Neurobiology Synaptic Transmission Quiz

The myelin sheath insulates the axon, preventing ion leakage and allowing the nerve impulse to jump between nodes of Ranvier.

In continuous conduction, there are no myelin sheaths, causing the nerve impulse to travel along the entire length of the axon without jumping.

The nodes of Ranvier are gaps in the myelin sheath where action potentials are generated, enabling the impulse to jump and speed up transmission.

<p>Saltatory conduction conserves energy by decreasing ion exchange, reducing the work required by Na⁺/K⁺ pumps to maintain resting potential.</p> Signup and view all the answers

<p>Voltage-gated Na⁺ channels open upon the arrival of an action potential, causing depolarization in the axon terminal.</p> Signup and view all the answers

<p>Voltage-gated Ca²⁺ channels open, allowing Ca²⁺ to enter the cell, which triggers vesicles to fuse with the presynaptic membrane to release neurotransmitters.</p> Signup and view all the answers

<p>A single vesicle usually contains about 10,000 acetylcholine (ACh) molecules.</p> Signup and view all the answers

<p>Vesicles release neurotransmitters via exocytosis after fusing with the presynaptic membrane.</p> Signup and view all the answers

<p>They allow strong Na⁺ influx and weak K⁺ efflux, leading to membrane depolarization and the generation of graded potentials.</p> Signup and view all the answers

<p>ACh is broken down by the enzyme acetylcholinesterase (AChE), which stops the influx of ions and ends the depolarization.</p> Signup and view all the answers

<p>Summation combines excitatory and inhibitory postsynaptic potentials (EPSPs and IPSPs) to influence whether an action potential is triggered.</p> Signup and view all the answers

<p>Spatial summation involves multiple presynaptic neurons releasing neurotransmitters simultaneously, while temporal summation involves a single presynaptic neuron releasing neurotransmitters rapidly in succession.</p> Signup and view all the answers

<p>If strong enough, it spreads to areas with voltage-gated Na⁺ channels, leading to the generation of an action potential.</p> Signup and view all the answers

<p>The products are choline and acetate, which are taken up by the presynaptic neuron to resynthesize ACh.</p> Signup and view all the answers

<p>Voltage-gated Na⁺ channels open in response to membrane depolarization, allowing Na⁺ influx that initiates the action potential.</p> Signup and view all the answers

<p>The body uses mechanisms like the threshold potential and graded potentials to determine if an action potential is triggered and its strength.</p> Signup and view all the answers

<p>The main components of the nervous system are the central nervous system, which includes the brain and spinal cord, and the peripheral nervous system, which consists of all nerves and sensory structures outside the CNS.</p> Signup and view all the answers

<p>The autonomic nervous system controls involuntary functions like gland activity and smooth muscle operation, while the somatic nervous system is responsible for voluntary control of skeletal muscles.</p> Signup and view all the answers

<p>The two subdivisions are the sympathetic nervous system, which prepares the body for 'fight or flight' responses, and the parasympathetic nervous system, which promotes 'rest and digest' functions.</p> Signup and view all the answers

<p>Centralization is the process where nerve cells are concentrated in specific regions to form central processing areas like the brain and spinal cord, leading to more organized and efficient signal processing.</p> Signup and view all the answers

<p>Cephalization is the evolutionary trend where sensory organs and nerve cells are concentrated at the front of the organism, forming a distinct head region that facilitates enhanced perception and processing of environmental information.</p> Signup and view all the answers

<p>More complex organisms possess centralized nervous systems that allow for better coordination and processing, unlike simpler organisms, which may have decentralized nerve nets without central processing areas.</p> Signup and view all the answers

<p>Central processing areas, such as the brain and spinal cord, play a crucial role in processing sensory information and coordinating responses, thus enhancing the efficiency of the nervous system.</p> Signup and view all the answers

<p>The emergence of a central nervous system allows for focused processing of stimuli, enabling quicker reaction times and more complex behaviors, which enhances survival and adaptability.</p> Signup and view all the answers

<p>They mimic neurotransmitters, leading to overstimulation of the postsynaptic neuron.</p> Signup and view all the answers

<p>Antagonists bind to receptors and block neurotransmitters from binding, thus reducing their effects.</p> Signup and view all the answers

<p>Neurotoxins disrupt normal neuron function, which can lead to cell death or dysfunction.</p> Signup and view all the answers

<p>Agonists promote neuron signaling by mimicking neurotransmitters, while antagonists inhibit signaling by blocking receptor activity.</p> Signup and view all the answers

<p>It is crucial for creating antidotes and effective treatments for poisoning and related conditions.</p> Signup and view all the answers

<p>It indicates an increase in behavioral complexity and adaptability to the environment.</p> Signup and view all the answers

<p>Vertebrates show significant development of the forebrain, which is crucial for cognition and sensory integration.</p> Signup and view all the answers

<p>Sensory neurons transmit impulses to the CNS, motor neurons carry signals from the CNS to effectors, and relay neurons connect sensory and motor neurons.</p> Signup and view all the answers

<p>Cephalopods exhibit advanced cephalization and higher learning abilities compared to other mollusks.</p> Signup and view all the answers

<p>The axon hillock connects the cell body to the axon and integrates incoming signals to determine if an impulse will be sent.</p> Signup and view all the answers

<p>Synapses are the junctions between neurons that allow for the transfer of electrical signals through neurotransmitters.</p> Signup and view all the answers

<p>The mitochondrion is essential for cellular respiration, providing energy required for neuron function.</p> Signup and view all the answers

<p>Receptors in sensory organs detect stimuli and convert them into electrical signals for processing by the nervous system.</p> Signup and view all the answers

<p>EPSPs increase the likelihood of an action potential by depolarizing the membrane, such as by opening Na⁺ channels.</p> Signup and view all the answers

<p>IPSPs decrease the likelihood of an action potential by hyperpolarizing the membrane, for instance, by opening Cl⁻ or K⁺ channels.</p> Signup and view all the answers

<p>A stronger stimulus results in a higher frequency of action potentials, while a weaker stimulus produces fewer action potentials.</p> Signup and view all the answers

<p>A stronger stimulus leads to greater neurotransmitter release in the synapse, enhancing the postsynaptic potential.</p> Signup and view all the answers

<p>The absolute refractory period is when no new action potential can be triggered, while the relative refractory period requires a stronger-than-usual stimulus to generate an action potential.</p> Signup and view all the answers

<p>Neuromodulators like dopamine and hormones like adrenaline can enhance or dampen synaptic activity, influencing ion channel activity and receptor sensitivity.</p> Signup and view all the answers

<p>The all-or-none law states that once the threshold is crossed, an action potential occurs at a consistent magnitude regardless of the strength of the stimulus.</p> Signup and view all the answers

<p>The net effect of excitatory and inhibitory signals determines whether the threshold for an action potential is reached.</p> Signup and view all the answers