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A&P 1 Lecture > A&P 1 Chapter 11 (Lecture) [The Nervous System, Part 2] > Flashcards

A&P 1 Chapter 11 (Lecture) [The Nervous System, Part 2] Flashcards

1
Q

What is the voltage of resting potential?

A

-70mV

Difference in electrical charge between inside and the oi=utside of a cell membrane (voltage)

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2
Q

Na+/K+ Exchange Pump

A

Moves 3 Na+ ions our for every 2 K+ in

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3
Q

Na+ (Direction and Number for Na+/K+ Exchange Pump)

A

Out

3 Na+ ions

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4
Q

K+ (Direction and Number for Na+/K+ Exchange Pump)

A

In

2 K+ ions

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5
Q

Why is it a big deal when Na+ moves across a membrane?

A

It generates electricity

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6
Q

Three Types of Gated (Active) Channels

A
  • Chemically Gated
  • Voltage Gated
  • Mechanically Gated
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7
Q

Chemically Gated Channels

A
  • Open in response to specific chemicals
  • Locations: cell body and dendrites
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8
Q

Voltage Gated Channels

A
  • Open in response to changes in transmembrane potential
    • Have an activation gate and inactivation gate
  • Found in excitable membranes
    • Axons
    • Skeletal Muscle Cells
    • Cardiac Muscle Cells
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9
Q

Mechanically Gated Channels

A
  • Open in response to membrane distortion
  • Locations: sensory receptors
    • Touch, pressure, vibration
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10
Q

Depolarization

A
  • Gated Na+ channels open
  • Na+ enters cell
  • Membrane potential becomes more positive (less negative)
  • Generates Electricity
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11
Q

Hyperpolarization

A
  • Gated K+ channels open
  • K+ exits cell
  • Membrane potential becomes more negative (-80mV)
  • No electric current is made
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12
Q

Graded Potentials (3 Phases)

A
  • Resting
  • Stimulation
  • Depolarization
  • Both Chemically & Mechanically Gated Channels can be involved
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13
Q

GP: Resting Cell

A
  • Transmembrane potential= -70mV
  • Chemically regulated Na+ channels closed
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14
Q

GP: Stimulation

A
  • Membrane exposed to chemical
  • Chemically regulated Na+ channels open
  • Na+ ions begin to enter cell
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15
Q

GP: Depolarization

A
  • Movement of Na+ into cell depolarizes membrane (at stimulation site)
    • Potential moves from -70 mV toward zero (more positive, less negative)
  • Movement of Na+ into cell also produces a local current that depolarizes adjacent membrane segments
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16
Q

Voltage

A

(Potential)

Distance over which electrons can move from positive to negative ends.

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17
Q

Current

A

Number of electrons passing through a point. (Measured in Amps.)

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18
Q

At resting, where is there more Sodium?

A

Outside

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19
Q

At resting, where is there more Potassium?

A

Inside

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20
Q

At resting, where do the the Na+ and K+ ion “want” to be? Why?

A

Na+ wants in, K+ wants out because of the their concentration gradients.

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21
Q

What are the membrane proteins responsible for allowing Na+/K+ in and out of the cell?

A

Gated Channels & The Na+/K+ Pump

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22
Q

Action Potential (Phases)

A
  • Resting
  • Threshold
  • Depolarization/Activation
  • Repolarization/Inactivation
  • Returning to Resting
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23
Q

Resting Phase (Action Potential)

A
  • Transmembrane potential is around -70mV
  • Voltage-gated Na+ channels are closed
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24
Q

Threshold Phase (Action Potential)

A
  • Graded potential (in axon hillock) depolarizes initial segment of axon to threshold (-60mV)
  • Na+ gates begin to open
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25
Q

Depolarization/Activation (Action Potential)

A
  • Voltage-gated Na+ channels open
  • Produces local current
  • Goes to +30mV
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26
Q

Repolarization/Inactivation (Action Potential)

A
  • When the membrane potential reaches about +30mV
  • Voltage-gated Na+ ion channels inactive
  • K+ gates open
  • Na+ gates closed until it reaches -40mV
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27
Q

Return to Resting (Action Potential)

A
  • At -90mV K+ gates close
  • Pump resets the potential back to -70mV
28
Q

Refractory Period

A
  • Period of time during which another action potential cannot be generated.
  • Only applies to action potential
  • 2 Types:
    • Relative
    • Absolute
29
Q

Absolute Refractory Period

A

Membrane cannot respond to another stimulus (Na+ channels are already open or inactivated)

30
Q

Relative Refractory Period

A
  • Membrane potential almost normal
    • Na+ channels in ready state
    • K+ channels are not yet closed
  • Larger than normal stimulus can initiate action potential
    • Membrane is still hyperpolarized (-90mV)
31
Q

What are the differences between graded and action potentials? Are they connected to each other?

