6.2.2 Nerve Impulse Transmission

• What is a nerve impulse?

  An electrical signal
• Depolarization occurs when Na+ ions enter the neuron.


  True
• What role do ion channels play in nerve impulse transmission?

  Regulate ion flow
• The myelin sheath insulates the axon, allowing faster transmission
• A neuron's dendrites receive signals from other neurons
• Arrange the steps of repolarization in the correct sequence:

  1️⃣ K+ channels open

  2️⃣ K+ ions diffuse out

  3️⃣ Membrane potential returns to -70 mV
• What is the fundamental unit of the nervous system responsible for transmitting nerve impulses?

  Neuron
• The axon transmits nerve impulses away from the cell body to other neurons or effector organs.


  True
• What maintains the resting membrane potential of a neuron?

  Sodium-potassium pump
• What is the approximate value of the resting membrane potential in a neuron?

  -70 mV
• Stages of depolarization in a neuron:

  1️⃣ Resting membrane potential (-70 mV)

  2️⃣ Stimulus triggers Na+ channels to open

  3️⃣ Na+ ions rush in, reversing potential

  4️⃣ Membrane potential reaches +40 mV
• What is the threshold potential typically required to trigger an action potential?

  -55 mV
• Stages of nerve impulse transmission in a neuron:

  1️⃣ Resting membrane potential

  2️⃣ Depolarization

  3️⃣ Repolarization

  4️⃣ Refractory period
• Which ion is primarily responsible for repolarization?

  K+
• The action potential is triggered when the membrane potential reaches a threshold potential of approximately -55 mV.
• Match the ion channel with its role:

  Voltage-gated Na+ Channels ↔️ Open during depolarization

  Voltage-gated K+ Channels ↔️ Open during repolarization
• Neurotransmitters bind to receptors on the postsynaptic neuron to trigger a response.

  True
• The myelin sheath insulates the axon, allowing faster nerve impulse transmission.


  True
• The membrane is more permeable to K+ than Na+ during the resting state.


  True
• Depolarization is essential for nerve impulse transmission.


  True
• The repolarization process restores the membrane potential to its resting state.

  True
• The action potential is triggered when the membrane potential reaches a certain threshold
• Voltage-gated Na+ channels open when the threshold potential is reached

  True
• Match the ion channel with its function:

  Voltage-gated Na+ channels ↔️ Allow Na+ influx during depolarization

  Voltage-gated K+ channels ↔️ Allow K+ efflux during repolarization
• The presynaptic neuron releases neurotransmitters into the synaptic cleft


  True
• An inhibitory postsynaptic potential (IPSP) hyperpolarizes the postsynaptic membrane, making it more negative
• A neuron is the fundamental unit of the nervous system
• Arrange the stages of nerve impulse transmission in the correct order:

  1️⃣ Resting membrane potential

  2️⃣ Depolarization

  3️⃣ Repolarization
• Synapses transmit nerve impulses electrically.

  False
• What is the role of the sodium-potassium pump in maintaining the resting membrane potential?

  Maintains ion gradients
• What happens to the membrane potential during depolarization?

  Reverses from -70 mV to +40 mV
• Which ion is primarily responsible for repolarization?

  Potassium (K+)
• The cell body of a neuron is also known as the soma
• What is the primary function of the myelin sheath in a neuron?

  Insulates the axon
• Na+ ions are at a higher concentration inside the neuron during resting membrane potential.

  False
• Depolarization occurs when Na+ ions enter the neuron, making the membrane potential less negative.

  True
• What triggers the opening of voltage-gated K+ channels during repolarization?

  +40 mV
• During an action potential, the membrane potential reverses from -70 mV to +40 mV.


  True
• What is the membrane potential of a neuron in its resting state?

  -70 mV
• Order the stages of an action potential:

  1️⃣ Resting

  2️⃣ Depolarization

  3️⃣ Repolarization

  4️⃣ Refractory Period