Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BIO 202 Alara > Lecture 7: Electrical Signalling > Flashcards

Lecture 7: Electrical Signalling Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

Who are the first people to suggest that neurons work like circuits?

A

Hodgin and Huxley

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What did Hodgin and Huxley study?

A

They studied a squid because it has one of the longest neurons.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the most basic unit of the nervous system?

A

The neuron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are neurons able to do?

A
  1. Nerves carry signals from our sensory organs and others to the Central Nervous System (CNS)
  2. Nerves carry signals from the CNS to muscles and other organs
  3. Nerves transmit and process signals within the central nervous system
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Anatomy of a Neuron and its parts

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Define Dendrite

A

Dendrites are projections from the cell body, or soma, of neurons, the cells of the nervous system.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Dendrite function?

A

Receive electrical signals from other neurons, called pre-synaptic neurons, in the form of neurotransmitters.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Cell Body (Soma) function?

A

The cell body is the core section of the neuron.

The cell body contains genetic information, maintains the neuron’s structure, and provides energy to drive activities. Like other cell bodies, a neuron’s soma contains a nucleus and specialized organelles.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is an axon and what is its function?

A

This is portion of a nerve cell (neuron) that carries nerve impulses away from the cell body.

Signals travel through this from the cell body to terminals - transmits electrical signals to neurons, muscles, glands.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is a Myelin Sheath?

A

The myelin sheath is a protective membrane that wraps around part of certain nerve cells.

Speeds up nerve impulse transmission.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are Myelins made of?

A

Fats and proteins - so they are excellent insulators!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is a Node of Ranvier?

A

Nodes of Ranvier are gaps in the myelin sheath coating on the neural axon. The myelin allows the electrical impulse to move quickly down the axon. The nodes of Ranvier allow for ions to diffuse in and out of the neuron, propagating the electrical signal down the axon. In other words, their function is to speed up propagation of action potentials along the axon via saltatory conduction. As the electrical signal or impulse travels along the axon, it jumps from one node to the next.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Internode

A

Each section of myelin is called an internode.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is each gap in the myelin sheath called?

A

Nodes of Ranvier

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is an axon terminal?

A

Axon terminals are the ends of axons which transmit messages to other cells via use of neurotransmitters at synapses.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the function of an axon terminal?

A

Functionally, the axon terminal converts an electrical signal into a chemical signal. When an action potential arrives at an axon terminal (A), the neurotransmitter is released and diffuses across the synaptic cleft.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is neurogenesis?

A

Birth of new neurons, continues into adulthood.

New neurons play an important role in learning.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Name the four types of Neuroglial Cells in the CNS

A
  1. Ependymal cells
  2. Microglial cells
  3. Astrocytes
  4. Oligodendrocytes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Neurons vs Neuroglial Cells

A

The nervous system consists of neurons and glial cells. Neurons generate and propagate electrical and chemical signals, whereas glia function mainly to modulate neuron function and signaling.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the function of Ependymal Cells?

A

A glial cell in the CNS. Ependymal cells are important cells that line the fluid-filled spaces in the brain and acts as a key barrier between the cerebrospinal fluid and the underlying brain tissue.

Their primary function is to regulate what flows in and out of the brain to maintain overall brain health.

Assists in producing, circulating and monitoring cerebrospinal fluid (CSF)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Name the two types of Neuroglial Cells in the Peripheral Nervous System

A
  1. Schwann Cells
  2. Satellite Cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

True or False: Ependymal cells are connected to the cell body

A

False, they are connected to the dendrites

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the function of Microglial Cells

A

A glial cell in the CNS. Mobile phagocytic cells that remove celullar debris, waste products and pathogens.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

True or False: Glial cells send signals

A

False, glial cells do not send signals but helps support and maintaining neurons and CSF health

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the function of Astrocytes?

A

-Glial cell in the CNS
-Maintains the blood-brain barrier by keeping away the blood from interacting with neurons (isolates the CNS)
-Structural support
-Regulate ion, nutrient and gas concentration in interstitial fluid around neurons
-Absorb/recycle neurotransmitters
-Form scar tissue after injuries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is the function of Oligodendrocytes?

A

-Glial cell in the CNS
-Responsible for stabilizing the axon
-Produce myelin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is the function of Schwann Cells?

A

-Glial cells in the PNS
-Participate in axon repair
-Wraps the axon and produces myelin for the myelin sheath production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is the equivalent of Schwann Cells (PNS) in the CNS?

A

Oligodendroctyes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is the function of Satellite Cells?

A

Regulate environment around neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is the equivalent of Satellite Cells (PNS) in the CNS?

A

Astrocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Anaxonic Neuron

A
  • Doesn’t have any dendrites or projections
    -Mostly found in the CNS
    -Doesn’t need to send signals far, that’s why it doesn’t have projections
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Unipolar Neuron

A

-Has one extension from the cell body
- Insects have this, but we humans don’t have these neurons
- The cell body acts as the dendrite, and there is a terminal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Bipolar Neuron

A
  • Two projections
  • Information is received one way and passed down another way
34
Q

Multipolar Neuron

A
  • a most common type of neuron
  • Has more than two dendrites
  • Has one axon
  • Therefore it can receive information from multiple things but only deliver through one
    axon
  • Big neurons, such as motor neurons
35
Q

Pseudounipolar Neuron

A

has a dendrite on one end and a terminal on the other

36
Q

What is Equilibrium Potential

A

-The cell has a hydrophobic membrane
- The membrane is impermeable to charged ions
- Has channels that are permeable to certain ions

