Neurons and Neural Circuits

<p>By regulating chemical concentrations and blood flow around neurons. (B)</p> Signup and view all the answers

<p>Acting as the primary immune cells to remove waste and pathogens. (B)</p> Signup and view all the answers

<p>Neural networks. (C)</p> Signup and view all the answers

<p>Sensory neuron → Interneuron → Motor neuron (B)</p> Signup and view all the answers

<p>Schwann Cells (B)</p> Signup and view all the answers

<p>Chloride (Cl⁻) (A)</p> Signup and view all the answers

<p>Increased levels of acetylcholine in the synapse (A)</p> Signup and view all the answers

<p>Serotonin (B)</p> Signup and view all the answers

<p>To restore the resting potential by pumping 3 Na⁺ out and 2 K⁺ in (A)</p> Signup and view all the answers

<p>Reuptake (A)</p> Signup and view all the answers

<p>Glutamate (D)</p> Signup and view all the answers

<p>By opening or closing in response to changes in membrane voltage (B)</p> Signup and view all the answers

<p>Dopamine (D)</p> Signup and view all the answers

<p>Polydendrocytes (NG2 cells) (B)</p> Signup and view all the answers

<p>Detecting and removing harmful substances, including pathogens and damaged cells (A)</p> Signup and view all the answers

<p>Cilia, which generate a current to circulate CSF (B)</p> Signup and view all the answers

<p>Secreting cerebrospinal fluid (CSF) (C)</p> Signup and view all the answers

<p>Hydrocephalus (C)</p> Signup and view all the answers

<p>Sodium (Na⁺) (C)</p> Signup and view all the answers

<p>K⁺ ions move out of the neuron during repolarization, helping restore the resting membrane potential. (D)</p> Signup and view all the answers

<p>Chronic inflammation and neuronal death (B)</p> Signup and view all the answers

<p>By hijacking the retrograde axonal transport system powered by dynein. (A)</p> Signup and view all the answers

<p>To increase the surface area available for synapse formation, enhancing connectivity. (C)</p> Signup and view all the answers

<p>Neurotransmitter receptors, signaling proteins, and scaffolding molecules. (B)</p> Signup and view all the answers

<p>The axon hillock integrates signals to determine whether to fire an action potential, while the initial segment is the site of action potential generation. (A)</p> Signup and view all the answers

<p>Schwann cells in the peripheral nervous system. (C)</p> Signup and view all the answers

<p>It increases conduction velocity by reducing ion leakage and allowing saltatory conduction. (B)</p> Signup and view all the answers

<p>Axon hillock. (C)</p> Signup and view all the answers

<p>Impaired learning and memory due to reduced synaptic plasticity. (B)</p> Signup and view all the answers

<p>To allow potassium ions to exit the neuron, making the inside more negative. (C)</p> Signup and view all the answers

<p>All voltage-gated sodium channels are either open or inactivated. (D)</p> Signup and view all the answers

<p>By allowing calcium to enter the neuron, triggering neurotransmitter release. (C)</p> Signup and view all the answers

<p>A stronger-than-usual stimulus is required to overcome the hyperpolarization and the remaining open potassium channels. (B)</p> Signup and view all the answers

<p>Both Na⁺ and K⁺ channels are closed. (B)</p> Signup and view all the answers

<p>It prevents further influx of Na⁺, leading to the end of the depolarization phase. (B)</p> Signup and view all the answers

<p>To ensure one-way signal transmission and regulate the frequency of nerve impulses. (B)</p> Signup and view all the answers

<p>Slow closing of $K^+$ channels. (C)</p> Signup and view all the answers

<p>Because ion channels must open and close at every point along the axon. (D)</p> Signup and view all the answers

<p>It provides insulation, allowing the action potential to jump between Nodes of Ranvier. (A)</p> Signup and view all the answers

<p>To store and release neurotransmitters into the synaptic cleft. (D)</p> Signup and view all the answers

<p>Myelinated motor neurons where rapid responses are necessary. (C)</p> Signup and view all the answers

<p>A large-diameter, myelinated axon. (C)</p> Signup and view all the answers

<p>Dense-core vesicles are larger and store neuropeptides. (A)</p> Signup and view all the answers

<p>A larger diameter increases speed by reducing resistance to ion flow. (B)</p> Signup and view all the answers

<p>Pain and autonomic neurons where speed is less critical. (A)</p> Signup and view all the answers

The fundamental unit of the nervous system that transmits signals.

Neurons consist of dendrites, cell body, and axon.

Extensions of neurons that receive signals from other neurons.

Processes the signals received by dendrites.

A long projection that transmits signals to other neurons or muscles.

A group of interconnected neurons that work together to process information.

Non-neuronal cells providing support to neurons in the nervous system.

Include astrocytes, oligodendrocytes, Schwann cells, and microglia.

A motor protein that powers transport in neurons.

Small protrusions on dendrites where synapses form, enhancing connections.

Protein-rich structures on the postsynaptic side of a synapse, crucial for synaptic strength.

Cone-shaped junction where a neuron decides to fire an action potential.

The start of the axon where action potentials are generated, rich in Na⁺ channels.

Fatty sheath around axons that increases the speed of electrical signals.

Glial cells in the CNS, also known as NG2 cells, that can develop into oligodendrocytes.

Immune cells of the CNS that detect and remove harmful substances.

Glial cells lining the ventricles that produce and regulate cerebrospinal fluid (CSF).

Fluid produced by ependymal cells that cushions the brain and spinal cord.

Condition caused by dysfunction in ependymal cells leading to excess CSF accumulation.

Flow of charged particles across a neuron's membrane, crucial for electrical signals.

Electrical signals generated by ion movements in neurons.

Sodium (Na⁺) and Potassium (K⁺) are essential for generating electrical signals in neurons.

Channels that open or close based on membrane voltage, selective for ions like Na⁺, K⁺, Ca²⁺.

Channels that open during depolarization, allowing Na⁺ to flow into the neuron.

Stage where the neuron's membrane potential becomes less negative, reaching ~ -55mV.

When the neuron's membrane potential reaches around +30mV, Na⁺ channels inactivate and K⁺ channels open.

Stage where the membrane potential becomes more negative again as K⁺ leaves the neuron.

Stage when the neuron's membrane potential drops to ~ -80mV, becoming more negative than resting state.

Time during which no new action potential can be triggered, regardless of stimulus strength.

Period after the absolute refractory period when stronger stimuli can trigger an action potential due to hyperpolarization.

Moves into the neuron, making it more negative.

Essential for neurotransmitter release at synapses.

Channels that open or close in response to voltage changes.

Channels that open when neurotransmitters bind.

Restores resting potential by pumping Na⁺ out and K⁺ in.

Increase neuronal activity, like glutamate and acetylcholine.

Decrease neuronal activity, like GABA and glycine.

Processes that remove neurotransmitters from the synapse.

Transmission of action potentials along unmyelinated axons where every segment depolarizes sequentially.

Fast transmission of action potentials in myelinated axons by jumping between Nodes of Ranvier.

Elements that influence how fast action potentials travel, including axon diameter and myelination.

Larger axons conduct signals faster due to lower resistance and easier ion flow.

Presence of a fatty layer around axons that enhances conduction speed by enabling saltatory conduction.

Small membrane-bound sacs in cells that store and transport substances like neurotransmitters.

Vesicles located in axon terminals that store and release neurotransmitters during synaptic transmission.

Larger vesicles that store neuropeptides, used for signaling in the nervous system.