Neuroscience I

Question 1

Neuron

Answer 1

fundamental building block of the nervous system

Question 2

Receptive Zone of Neuron

Answer 2

Designed to receive signals from other neurons.
- Made up of dendrites branching out from the cell body

Question 3

Dendrites

Answer 3

Projections that extend from the core of the neuron
- reach out to other neurons and receive signals

Question 4

Cell Body

Answer 4

Carries genetic information, maintains structure, and provides energy to keep the neuron functioning

Question 5

Transmission Zone of Neuron

Answer 5

Designed to pass on signals to other cells.
- Made up of the axon and axon terminal

Question 6

Axon

Answer 6

A long fiber
- Once the neuron receives a signal, it is pass down the axon which varies in length.

Question 7

Terminal Ends

Answer 7

Reach out and make connections with the receptive zone of nearby neurons to transmit the signal further

Question 8

Glial Cell

Answer 8

Found throughout the nervous system to provide the structural support, nourishment, and insulation needed by the neurons

Question 9

Cell membrane

Answer 9

Allowing different ions to pass through it with various levels of ease

Question 10

Leak Potassium Channel

Answer 10

Allows positively charged potassium to pass through the cell membrane and out of the neuron

Question 11

Ligand-Gated Sodium Channel

Answer 11

Only open when some other chemical or ligand interacts with them

Question 12

Resting potential

Answer 12

-70mv

Question 13

Action potential

Answer 13

Fundamental unit of communication for neurons
- triggered at -50mv

Question 14

The rise

Answer 14

Voltage-gated Na channels begin to open
- +Na rush into neuron
- Pushes +K out of cell through leak channels
Voltage-gated K open due to charge build up

Question 15

Symbols

Answer 15

K = potassium
Na = Sodium

Question 16

Peak

Answer 16

+40mv
voltage-gated sodium channels close

Question 17

The Fall

Answer 17

Na stops entering
K leaves through voltage gated K channel
Undershoots -70mv, closing voltage gated K channel

Question 18

Absolute refractory period

Answer 18

begins immediately once an action potential is initiated and ends once the membrane potential dips back below -50m

Question 19

Relative refractory period

Answer 19

begins after the absolute refractory period ends, and lasts until resting potential is re-established
a time where it’s harder, but not impossible, to initiate a new action potential
- sodium channels are able to open

Question 20

Refractory period

Answer 20

neuron cannot fire another action potential to recover

Question 21

Sodium Potassium Pump

Answer 21

expels three sodium ions from the intracellular fluid and replaces them with two potassium ions
- to maintain ion balance of neuron

Question 22

Synapse

Answer 22

Special mechanisms exist to transmit a signal from the presynaptic neuron to the receiving postsynaptic neuron

Question 23

Nodes of Ranvier

Answer 23

limit when the ions of the action potential can dissipate into the surrounding

Question 24

Oscilloscope Record

Answer 24

Message is encoded as frequency and pattern of action potentials

Question 25

Neurotransmitters

Answer 25

A variety of chemicals within the terminal end of the presynaptic neuron.
- Found within small intracellular containers called vesicles
- A single neurotransmitter can also have multiple functions, depending on the receptor

Question 26

Vesicles

Answer 26

• Arrival of the action potential causes some of the vesicles within the neuron to move towards the cell membrane of the presynaptic neuron
• vesicle fuses with membrane of neuron and spills out neurotransmitters

Question 27

Synaptic Cleft

Answer 27

The neurotransmitter molecules float freely in the cleft along with a number of other molecules which can have direct effects on the neurotransmitter

Question 28

Postsynaptic Neuron

Answer 28

The free neurotransmitter molecules in the cleft can bind to their specific receptors to continue the process of signal transmission by several possible actions

Question 29

Excitatory Postsynaptic Potential (EPSP)

Answer 29

Sodium channels open, allowing +Na to flow in to depolarize cell
Number of EPSPs must occur to trigger action potential

Question 30

Temporal Summative

Answer 30

One presynaptic neuron generates multiple ESPs one after another onto the same postsynaptic neuron

Question 31

Spatial Summation

Answer 31

If multiple EPSPs are generated simultaneously from several different presynaptic neurons making connections with the same postsynaptic neuron

Question 32

Inhibitory Postsynaptic Potential (IPSP)

Answer 32

Cl channels open, allowing -Cl to enter
Hyper-polarizing cell
Making it less likely to trigger AP
- Method brain uses to communicate through complex patterns and networks to control everything from your thoughts and emotions

Question 33

When does development begin

Answer 33

18 days after conception
- outter layer of embryo begins to thicken

Question 34

Development day 21

Answer 34

Plate curl and fuse together forming neural tube
- tube closed by 28

Question 35

Development week 20

Answer 35

Cells begin to look like brain

Question 36

Development day 28-42

Answer 36

cell division is said to be symmetrical as the division of each founder cell leads to two identical founder cells

Question 37

Development day 42-125

Answer 37

cell division is asymmetrical as the dividing founder cell now produces one founder cell that stays put along with a cell that will become a neuron or glial cell, which migrates outward from the ventricular zone

Question 38

When does neural migration begin

Answer 38

begins almost immediately after the first neurons are born at day 42 and continues for about 6 weeks after the last neuron is born

Question 39

Neural differentiation is affected by..

Answer 39

Genetics
Environment (surrounding cells, external environment)