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CMSD5290 Intro to Neuroscience > Activity of Neurons > Flashcards

Flashcards in Activity of Neurons Deck (58)
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1
Q

Information conducting unit of the nervous system

A

Neuron

2
Q

What are the functions of dendrites? (2)

A
  • Collect information from other cells
  • Increase cell’s surface area
3
Q

What are Dendritic spine?

A

Small protrusions that cover the dendrites

4
Q

Describe the axon of a neuron. (4)

A
  • Extends out from the cell body
  • Axon hillock
  • Axon collateral - branches of the axon
  • Teleodendria - smaller branches toward the end
5
Q

What are terminal boutons? Where do they sit?

A
  • End foot’ at the end of each teleodendrion
  • Sits close to the dendritic spine of another neuron
6
Q

What is a synapse?

A

Space between the terminal button of one neuron and dendritic spine of another

7
Q

What is a Neurotransmitter?

A

Chemical released from terminal buttons that carries the message across the synapse

8
Q

Dopamine is an _____________ neurotransmitter.

A

inhibitory

9
Q

What encapsulate the neurotransmitters in the terminal boutons?

A

Vesicles

10
Q

What does the nucleus of a neuron contain?

A

Chromosomes and genes

11
Q

What is intracellular fluid of a neuron?

A

Fluid in which the cell’s internal structures are suspended

12
Q

What is the cell membrane in neurons?

A

membrane surrounding the cell

13
Q

Extracellular fluid, fluid outside , c__________ the cell

A

cushions

14
Q

What is another name for intracellular fluid?

A

Cytoplasm (Salty Water)

15
Q

True or False:
Concentration of dissolved substances in extracellular and intracellular fluid is THE SAME

A

False Concentration of dissolved substances in extracellular and intracellular fluid is DIFFERENT, this difference is very important for allowing a neuron to conduct electrical signal

16
Q

The cell membrane is impermeable, what does impermeable mean?

A

Does not allow liquid to pass (hydrophobic)

17
Q

How do substances like potassium and sodium cross the neuron cell membrane?

A

From extracellular fluid, the substances cross the membrane via embedded proteins (channels, gates or pumps)

18
Q

What are the five steps of a Nerve impulse?

A
  • Resting potential
  • Action potential (Depolarization Phase)
  • Repolarization
  • Hyperpolarization
  • Restoration of Potential
19
Q

Which step describe this nerve impulse step:
Cell membrane is polarized (i.e., electrical difference between inside & outside of cell)
Intracellular fluid has a negative charge relative to the extracellular fluid
Difference in charge is about -70mV
Maintained by efflux (i.e., exit) of Na+ and influx (i.e, entry) of K+
Sodium-Potassium pump works continuously exchanging 3 Na+ for 2 K+
Since more Na+ exits than K+ enters, intracellular fluid is negatively charged

A

The Resting potential

20
Q

Which step describe this nerve impulse step: Na+ channels close
Voltage-sensitive K+ channels open causing rapid efflux of K+
Intracellular fluid develops a more negative charge relative to the extracellular fluid

A

Repolarization

21
Q

Which step describe this nerve impulse step: K+ efflux overshoots
Causes brief period in which charge of intracellular fluid relative to extracellular fluid is even more negative than in resting state

A

Hyperpolarization

22
Q

Which step describe this nerve impulse step: Cell membrane receptors activated by external or internal stimuli
If -50 mV threshold reached, there is a brief but extremely large flip in the polarity of cell membrane
Voltage-sensitive Na+ channels open causing rapid influx of Na+
Intracellular fluid develops a positive charge relative to the extracellular fluid

A

Depolarization

23
Q

Which step describe this nerve impulse step: Sodium-Potassium pump reactivated (3 Na+ out for 2 K+ in)
Cell membrane polarized (-70 mV)

A

Restoration of Resting Potential

24
Q

What are the two types of Refractory Period?

A

Absolute Refractory Period
Relatively Refractory Period

25
Q

What is the difference between the absolute and relatively refractory periods?

A

Absolute refractory period: the period of time during which no amount of external stimulus will generate an action potential. Relative refractory: period of time during which only a large stimulus will generate an action potential.

26
Q

What are refractory periods?

A

Time period during which neuron cannot fire again unless a large amount of stimulus can make the neuron fire again

27
Q

Why are refractory periods important in the nerve impulse process?

A
  • Limits action potential frequency & prevents backward flow of signal
  • Typical rate = 30 action potentials/sec
28
Q

What is saltatory conduction?

A

the way an electrical impulse skips from node to node of Ranvier down the full length of an axon

29
Q

Why did we develop myelin sheath for axons relating to skull size?

