Concept explainers
Introduction:
Synapses are the connecting zone or the junctional region between two nerve cells. These regions help in the conduction of the nerve impulses from one neuron to the axon. A synaptic region is generally located between the axon of one neuron and the dendrites of the subsequent one.
Answer to Problem 1DYKB
Correct answer:
The correct answer is option (a) they release neurotransmitters into the synaptic cleft.
Explanation of Solution
Explanation/justification for the correct answer:
Option (a) the axon terminals (of nerve cells) have round knob-like structures called synaptic knobs. These contain secretory vesicles (synaptic vesicles) that release NTs into the synaptic cleft. These NTs are needed for the transmission of nerve impulses from one neuron to another.
Explanation for incorrect answer:
Option (b) The synaptic knobs possess synaptic vesicles. These vesicles transmit the NTs into the subsequent neuron and not back to the synaptic knob. Hence, this is an incorrect option.
Option (c) They conduct graded potentials (action potentials) to the next neuron. Hence, this is an incorrect option.
Option (d) They are located in the axon terminals of a neuron. They conduct nerve impulses to the dendrites of the next one. Hence, this is an incorrect option.
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Chapter 12 Solutions
ANATOMY & PHYSIOLOGY 4/E PAC 2 SEMESTER
- Stellate cells initially process sensory input to the cortex, whereas pyramidal cells send fibers from the cortex to terminate on efferent motor neurons. (True or false)arrow_forwardWhich of these alternatives shows the correct order for a neuron that is leaving the spine? Think of the neuron starting at the spinal cord and an exiting the spine, going to your chest. What would be the path? It would travel out of the spine into the spinal nerve, past the dorsal branch and into the rootlet of the chest. into a spinal nerve, then into a ventral root and then into an anterior branch past a rootlet, into a ventral branch, past a dorsal root, and then to the chest past a rootlet, into a ventral root, into a spinal nerve and then into an anterior brancharrow_forward1) Draw a pseudo-unipolar neuron synapsing onto a dendrite on a multi-polar neuron. Label the cell body on both neurons and the synaptic cleft. 2) Draw a typical neuron and the relative ion concentrations (high or low) for Na+ and K+ inside and outside the cell. 3) If a cation channel suddenly opened at rest which direction would K+ move and why? Which way would Na+ ions move? 2arrow_forward
- Which of the following situations in a neuron results in action potentials that have extended depolarization phases? O None of these result in extended depolarization phase. O Compromising the inactivation mechanism in voltage-gated Na* channels. O Stimulating the voltage-gated K* channels. O Inhibiting the voltage-gated Na* channels. O Compromising the inactivation mechanism in voltage-gated K* channels.arrow_forwardSynaptic transmission depends upon :- a-direct transmission of impulses from the presynaptic neuron to the postsynaptic neuronb- diffusion of neurotransmitters from synaptic knobs into the soma and dendrites of postsynaptic neuronsc- presence of voltage-gated Ca ++ channels in membrane of synaptic knobsd- presence of voltage-gated Ca ++ channels in the subsynaptic membranearrow_forwardWhat terms denotes a sudden change (depolarization and repolarization) in the electrical properties of the neuron membrane? Action potential Synaptic transmission Event-related potential Postsynaptic potential ------------------------------------ You step on a brick, ouch. What type of nerve will bring the signal from your foot to your brain? Somatic afferent Somatic efferent automatic afferent automatic afferent ---------------------------------------------- A given neurotransmitter is inhibitory. What might its receptors do? Allow positive ions to enter the cell Allow negative ions to enter the cell Allow positive ions to leave the cell B and Carrow_forward
- Two separate post-synaptic interneurons receive synaptic potentials from afferent neurons in the periphery. The dendrites of one these interneurons receive an excitatory post-synaptic potential (EPSP) and an inhibitory post-synaptic potential (IPSP) of equal magnitude at the same time. The dendrites of the other interneuron receive one excitatory post-synaptic potential that is the same sized as the EPSP and IPSP received by the other interneuronarrow_forwardWhich statement(s) regarding ions is true when a neuron is at rest? Positively charged cations are attracted to the intracellular fluid Positively charged anions are attracted to the intracellular fluid Negatively charged anions are drawn to the intracellular fluid Negatively charged anions are balanced across the cell membranearrow_forwardWhich of the following would occur if a neuron was experimentally stimulated simultaneously at both ends? The action potentials would pass in the middle and travel to the opposite ends The action potentials would stop as they meet in the middle. The stronger action potential would override the weaker action potential. Summation would occur when the action potentials meet in the middle, resulting in a larger action potential.arrow_forward
- In an experiment, a freshly isolated neuron is placed in a bath that has been almost completely depleted of Na+. After inducing neurotransmitter release with Ca2+ infusion, what would be observed? accumulation of neurotransmitter in the vesicles slow release of neurotransmitter accumulation of the neurotransmitter in the bath no change at allarrow_forwardWhich of the following combinations of spatial summation of postsynaptic potentials (PSP) would result in an action potential in a typical neuron? The voltage given for each PSP is measured as it reaches the axon hillock. Axon A EPSP 25 mV & axon B IPSP 10 mV Axon A IPSP 25 mV & axon B EPSP 10 mV Axon A IPSP 5 mV & axon B IPSP 5 mV Axon A EPSP 5 mV & axon B EPSP 5 mVarrow_forwardExcitatory neurons A and B both synapse with neuron C. Neuron A releasesa neurotransmitter, and neuron B releases the same type and amount ofneurotransmitter plus a neuromodulator that produces EPSPs in neuron C.Action potentials produced in neuron A alone can result in action potentialproduction in neuron C. Action potentials produced in neuron B alone alsocan cause action potential production in neuron C. Which results in moreaction potentials in neuron C, stimulation by only neuron A or stimulationby only neuron B? Explain.arrow_forward
- Human Physiology: From Cells to Systems (MindTap ...BiologyISBN:9781285866932Author:Lauralee SherwoodPublisher:Cengage Learning