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PSYC 302 > Chapter 1 - Quiz 1 > Flashcards

Chapter 1 - Quiz 1 Flashcards

1
Q

1.1: Neurons and glia

What are the two kind of cells that make up the nervous system?

A

-neurons and glia

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2
Q

1.1: Neurons and glia

What are neurons/what do they do?

A

-cells that receive information and transmit it to other cells

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3
Q

1.1 - 1a Neurons and glia: Santiago Ramon y Cajal, a Pioneer of Neurosci

Who are the pioneers/main founders of neuroscience?

A

-Charles Sherrington & Santiago Ramon y Cajal

-Santiago demonstrated (via stained slides) that neurons are seperate

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4
Q

1.1 -1b Neurons and Glia: The structures of an animal cell

What is the surface of a cell called? Define it. (2)

A

-membrane
-separates inside of the cell from outside

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5
Q

1.1 -1b Neurons and Glia: The structures of an animal cell

What does the nucleus contain? What cells do not have a nucleus? (2)

A

-chromosomes
-mammalian red blood cells

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6
Q

1.1 -1b Neurons and Glia: The structures of an animal cell

Define mitochondrion. What does it do? (1)

A

-performs metabolic activities, providing the energy that the cell uses for all activites

-mitochondria have genes seperate from those in the nucleus of a cell and mitochondria differ from one another genetically

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7
Q

1.1 -1b Neurons and Glia: The structures of an animal cell

What do ribosomes do?

A

-synthesizes new protein molecules

-some ribosomes float freely in the cell, others are attached to the endoplasmic reticulum

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8
Q

1.1 -1b Neurons and Glia: The structures of an animal cell

What is the endoplasmic reticulum?

A

-network of thin tubes that transport newly synthesized proteins

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9
Q

1.1 -1c Neurons and Glia: The structures of a neuron

What do all neurons have? What do most have? (2)

A

-soma (cell body)
-most have dendrites, axon, and presynaptic terminals

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10
Q

1.1 -1c Neurons and Glia: The structures of a neuron

Where is a motor neuron and where does it recieve and send an excitation? (3)

A

-soma in the spinal cord
-receives excitation through its dendrites
-conducts impulses along its axon to a muscle

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11
Q

1.1 -1c Neurons and Glia: The structures of a neuron

Where is a sensory neuron and what type of stimulation does it respond to? Where is the soma? (3)

A

-neurons in skin, tongue, ear, smell
-specialized to be highly sensitive to a particular type of stimulation on one end
-soma is in the middle of two axons

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12
Q

1.1 -1c Neurons and Glia: The structures of a neuron

What are dendrites?

A

-branching fibers that get narrower near their ends

-dendrites surface is lined with specialized synaptic receptors at which the dendrite recieves information from other neurons. The greater the surface area of a dendrite, the more information it can receive.

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13
Q

1.1 -1c Neurons and Glia: The structures of a neuron

What do many dendrites contain? Define them. (2)

A

-dendritic spines
-short outgrowths that increase the surface area available for synapses

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14
Q

1.1 -1c Neurons and Glia: The structures of a neuron

What does a cell body contain?

A

-nucleus, ribosomes and mitochondria

-most of a neuron’s metabolic work occurs here
-in many neurons, the cell body is like the dendrites, covered with synapses on its surface

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15
Q

1.1 -1c Neurons and Glia: The structures of a neuron

What is the axon? Where does it convey impulses to? (2)

A

-the thin fiber of constant diameter
-to other neurons, an organ, or a muscle

-axons can be more than a meter in length
-neurons can only have one axon
-the largest animals will have the largest axons

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16
Q

1.1 -1c: Neurons and Glia: The structures of a neuron

What are many vertebrate axons covered with?

A

-myelin sheath with nodes of Ranvier

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17
Q

1.1 -1c: Neurons and Glia: The structures of a neuron

What is the presynaptic terminal (end bulb)?

A

-it is at the end of each branch of axon and is the swelling

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18
Q

1.1 -1c: Neurons and Glia: The structures of a neuron

What is an afferent axon?

A

-brings info towards something

-a for admit

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19
Q

1.1 -1c: Neurons and Glia: The structures of a neuron

What is an efferent axon?

A

-carries info away from something

-e for exit

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20
Q

1.1 -1c: Neurons and Glia: The structures of a neuron

What is an interneuron cell/intrinsic neuron?

A

-a cell whose dendrites and axons are entirely contained within a single structure

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21
Q

1.1 -1e: Neurons and Glia: Glia

Where do glia outnumber neurons and vice versa? (3)

A

-glia outnumber them in the cerebral cortex
-neurons outnumber glia in several other areas of the brain, especially the cerebellum
-in total, the numbers are about equal

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22
Q

1.1 -1e: Neurons and Glia: Glia

What are the different types of glia cells?

