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PSGY1003 Biological Psychology > transmission within a neuron > Flashcards

transmission within a neuron Flashcards

1
Q

what is it meant by specialised cells?

A

cells are specialized according to their function

designed to carry out particular role in the body

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2
Q

define diffusion

A

movement of particles from an area of high concentration to an area of low concentration

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3
Q

what makes up the CNS?

A

brain and spinal cord

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4
Q

what makes up the PNS?

A

all other nerves

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5
Q

what is the role of sensory neurons?

A

carry information from body to interneurons

information includes:
light
sounds
smell

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6
Q

what is the role of interneurons?

A

link the sensory neurons to the motor neurons

process information from sensory neuron

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7
Q

what is the role of motor neurons?

A

carry information to the body from the CNS

important in controlling contraction of muscles

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8
Q

how many neurons are there in the brain?

A

86 billion

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9
Q

outline the structure of a (motor) neuron

A
  • soma
  • dendrites
  • axon
  • myelin sheath
  • terminal buttons
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10
Q

what is the soma of a neuron?

A

cell body

contains the nucleus of neuron

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11
Q

what are dendrites?

A
  • branches that connect to other neurons
  • receive messages from neurons
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12
Q

what are axons?

A
  • these carry information along action potential
  • from soma to terminal buttons
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13
Q

what is the myelin sheath?

A
  • wraps around the axon
  • allows electrical impulses to transmit quickly and efficiently
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14
Q

what are terminal buttons?

A
  • at the end of axon branches
  • responsible for sending the signal on to other neurons
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15
Q

what are the two types of cells?

A
  • neurons
  • supporting cells (glia)
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16
Q

identify types of glia

A
  • astrocytes
  • oligodendrocytes
  • microglia
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17
Q

explain the role of astrocytes

A
  • provide structural support to neurons
  • supply nutrients to neuron
18
Q

explain the role of oligodendrocytes

A
  • produce myelin sheath
  • this insulates axons
19
Q

explain the role of microglia

A
  • smallest supporting cells
  • important role in immune system of brain
  • attacks foreign tissue
20
Q

identify features of the process of transmission within a neuron

A
  • electrical process
  • aim is to get message from soma down to terminal button
  • involves the movement of ions across the cell membrane
  • cells are more negative on the inside than on the outside
  • this causes a resting potential
21
Q

describe the cell membrane

A
  • made up of two layers of phospholipid molecules
  • head of phospholipid is hydrophilic
  • tail of phospholipid is hydrophobic
  • contains an ion channel which spans the membrane
  • ion channel allows ions to move in and out of cell
22
Q

what is the name of the fluid outside of the cell membrane?

A

extracellular fluid

23
Q

what is the name of the fluid inside of the cell membrane?

A

intracellular fluid

24
Q

what are ions?

A

charged molecules

25
Q

identify the two types of ions

A

cations

anions

26
Q

what are cations?

A

positively charged ions

27
Q

what are anions?

A

negatively charged ions

28
Q

what molecules does intracellular fluid contain?

A

potassium (K+)

anions (A-)

29
Q

what molecules does extracellular fluid contain?

A

sodium (Na+)

chloride (Cl-)

30
Q

what is the membrane potential?

A

the difference in electrical potential inside and outside the cell

31
Q

how is the membrane potential balanced?

A
  • diffusion
  • electrostatic pressure
    (attraction of particles that are opposite and repulsion of particles that are the same charge)
32
Q

explain how the membrane potential is balanced

A

ANIONS
- anions are inside the cell and cannot leave

  • results in negative inside of cell

POTASSIUM
- potassium ions are more concentrated inside cell

  • potassium ions want to move out of cell membrane by diffusion
  • potassium is attracted to inside due to electrostatic pressure therefore forces balance and K+ doesn’t move

CHLORIDE
- more concentrated outside cell

  • wants to move inside by diffusion
  • repelled from inside due to electrostatic pressure therefore doesn’t move

SODIUM
- more concentrated outside the cell

  • wants to move in by diffusion
  • attracted to inside due to electrostatic pressure
  • both processes force Na+ into cell
  • kept under control by sodium-potassium pumps in cell membrane
  • 3 sodium ions pumped out and 2 potassium ions pumped in
33
Q

what is a resting potential?

A

the electrical potential difference across plasma membrane when in a non-excited state

resting potential of neuron is =70 mV

34
Q

why is it important for resting potential to be maintained?

A

so that neuron can respond rapidly to stimulus

35
Q

what is an action potential?

A

a rapid change in membrane potential

it is an ‘all or nothing’ process

36
Q

define depolarization

A

a decrease from normal resting potential (brings membrane closer to 0)

37
Q

define hyperpolarization

A

an increase relative to resting potential (more negative)

38
Q

describe the process of the action potential

A
  • threshold of excitation met
  • voltage-gated sodium channels open
  • sodium enters
  • inside membrane becomes MORE positive than outside
  • voltage-gated potassium channels open
  • potassium leaves the cell
  • membrane potential reaches +40 mV
  • sodium channels become refractory and no more sodium enters
  • potassium continues to leave cell
  • membrane potential returns to resting level
  • potassium channels close and sodium channels reset
  • extra potassium outside cell diffuses away
39
Q

define propagation

A
  • refers to the way the action potential is transmitted down an axon
  • action potential can only go in one direction
  • action potential doesn’t move but rather causes new action potential
40
Q

define saltatory conduction

A
  • refers to the way action potential is regenerated along the axon at nodes of Ranvier
41
Q

what are the benefits of saltatory conduction

A

fast conduction

more energy efficient

PSGY1003 Biological Psychology (21 decks)

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