Nervous System and Electrical Signals

Comprehensive flashcards covering key concepts of the nervous system and electrical signals as outlined in the notes.

What is the resting membrane potential of a neuron?

-70mV

What role do ion leak channels play in neurons?

They contribute to the difference in ion concentrations across the membrane during resting membrane potential.

How many times more K+ leak channels are there compared to Na+ channels?

There are 50 to 100 times more K+ leak channels than Na+ leak channels.

What does the sodium-potassium pump do?

It actively transports K+ into the cell and Na+ out of the cell to maintain resting membrane potential.

What percentage of ATP does the sodium-potassium pump consume in neurons?

70% of the ATP in a neuron.

What are action potentials and how do they function in nerve cells?

Action potentials are changes in membrane potential that allow nerve cells to communicate with other cells.

What happens when a stimulus is applied to a nerve cell?

Chemically gated Na+ channels open briefly, allowing Na+ to diffuse into the cell.

What occurs if depolarization reaches a threshold value?

Voltage-gated Na+ channels open, leading to a significant increase in membrane permeability to Na+.

What is hyperpolarization?

A brief condition where the inside of the cell becomes more negative than the resting membrane potential.

What is the 'all-or-none' principle in action potentials?

If the threshold is reached, an action potential occurs; if not, no action potential occurs.

How is action potential conduction different in myelinated vs unmyelinated axons?

Myelinated axons use saltatory conduction and are faster, while unmyelinated axons use continuous conduction and are slower.

What is the structure of a neuroneuronal synapse?

A junction where one neuron's axon interacts with another neuron's membrane, including presynaptic terminals and postsynaptic membranes.

What triggers neurotransmitter release at the presynaptic terminal?

The opening of voltage-gated Ca2+ channels and influx of Ca2+ into the cell.

What determines the response of the postsynaptic membrane to neurotransmitters?

The type of neurotransmitter and the receptor type on the postsynaptic membrane.

What are some examples of neurotransmitters?

Acetylcholine and norepinephrine.

How are neurotransmitters cleared from the synaptic cleft?

They are rapidly broken down by enzymes or transported back into the presynaptic terminal.

What enzyme breaks down acetylcholine?

Acetylcholinesterase.

What happens to norepinephrine after it is released?

It is either actively transported back into the presynaptic terminal or broken down by enzymes.