A

-astrocytes
-oligodendrocytes
-microglia
-Schwann cells
-radial glia

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23
Q

1.1 -1e: Neurons and Glia: Glia

What are astrocytes? Where do they go? What do they allow to happen? (3)

A

-star shaped glia that synchronize the activity of the axons
-wrap around the synapses of functionally related axons
-helps synchronize neurons, enabling their axons to send messages in waves

-important for generating rhythms like breathing

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24
Q

1.1 -1e: Neurons and Glia: Glia

What is the tripartite synapse?

A

-tip of axon releases chemicals that cause the neighboring astrocytes to release chemicals of their own, magnifying the next message to the next neuron

-possible contributor to learning or memory

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25
Q

1.1 -1e: Neurons and Glia: Glia

Define microglia? What are two other functions they perform?

A

-cells that remove waste material and other microorganisms from the nervous system
-they proliferate after brain damage, removing dead or damaged neurons
-they contribute to learning by removing the weakest synapse

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26
Q

1.1 -1e: Neurons and Glia: Glia

Which cells build the myelin sheaths that surround and insulate certain vertebrae axons? And supply an axon with nutrients necessary for proper functioning?

A

-oligodendrocytes in the brain and spinal cord
-Schwann cells in the periphery of the body

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27
Q

1.1 -1e: Neurons and Glia: Glia

What do radial glia do?

A

-guide the migration of neurons and their axons and dendrites during embryonic development

-once embryological development finishes, most radial glia differentiate into neurons and sometimes astrocytes and oligodendrocytes

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28
Q

1.1 - 2 The Blood Brain Barrier

What is the blood-brain barrier?

A

-the mechanism that excludes most chemicals from the vertebrate brain

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29
Q

1.1 - 2a Blood Brain Barrier: Why we need a blood-brain barrier

Why do we need a blood-brain barrier? What is the blood-brain barrier? (2)

A

-to minimize the risk or irreparable brain damage
-the brain’s blood vessel are lined with tightly packed endothelial cells that keep out most viruses, bacteria and harmful chemicals

30
Q

1.1 - 2a Blood Brain Barrier: Why we need a blood-brain barrier

What are examples of a virus that does cross the blood-brain barrier?

A

-rabies, herpes, chicken pox

31
Q

1.1 - 2b Blood Brain Barrier: How the blood-brain barrier works

What is the con of the blood-brain behavior? (2)

A

-it keeps out both good and bad chemicals
-including keeping out fuels and amino acids, which the brain needs special mechanisms to help cross

32
Q

1.1 - 2b Blood Brain Barrier: How the blood-brain barrier works

Which molecules cross the blood-brain barrier easily? (2)

A

-small uncharged molecules (oxygen, carbon dioxide)
-molecules that dissolve in the fats of the membrane (vit A and D, psychiatric drugs)

-the speed a drug takes effect depends largely on how readily it dissolves in fats and therefore crosses the blood-brain barrier

33
Q

1.1 - 2b Blood Brain Barrier: How the blood-brain barrier works

How does water cross the blood-brain barrier?

A

-through special protein channels in the wall of the endothelial cells

-considered passive transport

34
Q

1.1 - 2b Blood Brain Barrier: How the blood-brain barrier works

What is active transport? Which chemicals have to be actively transported into the brain? (2)

A

-a protein-mediated process that expends energy to pump chemicals from the blood into the brain
-glucose, amino acids, purines, choline, a few vitamins and iron

-glucose is the brains main fuel
-insulin and probably certain other hormones also cross the blood-brain barrier

35
Q

1.1 - 3 Nourishment of Vertebrate Neurons

Why do neurons need a steady supply of oxygen?

A

-because metabolizing glucose requires oxygen and vertebrate neurons depend almost entirely on glucose

36
Q

1.1 - 3 Nourishment of Vertebrate Neurons

Why do neurons depend so much on glucose?

A

-because its the only nutrient that crosses the blood-brain barrier in large amounts

37
Q

1.1 - 3 Nourishment of Vertebrate Neurons

What does vitamin B1 (thiamine) sufficiency result in?

A

-to use glucose, the body needs B1, so a lack of this leads to death of neurons and a condition called Korsakoff’s syndrome

38
Q

1.2 The Nerve Impulse

How do two flashes on the retina in different spots avoid being received at different times?

A

-axons from more distant parts of your retina transmit impulses slightly fasters than those closer to the brain

39
Q

1.2 - 1 The resting potential of the neuron

What is the membrane of a neuron composed of?

