antagonist drug are competitive and non-competitive.
What is the difference between a competitive and non-competitive antagonist?
A competitive antagonist binds to the same receptor as the endogenous neurotransmitter, non-competitive (passive-aggressive) ones bind to other receptor sites but still inhibit receptor function in a way.
What is a partial agonist/antagonist?
A drug that binds to a receptor site for less time, being less effective.
What kind of neurotransmitter is glutamate? What is it responsible for?
It is excitatory and responsible for learning and movement.
What kind of neurotransmitter is GABA? What is it responsible for?
It is inhibitory and related to learning and anxiety regulation.
What kind of neurotransmitter is acetylcholine? What is it responsible for?
It is excitatory and responsible for learning and muscle action.
What kind of neurotransmitter is dopamine? What is it responsible for?
It is excitatory and inhibitory. It is responsible for learning and reward systems.
What kind of neurotransmitter is seratonin? What is it responsible for?
It is excitatory and inhibitory. It is responsible for mood regulation.
What kind of neurotransmitter is norepinephrine? What is it responsible for?
It is excitatory and inhibitory. It is responsible for mood regulation.
What kind of neurotransmitters are endorphins and enkephalins? What are they responsible for?
They are excitatory and inhibitory. They are responsible for pain regulation.
What kind of cell is most common in the nervous system?
Glial cells.
What four functions do glial cells carry out?
- Structural support
- Waste removal/dead neuron removal
- Nutrient provision
- Speeding up electrical impulses.
What is the function of ogliodendrocytes?
They wrap the axons of the central nervous system with the myelin sheathe.
What cells are responsible for the myelin sheathes of neurons outside the central nervous system?
Schwann Cells
What glial cells are involved in the immune function of the brain?
astrocytes and microglia