Concept explainers
To discuss:
The mechanism of action potential; and how it is related to the flow of ion and the membrane channel action; what is the meaning of repolarization and depolarization in the membrane during the action and local potential.
Introduction:
An action potential is electrical impulses used for information passage between the nerve cell and muscle cell. The postsynaptic neuron is a neuron in which electrical impulses are transmitted by the chemical neurotransmitter release. Any alterations in the membrane potential are postsynaptic potential. Its function is to inhibit or initiate an action potential that is aided by neurotransmitters.
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Chapter 12 Solutions
LSC (CONCORDIA UNIV ST PAUL) BIO 315/316: B&N DPF Connect with APR and Phils Online Access for Anatomy and Physiology: The Unity of Form and Function 180 Day Access ENTRP
- Neuromuscular junction, also called myoneural junction, site of chemical communication between a nerve fibre and a muscle cell. The neuromuscular junction is analogous to the synapse between two neurons. A nerve fibre divides into many terminal branches; each terminal ends on a region of muscle fibre called the end plate. Synaptic Cleft is the space between the presynaptic terminal and postsynaptic cell. It is roughly the size of 30 nm. The synaptic cleft allows the neurotransmitters to diffuse and reach the other side of the synapse or the neuromuscular junction. It also contains enzymes for the degradation of the excess or extra neurotransmitters. Embedded in the end plate are thousands of receptors, which are long protein molecules that form channels through the membrane. Upon stimulation by a nerve impulse, the terminal releases the chemical neurotransmitter acetylcholine from synaptic vesicles. Acetylcholine then binds to the receptors, the channels open, and sodium ions flow into…arrow_forwardSteps that occur in a neuron Defore, during, and affer action Potentialarrow_forwardHow stimulation of a neuron generates a local potential; the physiological properties of a local potential.arrow_forward
- When the membrane voltage shifts from the RMP to a more negative voltage; this is a depolarization repolarization hyperpolarization polarizationarrow_forwardElectrophysiology of the Neuron Phase State of lon Channels Movement of lons Voltage Across Membrane RMP Resting Membrane Potential Hyperpolarizing Graded Potential IPSP Depolarizing Graded Potential EPSP Depolarization Phase of Action Potential Peak of Action Potential Repolarization Phase of Action Potential Hyperpolarization Phase of Action Potential Return to RMP All voltage gated channels - CLOSED All chemically gated channels -CLOSED Voltage gated Na* CLOSED Voltage gated Na' OPEN Na+ and K+ leak channels - OPEN Na+ K+ pump working K+ Voltage gates close slowly Voltage gated K* CLOSED Voltage gated K* OPEN Cl- chemically gated channels- OPEN Na+ chemically gated channels-OPEN K+ chemically gated channels -OPEN 2 K+ pumped IN 3 Na+ pumped OUT K+ diffuses OUT Na* diffuses IN K+ diffuses out or Ch -70 mV to -56 mV -55mV to +30 mv -70 mV +30mv More negative than -70 mV +30mV to -70 mVarrow_forwardNerve transmission and communication with other neurons. DI it restores the membrane potential the chemical that talks between one neuron and the other neuron the point between the neuron and the muscle transmits impulse to dendrite it carries receptors on its surface it produces the neurotransmitter 1. Neurotransmitter 2. Presynaptic membrane 3. Postsynaptic membrane 4. Nat-K+ pump 5. Neuromuscular junction 6. Axonarrow_forward
- An influx of positive sodium ions eventually causes closing of the inactivation gates of voltage regulated sodium channels, stopping the influx of positive sodium ions, and thus the final stages of an action potential are regulated by _____ feedback.arrow_forwardsummary of the whole process of action potentialarrow_forwardThe membrane voltage in graded potentials can be produced by Oopen channels and ligand-gated chanels Ovoltage-gated channels Oligand-gated and mechanically gated channels Oligand-gated channels mechanically gated channelsarrow_forward
- Which characteristic does not refer to electrical potentials? involve gap junctions are slower by very few milliseconds include graded potentials produce synchronous action potentials in pre- and post-synaptic membranesarrow_forwardWhy the membrane potential is not equal to the equilibrium potential?arrow_forwardThe resting voltage of the cell membrane: O is a property of the cell O is generated by mechanically-gated channels, voltage-gated channels, and ligand-gated channels O is defined by the difference in overall ionic charges between the two sides of the membrane O has a negative value at rest in all cells except neurons O all of the abovearrow_forward
- Human Physiology: From Cells to Systems (MindTap ...BiologyISBN:9781285866932Author:Lauralee SherwoodPublisher:Cengage Learning
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