Nervous System - Checking in

During depolarization, which ions flow into the neuron, causing the inside to become more positive?

• Sodium (Na+)

• Potassium (K+)

• Chloride (Cl-)

• Calcium (Ca2+)

How does the action potential propagate along the axon of a neuron?

• By passive flow of ions only

• By active transport of ions

• By sequential opening of voltage-gated ion channels

• By diffusion of neurotransmitters

What happens during repolarization of a neuron's membrane?

• Sodium ions (Na+) flow out of the neuron

• Potassium ions (K+) flow into the neuron

• Potassium ions (K+) flow out of the neuron

• Sodium ions (Na+) flow into the neuron

What is hyperpolarization in the context of neuronal action potentials?

• The membrane potential becomes more positive than the resting potential

• The membrane potential returns to the resting potential

• The membrane potential becomes more negative than the resting potential

• The membrane potential reaches the threshold potential

Which ion channel's opening is primarily responsible for the rapid depolarization phase of the action potential?

• Sodium (Na+) channels

• Potassium (K+) channels

• Calcium (Ca2+) channels

• Chloride (Cl-) channels

What is the role of the sodium-potassium pump in maintaining the resting membrane potential of a neuron?

• It pumps sodium ions out and potassium ions into the neuron, against their concentration gradients.

• It allows sodium and potassium ions to flow down their concentration gradients.

• It equalizes the concentrations of sodium and potassium ions inside and outside the neuron.

• It generates action potentials by rapidly changing the permeability of the membrane to sodium and potassium.

Imagine a busy network of communication where messages are constantly being sent back and forth. What is the significance of the refractory period in this network's 'neuronal action potentials' to ensure efficient message delivery?

• It allows the network to send messages at a higher frequency.

• It prevents the backward propagation of messages, ensuring they only move forward.

• It increases the speed of message delivery along the network.

• It decreases the network's threshold for sending messages.

Draw and label the elements a cow needs to detect pain and pressure when you push on its leg.

Answer explanation

Drawing should including:

Sensory Neuron

Motor Neuron

Spinal Cord

Brain

Mechano and nociceptors

interneuron

action potential

synaptic transmission

arrow depicting the travel distance

What is the primary function of myelin sheath in neuronal transmission?

• To decrease the speed of action potentials

• To increase the permeability of the neuron membrane to ions

• To insulate the axon and increase the speed of action potentials

• To facilitate the diffusion of neurotransmitters across the synaptic cleft

What role do voltage-gated calcium channels play in neurotransmitter release at the synaptic cleft?

• They initiate the repolarization of the neuron.

• They directly trigger the release of neurotransmitters into the synaptic cleft.

• They decrease the membrane potential to prevent neurotransmitter release.

• They replenish the neuron with calcium ions to prepare for the next action potential.