37
Q

Neuroglial Cells in the CNS Anatomy

A
38
Q

Inside the cell

A

-Negatively charged proteins
-Mostly K+ and less Na+

39
Q

Potassium (K+) has a tendency to _____ cells

A

LEAVE

40
Q

Sodium (Na+) has a tendency to ______ cells

A

ENTER

41
Q

Outside the cell

A

Mostly Na+ and less K+

42
Q

On the membrane

A

Leaky channels (more K+ leaky channels than Na+ leaky channels)
Na-K pump

43
Q

Voltage inside of the membrane at rest is

A

-70 mV

44
Q

Define membrane potential

A

The difference in total charge between the inside and outside of the cell is called the membrane potential

45
Q

Depolarization

A

Membrane potential becomes more positive (interior is more positive)

46
Q

Hyperpolarization

A

Membrane potential becomes more negative (interior is more negative)

47
Q

Repolarization

A

Membrane voltage returns to resting state - can go either positive or negative

48
Q

Define Graded Potential

A

Graded potentials are changes in membrane potential that vary according to the size of the stimulus, as opposed to being all-or-none.

49
Q

True or False: Change in membrane potential is proportional to the stimulus applied

A

True

Less Neurotransmitters - less ion channels open - smaller magnitude of graded potential

More Neurotransmitters - more ion channels open - larger magnitude of a graded potential

50
Q

Define Axon Hillock

A

The axon hillock is the region of a neuron that controls the initiation of an electrical impulse based on the inputs from other neurons or the environment.

51
Q

What does the net change in postsynaptic membrane voltage determine?

A

Net change in the postsynaptic membrane voltage determines whether the postsynaptic cell has reached the threshold required for an action potential

52
Q

What is synaptic summation?

A

A single neuron can receive both excitatory and inhibitory inputs from multiple neurons. All these inputs are added together at the axon hillock. If the EPSPs are strong enough to overcome the IPSPs and reach the threshold of excitation, the neuron will fire.

53
Q

Why is synaptic summation and threshold important?

A

Act as a filter so that random “noise” in the system is not transmitted as important information

54
Q

Integration of information

A

-Single neuron may receive information from thousands of synapses
-Axon hillock integrates all stimuli, determines rate of action potential generation at initial segment

55
Q

Where is an action potential generated?

A

the Axon Hillock

56
Q

Remember

A

During the rising phase sodium enters the cell and during the falling phase potassium leaves the cells

57
Q

Action potential generation step by step

A
58
Q

Why doesn’t action potential travel in both directions?

A
  • Current is going through both slides
  • However, action potential only travels in one direction
  • This is because only certain sodium channels are activated
  • This means that it can only go one way as the other way has inactive sodium channels
59
Q

Why is myelination so important?

A

-Insulate action and make sure the signal is not lost by leaking out
-Faster propagation of the action potential

60
Q

Voltage gated channels occur only at …

A

the gaps of the myelin sheath called Nodes of Ranvier

61
Q

Depolarization occurs only at….

A

the nodes causing the Action Potential to jump from node to node along the axon

62
Q

Define the synapse

A

The synapse is the place where information is transmitted from one neuron to another

63
Q

Where do synapses form?

A

Between axon terminals and dendritic spines

There are also axon to axon, dendrite to dendrite and axon to cell body synapses

64
Q

Name the two types of synapses

A
  1. Electrical
    2.Chemical
65
Q

Define Electrical Synapses

A

Direct flow of electrical current from one cell to the next through gap junctions

66
Q

Define Chemical Synapses

A

Secrete neurotransmitter molecules that activate receptors

67
Q

True or False: Chemical synapses are faster than electrical synapses

A

False, chemical synapses are slower than electrical synapses as there are many points of intervention

68
Q

How do electrical synapses work?

A

The presynaptic and postsynaptic membranes are very close together and are actually physically connected by channel proteins forming gap junctions

69
Q

What is the importance of gap junctions?

A

Gap junctions allow current to pass directly from one cell to the next

In addition to the ions that carry this current, other molecules such as ATP can diffuse through the large gap junction pores.

70
Q

Describe some characteristics of electrical synapses

A

-There is no delay in transmission
-The signalling is bidirectional
-More reliable as they are less likely to be blocked

71
Q

What is the synaptic cleft?

A

The synaptic cleft, also known as the synaptic gap, is the space in between the axon of one neuron and the dendrites of another and is where the electrical signal is translated to a chemical signal that can be perceived by the next neuron.

72
Q

Define neurotransmitters

A

A chemical compound released by a neuron at a synapse and affects the transmembrane potential of another cell

73
Q

Chemical Synapses Chart

A
74
Q

Define neuromodulators

A

A chemical compound, released by a neuron, that adjusts the sensitivities of another neuron to specific neurotransmitters

75
Q

Is the outside of the membrane hydrophobic or hydrophilic?

A

Hydrophilic, the inside tails are hydrophobic

76
Q

Why does hyperpolarization occur?

A

Repolarization is caused by the closing of sodium ion channels and the opening of potassium ion channels.

Hyperpolarization occurs due to an excess of open potassium channels and potassium efflux from the cell. There are more K channels than Na channels

77
Q

How does an action potential start?

A

When neurotransmitters bind to the receptors on the dendrites of a neuron!

78
Q

Refractory Period Physiology

A

In its wake, the action potential leaves the Na+ channels inactivated and K+ channels activated for a brief time. These transitory changes make it harder for the axon to produce subsequent action potentials during this interval, which is called the refractory period.

79
Q

Absolute Refractory Period vs Hyperpolarization

A

absolute refractory period: The period from the opening of the sodium channels until the sodium channels begin to reset. hyperpolarization: A phase where some potassium channels remain open and sodium channels reset.

80
Q
A

BIO 202 Alara (2 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions