A&P 2.15 Action Potential or Nerve Impulse Flashcards

0
Q

Iliopsoas

A, I, O

A

A - hip flexion, major postural muscle

I - iliacus muscle and lesser trochanter

O - vertebral bodies, anterior discs of T12-L5 and TP of L1-L5, iliac fossa

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1
Q

Iliopsoas

A

Two muscles

Iliacus And psoas major

Strongest hip flexor

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2
Q

Iliacus

A, I, O

A

A - origin fixed: flex the hip
Insertion fixed: flex the trunk toward the thigh

I - lesser trochanter

O - iliac fossa

Named for location: ilium, loin

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3
Q

Psoas major

A, I, O

A

A - origin fixed: flex the hip
Insertion fixed: flex trunk toward the thigh
Unilaterally- assist to laterally flex the lumbar spine

O - bodies of the transverse process of lumbar vertebrae

I - lesser trochanter

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4
Q

Ribs are what to the transverse processes they attach to

A

Anterior

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5
Q

Lesser trochanter

A

Posterior medial

Inferior to the greater trochanter

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7
Q

Ions

A

Electrically charged atoms or molecules

Positive or negatively charged

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8
Q

Ions

Three states

A

Neutral atoms - equal number of protons and electrons
Negative ions - have more electrons
Positive ions - have fewer electrons

Number of protons do not change

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9
Q

Most plentiful outside cell ions

A

NA+ sodium

CL- chlorine

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10
Q

Most plentiful ion intercellular

A

K+ potassium

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11
Q

Membrane potential

A

A difference in electrical charge across the plasma membrane caused by differing concentration of ions across a membrane

Called a potential because it is a type of stored energy called potential energy

Every cell in the body maintains a membrane potential

A membrane that exhibits a membrane potential is said to be polarized

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12
Q

Resting membrane potential

A

When a neuron is not conducting electrical signals is said to be “resting”

-70 mV

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13
Q

What can generate action potentials?

A

Only muscle cells and neurons can generate an action potential

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14
Q

Action potential

A

An impulse results when ions are allowed to move toward each other

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15
Q

Sodium-potassium pump

A

The mechanism in the plasma membrane actively pumps sodium ions (Na+) out of the neuron (cell) and potassium ions (K+) into the neuron at an unequal rate (3:2)

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16
Q

Local potentials

A

In neurons, membrane potentials can fluctuate above or below the resting membrane potential in response to certain stimuli

A slight shift away from resting membrane potential in a specific region of the plasma membrane is often called a local potential

17
Q

Excitation

A

When any stimulus causes gates or channels to open and causes the RMP to reach -59 MV

Called depolarization

18
Q

Inhibition

A

Movement of the membrane potential away from zero below usual RMP called hyperpolarization

19
Q

Action potential

A

The membrane potential of an active neuron while conducting an impulse

20
Q

Action potential

A

Same as spreading wave

21
Q

Refractory period

A

A brief period during which a local area of an axon’s membrane resists re-stimulation for about 1/2 millisecond after then membrane surpasses the threshold potential, IT WILL NOT RESPOND TO ANY STIMULUS NO MATTER HOW STRONG (absolute) or VERY STRONG (relative)

21
Q

How do anesthetics affect pain?

A

Block ability of nerve potential to continue by binding to the postsynaptic nerve receptors

22
Q

Action potential process

6 Steps

A
Stimulus
Threshold potential reached
Action potential peaks
Repolarization
Hyperpolarization 
Resting potential restored
23
Q

Stimulus

A

Anything that changes the resting membranes potential (-70 Mv)
Triggers stimulus gated Na+ channels to open
Allows Na+ inward diffusion

MEMBRANE DEPOLARIZES (Decreases from -70 Mv toward -59 Mv)

24
Q

Threshold potential reached

A

Membrane reaches -59 Mv

Voltage gated Na+ channels open

25
Q

Action potential peaks

A

More Na+ enters cell
Depolarization continues until +30 Mv
ACTION POTENTIAL PEAKS AT +30 Mv
Voltage gated Na+ channels close

26
Q

Repolarization

A

Moving back toward resting membrane potential (-70 Mv)
Begins when voltage gated K+ channels open
Allows outward diffusion of K+

27
Q

Hyperpolarization

A

K+ exits cell and moves toward resting membrane potential (-70 Mv)
Membrane potential increases beyond resting membrane potential to -100 Mv
HYPERPOLARIZATION ABOVE -70 Mv

28
Q

Resting potential restored

A

Sodium-potassium pump activates to restore resting membrane potential (-70 Mv)
Decreases membrane potential from -100 Mv (hyperpolarization) to normal (-70 Mv)
Ion channels return to resting state

29
Q

All or none phenomenon

A

Each action potential is all or nothing

If the threshold (-59 Mv) is surpassed, the full peak action potential is always reached

If threshold potential is not surpassed, no action potential will occur at all

30
Q

How does myelin affect conduction of the action potential

A

Myelinated greatly increases the speed due to nodes of Ranviea