A

-two layers of phospholipid molecules with cylindrical protein molecules through which chemicals can pass through

40
Q

1.2 - 1 The resting potential of the neuron

What is an electrical gradient or polarization?

A

-a difference in electrical charge between the inside and outside of the cell

41
Q

1.2 - 1 The resting potential of the neuron

Define resting potential

A

-condition of a neuron’s membrane when it has not been stimulated or inhibited

42
Q

1.2 - 1 The resting potential of the neuron

How do you measure the resting potential of a neuron?

A

-inserting a very thin microelectrode into the cell body and connecting this to a voltmeter

43
Q

1.2 - 1a Forces Acting on Sodium and Potassium Ions

How is a neuron able to stay at its resting potential? At rest, what ions pass through the selective membrane? (2)

A

-the selective permeability ensure chemicals stay where they are supposed to be
-at rest, almost no sodium ions cross the membrane except by the sodium-potassium pump but some potassium ions slowly leak out

-the leakage of the potassium ions increases the electrical gradient

44
Q

1.2 - 1a Forces Acting on Sodium and Potassium Ions

What is a sodium-potassium pump? How many sodium ions leave the cell per potassium ions entering from the sodium-potassium pump? (3)

A

-mechanism that actively transports sodium ions out of the cell and potassium ions in
-3 sodium ions out of the cell
-2 potassium ions in the cell

-as a result of the sodium-potassium pump, sodium ions are more than 10 times more concentrated otuside the membrane than inside, and potassium ions are more concetrated inside than outside

45
Q

1.2 - 1a Forces Acting on Sodium and Potassium Ions

What is the concentration gradient?

A

-the difference in distribution of ions across the membrane

-sodium is more concentrated outside than inside, so just by the laws or probability, sodium is more likely to enter the cell than leave it

46
Q

1.2 - 1a Forces Acting on Sodium and Potassium Ions

Why at rest does no sodium enter into the cell?

A

-because the sodium channels are closed when the membrane is at rest

-if they weren’t closed, sodium would enter rapidly because of the electrical and concentraion gradient

47
Q

1.2 - 1a Forces Acting on Sodium and Potassium Ions

What two processes work to move sodium ions into the cell? (2)

A

-the electrical gradient (the negative charge inside attracts the positive sodium)
-the concentration gradient (sodium is more concentrated outside than inside, so just because of probability sodium is more likely to enter the cell than to leave it)

48
Q

1.2 - 1a Forces Acting on Sodium and Potassium Ions

How is potassium subject to competing forces?

A

-the electrical gradient tends to pull it in
-the concentration gradient tends to drive it out

49
Q

1.2 - 1a Forces Acting on Sodium and Potassium Ions

Does the inside of a neuron have negatively charged ions too? How about outside the cell, which ions are those? (2)

A

-yes, they sustain the membranes polarization
-outside the cell there are chloride ions

50
Q

1.2 - 1b Why a resting potential?

Why is a resting potential necessary or useful?

A

-it prepares the neurons to respond rapidly

-because the membrane did its work in advance by maintaining the concentration gradient for sidum, the cell is prepared to respond vigorously to a stimulus

51
Q

1.2 - 2 The Action Potential

Define action potential. Define hyperpolarization. Define depolarize. (3)

A

Action potential: all or none messages sent by axons
Hyperpolarization: increased polarization across a membrane
Depolarize: to make the polarization go towards zero, make it less negative

52
Q

Define threshold. What happens when the potential rechaes the threshold? Can the intensity of a stimulus cause the neuron to produce a bigger or smaller action potential? (3)

A

-minimum amount of membrane depolarization necessary to trigger an action potential
-the membrane opens its sodium channels and lets sodium ions into the cell
-no, the action potential will always be the same intensity and velocity if it passes the threshold

-it is all or none, and any stimlation beyond the threshold, regardless of how far beyond, produces the same response

53
Q

1.2 - 2a The Action Potential: The all or none law

Define the all-or-none law

A

-the amplitude and velocity of an action potential is independent of the intensity of the stimulus that initiated it, provided that the stimulus reaches the threshold

-thicker axons convey action potentials at greater velocities and can convey more action potentials per second

54
Q

1.2 - 2a The Action Potential: The all or none law

How does an action potential signal the difference between a weak and strong stimulus?