A

Because our skull size limits how big and how many neurons will fit, so it speeds up signal transmission

30
Q

Large Axon = _____ transmission of the action potential
** size refers to diameter, not length

A

Quick

31
Q

Axon =______
transmission of the action potential
** size refers to diameter, not length

A

Slow

32
Q

What structure is this?
Uninsulated regions between the myelinated segments
Action potentials can only be propagated here (since myelin creates a barrier to flow of ions & therefore electrical change)

A

Nodes of Ranvier

33
Q

Saltatory Conduction greatly ________ the rate of transmission of the action potential.

A

Increases

34
Q

Describe what occurs when there is an action potential reaches axon terminal.

A
  • causes a chemical to be released into synaptic gap
  • A neurotransmitter is a chemical (or occasionally a gas) that is released at a synapse to transmit signals to a postsynaptic neuron (or muscle)
35
Q

(2) It is
– Located inside the axon terminal
– Contain the neurotransmitter

A

Synaptic Vesicles and Storage Granules

36
Q

Membrane on the dendritic spine

A

Postsynaptic Membrane

37
Q

Space between the axon terminal and the dendritic
spine

A

Synaptic Cleft

38
Q

Membrane on the axon termina

A

Presynaptic Membrane

39
Q

What are the steps in synaptic transmission?

A

• Wave of depolarization to axon terminal
• Vesicles migrate presynaptic mem.
• Exocytosis
• Neurotransmitter binds to receptor
• Response is generated in
postsynaptic structure
• Type of response depends on
neurotransmitter (NT)

40
Q

Neurotransmitter released into
synaptic cleft: what is this process?

A

Exocytosis

41
Q

What is a neuromuscular junction in the PNS?

A

Axon to muscle synapse

42
Q

True or False: A neurotransmitter typically has one
type of receptors that it can bind to

A

FALSE: A neurotransmitter typically has MULTIPLE
types of receptors that it can bind to

43
Q

True or False: MANY neurotransmitters are associated with a single type of influence

A

FALSE: No one neurotransmitter is associated with
a single type of influence

44
Q

What is the link between excitatory neurotransmitters and depolarization?

A

Excitatory neurotransmitters depolarize
the post-synaptic membrane (increasing
likelihood of AP)

45
Q

What is the link between inhibitory neurotransmitters and hyperpolarization ?

A

Inhibitory neurotransmitters hyperpolarize the post-synaptic membrane (decreasing
likelihood of AP)

46
Q

What is summation?

A

Process by which postsynaptic neuron “adds up” all of the excitatory & inhibitory inputs

47
Q

What are the two types of summation?

A

Temporal and spatial summation

48
Q

Explain what occurs during SPATIAL summation. Draw it

A
  1. Simultaneous stimulation by several presynaptic neurons
  2. Excitatory Post Synaptic Potentials (EPSPs) spread from several synapses to axon hillock
  3. PS neuron Fires
49
Q

Explain what occurs during TEMPORAL summation. Draw it.

A
  1. High Frequency stimulation by one presynaptic neuron
  2. Excitatory Post Synaptic Potentials (EPSPs) spread from one synapses to axon hillock
  3. PS neuron Fires
50
Q

What is EPSP-IPSP cancellation? Draw it

A

When Inhibitory input cancel out depolarization of Excitatory input through hyperpolarization.

51
Q

Describe Acetylcholine NT (3)

A
  • Muscle activation in PNS
  • Sleep/wakefulness & memory in CNS
  • Depletion = Alzheimer’s
    disease
52
Q

NT Involved in sympathetic NS:

A

Epinephrine `

53
Q

NT Involved in arousal & attention:

A

Norepinephrine

54
Q

NT Involved in movement & pleasure/reward and Depletion associated with Parkinson’s
disease

A

Dopamine

55
Q

NT Involved in mood, aggression, appetite,
arousal, pain, respiration.

A

Serotonin (5-HT)

56
Q

Describe what Major Activating Systems are? (3)

A

• Cell bodies gathered into nuclei in brainstem
• Axons project throughout brain and
synapse on target structures
• Each activating system is associated with different behaviors and diseases

57
Q

What occurs in the axon hillock?

A

sums up the total signals received, both inhibitory and excitatory signals. If this sum exceeds the limiting threshold, the action potential is triggered

58
Q

Explain MS. (4)

A
  • Degenerative disease
  • Attacks the myelin CNS
  • Disrupts flow of signals
  • Symptoms auditory, visual, somatosensory, motor & cognitive disturbances, fatigue