A
  • Graded
    • Affect only a small portion of a cell membrane (Allow communication over short distances)
  • Action
    • Affect the entire surface of a cell membrane (Allow communication over long distances)
  • Yes they are connected (Graded CAN produce Action
32
Q

Continuous Propagation

A
  • Unmyelinated Axons
  • Slower
  • Every portion of axon membrane must depolarize
  • Goes by segments
33
Q

Saltatory Propagation

A
  • Myelinated Axons
  • Faster
  • Only axon membrane at nodes of Ranvier must depolarize
34
Q

Why do action potentials only propagate away from the cell body?

A

Because the previous segment hasn’t reset yet.

35
Q

Steps of a Chemical Synapse

A
  1. Action potential arrives and depolarizes synaptic knob.
  2. Synaptic vesicles are exocytosed and neurotransmitter molecules are released. (Ca+ enters synapse)
  3. Neurotransmitter crosses synaptic cleft and binds to receptor.
  4. Ion channels open and graded potential is produced.
  5. Neurotransmitter removed and resting potential membrane is restored.
36
Q

What type of gated channel is present in a synapse?

A

Chemical

37
Q

What is an electrical synapse? How do they work?

A
  • A direct physical connection between cells
  • NS (rare)
    • Eye
    • Some areas of the brain
    • Ciliary ganglia of PNS
  • Action potential always produced in postsynaptic cell
38
Q

What is synaptic fatigue? How does it happen?

A
  • Occurs when neurotransmitter cannot be recycled fast enough to meet demands of intense stimuli
  • Inactive until neurotransmitter is replenished
39
Q

What is synaptic delay? What is the synaptic delay in typical humans.

A

The time it takes from arrival of action potential to the response of the other membrane.

In Humans: 0.2-0.5 milliseconds

40
Q

2 Types of Postsynaptic Potentials

A
  • Excitatory
    • Depolarization
    • Na+ Gated
    • Excitatory Postsynaptic Potential (EPSP)
  • Inhibitory
    • Hyperpolarization
    • K+ Gated
    • Inhibitory Postsynaptic Potential (IPSP)
41
Q

Of the two types of postsynaptic potentials, which can possibly lead to an action potential?

A

Exicitatory

42
Q

2 Types of Summation

A
  • Spatial
    • Multiple connections, all send signals at once
  • Temporal
    • One connection, sends multiple signals
43
Q

Cellular Information Processing

A
  • Involves summation of EPSPs and IPSPs by postsynaptic membrane
  • Influenced by:
    • Temperature
    • Oxygen/nutrients
    • Abnormal chemicals
  • If there is enough neurons set off it will send signal on.
44
Q

Higher Level Information Processing

A
  • Involves regulatory neurons
  • Facilitate or inhibit presynaptic neurons
45
Q

What are regulatory neurons and what can they do?

A

Make presynaptic more or less likely to fire.

Either facilitate (Na+) or Inhibit (K+)

46
Q

ACh

A

Acetylcholine

Used in Cholinergic Synapses

47
Q

Multipolar Neuron

A
  • 2 or more dendrites
  • Single axon
  • Most common CNS neuron
  • PNS motor neurons
  • Transmission
48
Q

Bipolar Neurons

A
  • One dendritic process
    • With extensive distal branching
  • One axon
    • With several telodendria & synaptic terminals
  • Rare; special senses
    • Eyes
    • Nose
    • Ears
49
Q

Unipolar Neuron

A
  • 2nd most common
  • Dendrite continuous with axon
    • Soma off to one side
  • Initial segmentt located where dendrites fuse
  • PNS sensory neurons
50
Q

Anaxonic Neuron

A
  • Cannot differentiate between axons and dendrites
  • Brain, special sense neurons
  • Function not yet understood
51
Q

Somatic Neurons (Sensory Neurons)

A

Recieves info from external environment

52
Q

Visceral Neurons (Sensory Neurons)

A

Monitors Organs

53
Q

Sensory Neurons

A
  • Somatic
  • Visceral
54
Q

Motor Neurons

A
  • Somatic
  • Visceral
55
Q

Somatic Neurons (Motor Neurons)

A

Cover skeletal

56
Q

Visceral Neurons (Motor Neurons)

A

Smooth Muscle & Cardiac Muscle

57
Q

Inter Neurons

A

Connects sensory neurons to motor neurons

58
Q

Neuroglia of CNS

A
  • Microlgia
  • Astrocytes
  • Oligodendrocytes
  • Ependymal Cell
59
Q

Astrocytes

A

Anchor blood vessels (Maintain Homeostasis)

60
Q

Oligodendrocytes

A

Myelin Sheath

61
Q

Microglia

A

Security & Janitor

62
Q

Ependymal Cell

A

Produce CSF (Ciliated)

63
Q

Neuroglia of PNS

A
  • Schwann Cells
  • Satellite Cells
64
Q

Schwann Cells

A

Myelin Sheath

65
Q

Satellite Cells

A

Act like Astrocytes (Homeostasis)

A&P 1 Lecture (9 decks)

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