nerve impulse

Examples of nerve impulse in the following topics:

• The Ear

  • The ear is the sensory organ that picks up sound waves from the air and turns them into nerve impulses that can be sent to the brain.
  • The ear is the sensory organ that picks up sound waves from the surrounding air and turns them into nerve impulses, which are then sent to the brain.
  • In this way sound waves are transformed into nerve impulses.
  • The nerve impulses travel from the left and right ears through the eighth cranial nerve to both sides of the brain stem and up to the part of the cerebral cortex dedicated to sound (auditory cortex, located in the temporal lobe).
  • Describe how sound waves are collected and transformed into nerve impulses

• Electric Potential in Human

  • In humans, they are seen in cell membranes and nerve impulses in particular.
  • When the brain decides on an action, it sends an impulse that cascades to the extremity where a muscle contracts.
  • Neurons receive an impulse at the dendrites.
  • Neurons receive an impulse at the dendrites.
  • This impulse is passed through the axon, a long extension of the cell, in the form of an electrical potential created by differing concentrations of sodium and potassium ions on either side of a membrane in the axon.

• Nerve Conduction and Electrocardiograms

  • There are three major functions of nerves.
  • Nerve conduction is a general term for electrical signals carried by nerve cells.
  • How does it get transmitted along the cell membrane as a nerve impulse?
  • Thus the action potential stimulated at one location triggers a nerve impulse that moves slowly (about 1 m/s) along the cell membrane.
  • Just as nerve impulses are transmitted by depolarization and repolarization of an adjacent membrane, the depolarization that causes muscle contraction can also stimulate adjacent muscle cells to depolarize (fire) and contract.

• Humans: Work, Energy, and Power

  • (Nerve cells use this electrical potential in nerve impulses. ) This bioelectrical energy ultimately becomes mostly thermal energy, but some is utilized to power chemical processes such as in the kidneys and liver, and in fat production.

• Human Perception of Sound

  • The sound waves are then transmitted from the elliptical window through the inner ear's semicircular canals, the cochlea, and the audio nerve, which is filled with fluid.
  • These vibrations release electrical impulses to the auditory nerve and are then sent to your brain, where they are understood as sound.

• Electric Activity in the Heart

  • The electric energy that stimulates the heart occurs in the sinoatrial node, which produces a definite potential and then discharges, sending an impulse across the atria.
  • In the atria the electrical signal moves from cell to cell (see section on nerve conduction and the electrocardiogram) while in the ventricles the signal is carried by specialized tissue called the Purkinje fibers which then transmit the electric charge to the myocardium. shows the isolated heart conduction system.
  • The sinoatrial node (also commonly spelled sinuatrial node) is the impulse-generating (pacemaker) tissue located in the right atrium of the heart: i.e., generator of normal sinus rhythm.
  • Although all of the heart's cells have the ability to generate the electrical impulses (or action potentials) that trigger cardiac contraction, the sinoatrial node normally initiates it, simply because it generates impulses slightly faster than the other areas with pacemaker potential .
  • High magnification micrograph of sinoatrial node tissue and an adjacent nerve fiber.

• Impulse

  • Impulse, or change in momentum, equals the average net external force multiplied by the time this force acts.
  • The quantity of impulse is force × time interval, or in shorthand notation:
  • Therefore, impulse as defined in the previous paragraph is simply equivalent to p.
  • Thus, the impulses and their effects are the same for both the actual and effective forces.
  • A brief overview of momentum and impulse for high school physics students.

• Linear Systems

  • The result of impulsively exciting a system, such as striking a bell with a hammer, is called the impulse response.
  • The way to represent an impulsive function mathematically is with a Dirac delta.
  • You can probably think of lots of examples of impulse response measurements.
  • So $g$ is the response of our system to an impulsive force: this is why it is known as the impulse response.
  • Now suppose we convolve the force $f$ with the impulse response.

• Orbital Maneuvers

  • ve is the effective exhaust velocity (ve=Isp • g0 where Isp is the specific impulse expressed as a time period and g0 is the gravitational constant); and
  • Oberth effect is used in a powered flyby or Oberth maneuver in which the application of an impulse (typically from the use of a rocket engine) close to a gravitational body (where the gravity potential is low and the speed is high) allows for more change in kinetic energy and final speed (i.e. higher specific energy) than the same impulse applied further from the body for the same initial orbit.
  • The orbital maneuver to perform the Hohmann transfer uses two engine impulses that move aspacecraft onto and off the transfer orbit, as diagramed in .

• Rocket Propulsion, Changing Mass, and Momentum

  • The momentum of the entire system (rocket plus expelled gas) has actually decreased because the force of gravity has acted for a time Δt, producing a negative impulse Δp=−mgΔt.
  • (Remember that impulse is the net external force on a system multiplied by the time it acts, and it equals the change in momentum of the system. ) So the center of mass of the system is in free fall but, by rapidly expelling mass, part of the system can accelerate upward.
  • By calculating the change in momentum for the entire system over Δt, and equating this change to the impulse, the following expression can be shown to be a good approximation for the acceleration of the rocket.