A

-it changes the timing and can use almost a morse code rhythm

55
Q

1.2 - 2b The Action Potential: The molecular basis of the action potenti

The axon channels regulating sodium and potassium are what? Define this word. (2)

A

-voltage gated channels
-membrane channel whose permeability to the ion depends on the voltage difference across the membrane

56
Q

1.2 - 2b The Action Potential: The molecular basis of the action potenti

State the steps of an action potential and what happens to the ions during each step from resting potential to the end. (6)

A

Resting potential:sodium channels are fully closed, potassium channels are almost closed, allowing a little flow of potassium
Depolarization: Both sodium and potassium channels open, but potassium doesn’t really move yet. Sodium ions are driven into the cell.
Threshold: Once depolarization reaches the threshold, the sodium channels completely open and sodium enters rapidly.
Peak of action potential: Sodium gates close. Potassium is driven out of the cell know.
Hyperpolarization: The potassium leaving eventually creates a hyperpolarization of the membrane.
After action potential: The membrane has returned to its resting potential but there are more sodium ions inside the cell and slightly fewer potassium ions than before. The sodium-potassium pump restores the original distribution.

57
Q

1.2 - 2b The Action Potential: The molecular basis of the action potenti

How do local anesthetics work? (2)

A

-they attach to the sodium channels of the membrane and prevent sodium ions from entering
-when a dentist administers Novocain before drilling into a tooth, your receptors are screaming pain but the axons cannot transmit the message to your brain so you don’t feel it

58
Q

1.2 - 3 Propogation of the action potential

What does the propagation of the action potential describe? How does it work? (2)

A

-the transmission of an action potential down an axon
-as an action potential occurs at one point on the axon, enough sodium enters to depolarize the next point to its threshold, producing an action potential at that point. In this manner the action potential flows along the axon remaining at equal strength throughout. Behind each area of sodium entry, potassium ions exit, restoring the resting potential

59
Q

1.2 - 3 Propogation of the action potential

What is back-propogating?

A

-when the action potential starts, it back-propagates into the cell body and dendrites

-an action potential always starts in an axon and propagates without loss from start to finish

60
Q

1.2 - 3 Propogation of the action potential

Why is back-propagation important?

A

-when an action potential back-propagates into a dendrite the dendrite becomes more susceptible to the structural changes responsible for learning

61
Q

1.2 - 4 The Myelin Sheath and Saltatory Conduction

What is a myelin sheath and what purpose does it serve? What analogy describes it? (3)

A

-an insulating material composed of fats and proteins
-it increases the speed of an action potential
-analogy of throwing a ball over a long distance

62
Q

1.2 - 4 The Myelin Sheath and Saltatory Conduction

What are myelinated axons?

A

-the axons covered by a sheath with small breaks called nodes of Ranvier

-node of ranvier is like the exposed axon.

63
Q

1.2 -3 The Myelin Sheath and Saltatory Conduction

Why does saltatory conduction happen? What is saltatory conduction? What are the pros of saltatory conduction? (4)

A

-a myelinated axon with an action potential can’t propagate along the myelinated regions.
-Instead, the action potential “jumps” from one node of Ranvier to the next.
-This jumping process is much faster than if the action potential had to propagate along the entire length of the axon.
-as well, it expends less energy

64
Q

1.2 - 4a The myelin sheath and saltatory conduction: the refractory peri

Define a refactory period. When does it happen? (2)

A

-time when the cell resists the production of further action potentials
-After an action potential, neuron enters refractory period.

-Voltage-gated sodium channels inactive, cannot open.
-Prevents immediate firing of another action potential.
-Ensures one-directional signal transmission.
-Then what prevents an action potential near the center of an axon from reinvading the areas that it has just passed? The answer is that the areas it just passed are still in their refractory period.

65
Q

1.2 - 4a The myelin sheath and saltatory conduction: the refractory peri

What can a refractory period be broken down into?

A

-the absolute refractory period (stage 1)
-the relative refractory period

66
Q

1.2 - 4a The myelin sheath and saltatory conduction: the refractory peri

What is the absolute refractory period?

A

-this means the membrane cannot produce another action potential, regardless of the stimulation

-about 1 ms long

67
Q

1.2 - 4a The myelin sheath and saltatory conduction: the refractory peri

What is the relative refractory period?

A

-a stronger than usual stimulus is needed to initiate an action potential

-about 2-4 ms

68
Q

1.2 - 4a The myelin sheath and saltatory conduction: the refractory peri

What two facts does the refractory period depend on?

-to stay in a refractory period

A

-the sodium channels are closed
-potassium is flowing out of the cell at a faster than usual rate

69
Q

1.2 -5 Local Neurons

How do small neurons exchange information without an axon and what are they subsequently called? What do they not follow subsequently because they do not have an axon? (3)

A

-since they have no axons, they can only exchange info with their neighbors
-they are called local neurons
-they do not follow the all-or-none law

-local neurons are neurons without an axon

70
Q

1.2 -5 Local Neurons

What is a graded potential?

A

-a membrane potential that varies in magnitude in proportion to the intensity of the stimulus

-local neurons have this

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