Nervous System Overview and Action Potentials 1 Flashcards

1
Q

What are the overall functions of the nervous system

A

keep the body in systemic homeostatic processes by
-muscle contraction
-integration of blood oxygen, carbon dioxide, and pH levels via respiratory activity
-regulation of volumes and pressures in circulation via cardiovascular and urinary function
-digestive system motility and secretion

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2
Q

What is the functional unit of nervous system?

A

neurons

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3
Q

What are neuroglia?

A

support cells for neurons

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4
Q

What type of signals does the nervous system use?

A

both electrical and chemical signals

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5
Q

What is the integrating center of the nervous system?

A

the CNS
-brain and spinal cord

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6
Q

What cells are a part of the effector pathway in the nervous system?

A

motor neurons

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7
Q

What cells are a part of the affector pathway in the nervous system?

A

sensory neurons

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8
Q

What are dendrites?

A

ends of the neurons that are stimulated by environmental changes or the activities of other cells

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9
Q

What are the cell body of neurons?

A

parts of the neurons that contain the nucleus and organelles

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10
Q

What is the axon hillock?

A

the first part of the axon

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11
Q

What is the axon?

A

the part of the neuron that conducts the nerve impulses

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12
Q

What are the synaptic terminals?

A

ends of the neuron that affect other neuron or effector organ

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13
Q

What are the nissl bodies?

A

clusters of ribosomes in the nucleus that give a gray appearance

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14
Q

Where are there more nissl bodies?

A

in the gray matter of the brain

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15
Q

What are internodes?

A

the segments of the myelin on a neuron

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16
Q

What make the internodes in the PNS?

A

Schwann cells

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17
Q

What make the internodes in the CNS?

A

Oligodentrocytes

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18
Q

What is the space that separates the internodes on the axon of a neuron?

A

nodes of Ranvier

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19
Q

What is the function of the neurons?

A

speed up the rate of the nerve impulse

20
Q

What is saltatory conduction?

A

the jumping of action potential down the axon with the use of the myelin

21
Q

What are sensory neurons?

A

-parts of the afferent division of PNS
-carry sensory info from reflex to CNS
-axons typically myelinated and extend to CNS
-dendrites/cell bodies in PNS

22
Q

What type of neurons are sensory neurons usually?

A

pseudounipolar or bipolar

23
Q

What are motor neurons?

A

-efferent division of PNS
-carry motor commands from CNS to effectors
-dendrites/cell bodies in CNS
-ions typically myelinated, extend into PNS and synapse with effectors

24
Q

What type of neurons are motor neurons usually?

A

multipolar

25
Q

What are interneurons?

A

-found only in CNS
-carry information from one neuron to another
-integration
-may or may not be myelinated

26
Q

What type of neurons are interneurons?

A

multipolar or anaxonic

27
Q

What are the two types of electrical signals in neurons?

A

action potentials and graded potentials

28
Q

What are action potentials?

A

-always the same with no change in strength or size as they travel
-all-or-none
-triggered at axon hillock when threshold potential reached
-always propagates along cell membrane
-relatively fast changes in Vm

29
Q

What are graded potentials?

A

-small changes in membrane potential of variable strength/amplitude
-only travel a short distance along membrane and lose strength as they travel
-typically last longer than APs

30
Q

What are synaptic potentials?

A

generative in post synaptic cell in a synapse

31
Q

What are EPSPs?

A

excitatory postsynaptic potentials
-depolarizations
-Vm move toward threshold potentials
-increase likelihood of AP

32
Q

What are IPSPs?

A

inhibitory postsynaptic potentials
-hyperpolarizatios
-move away from Vm
-decrease likelihood of Vm

33
Q

What are receptor potentials?

A

reflex receptor
-excitatory

34
Q

What are end plate potentials?

A

skeletal muscles
-excitatory

35
Q

What is depolarization?

A

Vm becomes more positive
-EPSPs

36
Q

What is repolarization?

A

Vm returns to resting value

37
Q

What is hyperpolarization?

A

Vm becomes more negative than resting
-IPSPs

38
Q

What happens to Na channels when the membrane potential reaches threshold?

A

voltage gated sodium channels open and allow Na to enter the cell rapidly

39
Q

Once the action potential gets to the amplitude, what happens to the Na and K channels?

A

the voltage gated Na channels close and the voltage gated K channels open and K flows out

40
Q

What causes hyperpolarization?

A

the voltage gated K channels remain open after resting membrane potential is reached, so more K can leave causing the membrane potential to become more negative than rest

41
Q

What is special about the voltage gated Na channels?

A

there are two gates
-activation gate
-inactivation gate

42
Q

How does the activation gate of voltage gated Na channels work?

A

closed at resting membrane potential
-quickly open at threshold depolarization

43
Q

How does the inactivation gate of voltage gated Na channels work?

A

open at resting membrane potential
-slowly closes at threshold depolarizataion

44
Q

How do voltage gated K channels work?

A

single voltage gate begins to open at threshold
-but is slow
-open around the same time the VG channel inactivation gate closes

45
Q

Does Na or K have a faster conductance through voltage gated channels?

A

Na
-the activation gate is fast and opens quickly allowing Na to flow faster than K

46
Q

What type of feedback does activation of Na channels occur?

A

positive feedback