Neuron Overview and Signal Transmission

To detect and transmit sensory stimuli to the nervous system.

Graded potentials vary in magnitude and can be depolarizing or hyperpolarizing, whereas action potentials are all-or-nothing and have a fixed amplitude.

To transmit signals across the synaptic cleft to adjacent neurons or target cells.

<p>Action potentials allow for the rapid transmission of electrical signals along the axon to communicate with other neurons or muscles.</p> Signup and view all the answers

<p>They propagate unidirectionally due to the refractory period that follows the depolarization, preventing the signal from traveling backward.</p> Signup and view all the answers

<p>Neuroglia support and protect neurons, maintaining homeostasis and forming myelin sheaths around axons.</p> Signup and view all the answers

<p>Synapses allow for communication between neurons, enabling the formation of complex circuits that process information.</p> Signup and view all the answers

<p>Muscle stretch receptors provide feedback about muscle length and tension, aiding in proprioception and reflex actions.</p> Signup and view all the answers

<p>The influx of Na+ is extremely rapid due to a large concentration gradient and a strong electrical gradient.</p> Signup and view all the answers

<p>Na+ channels close at the peak of the action potential, which is +30 mV.</p> Signup and view all the answers

<p>The efflux of K+ is rapid because of a large K+ concentration gradient and a significant electrical gradient.</p> Signup and view all the answers

<p>The Na+/K+ pump helps reset the resting membrane potential (RMP) back to -70 mV.</p> Signup and view all the answers

<p>Action potentials propagate in one direction due to the refractory period of the previously depolarized section of the axon.</p> Signup and view all the answers

<p>Muscle stretch receptors detect changes in muscle length, providing information about the internal environment.</p> Signup and view all the answers

<p>Neurotransmitters are released by sensory cells when activated, triggering graded potentials in adjacent neurons.</p> Signup and view all the answers

<p>Graded potentials are localized changes in membrane potential, while action potentials are rapid, large-scale changes that propagate along axons.</p> Signup and view all the answers

<p>Neurotransmitters diffuse across the synaptic cleft and bind to specific receptors on the postsynaptic cell.</p> Signup and view all the answers

<p>An increase in stimulus strength leads to a greater increase in membrane potential, resulting in stronger graded potentials.</p> Signup and view all the answers

<p>Larger diameter axons allow for faster transmission of action potentials due to reduced resistance to ion flow.</p> Signup and view all the answers

<p>Sensory cells detect environmental stimuli and convert them into electrical signals for transmission to the nervous system.</p> Signup and view all the answers

<p>Ion channels facilitate the movement of ions across nerve cell membranes, crucial for generating action potentials.</p> Signup and view all the answers

<p>Graded potentials in the cell body are created by synaptic inputs from dendrites that alter the membrane potential.</p> Signup and view all the answers

<p>Sensory systems employ specialized receptor cells that respond to specific stimuli, such as sweet, salty, or light.</p> Signup and view all the answers

<p>The binding of a ligand, such as sugar, a drug, or a hormone, to the channel initiates the opening of ligand-gated Na+ channels.</p> Signup and view all the answers

<p>The influx of Na+ causes the membrane potential to increase rapidly, resulting in depolarization.</p> Signup and view all the answers

<p>The activation leads to a rapid influx of Na+, which generates a graded potential.</p> Signup and view all the answers

<p>Ligand-gated channels open in response to specific molecules binding to them, while voltage-gated channels open in response to changes in membrane potential.</p> Signup and view all the answers

<p>Na+ ions contribute to the depolarization of the cell when they rush in, creating a graded potential.</p> Signup and view all the answers

<p>Before Na+ ions enter, the membrane potential is generally at a resting level around -70 mV.</p> Signup and view all the answers

<p>When a hormone binds to the ligand-gated Na+ channels, it triggers the opening of these channels, leading to changes in sensory perception through graded potentials.</p> Signup and view all the answers

<p>The primary effect of depolarization in sensory cells is the generation of action potentials or graded potentials, which convey sensory information.</p> Signup and view all the answers

<p>The influx of Na+ primarily causes depolarization, while Ca2+ influx is often involved in signaling pathways and neurotransmitter release.</p> Signup and view all the answers

<p>The rapid increase in membrane potential is critical for transmitting signals quickly and efficiently within the nervous system.</p> Signup and view all the answers

<p>The ligand binds to the channel, causing the ligand-gated Na+ channel to open, which allows Na+ to rush into the cell.</p> Signup and view all the answers

<p>The increased membrane potential activates the voltage-gated Ca2+ channels, leading to Ca2+ rushing into the cell.</p> Signup and view all the answers

<p>Ca2+ diffuses across the entire cell and causes neurotransmitter vesicles to fuse with the presynaptic membrane and release their contents into the synapse.</p> Signup and view all the answers

<p>The sensory cell generates graded potentials that lead to the release of neurotransmitters in response to the stimulus.</p> Signup and view all the answers

<p>If the membrane potential reaches -55 mV, action potentials are generated and propagated along the axon.</p> Signup and view all the answers

<p>A larger stimulus can maintain the threshold of -55 mV, resulting in a high frequency of action potentials.</p> Signup and view all the answers

<p>NT receptors are ligand-gated Na+ channels that, upon binding neurotransmitters, facilitate Na+ influx into the post-synaptic cell.</p> Signup and view all the answers

<p>A nerve impulse travels when the membrane potential reaches the threshold of -55 mV.</p> Signup and view all the answers

<p>The nerve impulse travels in one direction due to the refractory period in the previously depolarized segment of the axon.</p> Signup and view all the answers

<p>Graded potentials contribute to the membranous changes that can generate action potentials if the threshold is reached.</p> Signup and view all the answers