Neuronal Function

Question 1

excitable cells that are important in signaling
(electrical and chemical), coordination and movement (cell body, dendrites and axon)

Answer 1

Neurons (Nerve Cells)

Question 2

3 types of neurons and their functions

Answer 2

Sensory - Transmit information and respond to stimuli

Interneurons - Connect other neurons within the CNS

Motor - Carry signals to effector organ

Question 3

Components of the nervous system

Answer 3

Neurons and Neuroglia

Question 4

These are the supporting cells in the nervous system

Answer 4

Neuroglia (glial cells)

Question 5

Parts of the neuron and their functions

Answer 5

Soma - Cell Body; Responsible for metabolic maintenance of cell

Dendrites - Receives signals from other neurons

Axon - conduct signals away from the body

Question 6

include the astrocytes, oligodendrocytes, microglia, and ependymal cells

Answer 6

Glial cells

Question 7

Steps in transmission of signals in a single neuron

Answer 7

1. Dendrites and cell body receive and integrate information.
2. Axon hillock is the trigger zone. Action potentials travel from hillock to terminals.
3. Action potentials move along the axon’s surface.
4. Action potentials in axon terminals trigger neurotransmitter release, transmitting signals to other cells.

Question 8

collect from and send out information to other neurons

Answer 8

Sensory Neurons (Afferent Neuron)

Question 9

Axons of afferent neurons are called?

Answer 9

Afferent Fiber

Question 10

Lie inside the Central Nervous System and carry information between other neurons

Answer 10

Interneurons

Question 11

Specialized location where information is passed

Answer 11

Synapses

Question 12

Neurons that carry the information out to the effectors

Answer 12

Motor (Efferent) Neurons

Question 13

potential difference across the membrane
(separation of charges across the membrane)

Answer 13

Membrane Potential (Vm)

Question 14

What governs the electrical properties of the membrane

Answer 14

Unequal distribution key ions between the ICF and ECF and their selective movement through the plasma membrane

Question 15

Different parts of the membrane potential graph and what they mean (3)

Answer 15

Depolarization - Decrease in potential; les negative

Repolarization - Return to resting potential post depolarization

Hyperpolarization - Increase in potential; membrane more negative

Question 16

passive movement of current across the cell
membrane

Answer 16

electrotonic conduction

Question 17

Passive change in Vm depends on

Answer 17

K+ leak channels

Question 18

hindrance to electrical
charge movement/ measure of
impermeability to ions

Answer 18

Resistance

Question 19

measure of the amount of
charge that can be maintained across an
insulating gap

Answer 19

Capacitance

Question 20

spread by passive current flow and are impeded by resistances; die out over short distances

Answer 20

Graded Potentials

Question 21

Active change in Vm depends on

Answer 21

The opening or closing of gated ion selective
channels

Question 22

voltage difference across cell membrane

• Ion concentration gradient in and out of the cell
• Selective permeability of ion channels

Answer 22

Electrochemical Potentials

Question 23

concentration gradient and electrical potential difference are balanced/equal

Answer 23

Electrochemical Equilibrium

Question 24

potential difference across the membrane that balances the concentration gradient

Answer 24

Equilibrium Potential

Question 25

used in calculating equilibrium potential for single ions

Answer 25

Nernst Equation

Question 26

used in calculating equilibrium potential for multiple ions

Answer 26

Goldman Equation

Question 27

Potential difference at equilibrium (non-excited or resting state), Vrest

Answer 27

Resting Potentials

Question 28

Factors affecting Vrest

Answer 28

- Selective Ion channel - Unequal distribution of ions in and out of cell

Question 29

Rapid, brief, large changes in membrane potential (Vm) that are propagated along axons

Answer 29

Action Potentials

Question 30

Factors affecting Action potentials

Answer 30

- Unequal concentrations across membranes caused by active transport of ions - Electrochemical gradient across membranes - Selective gating of ion channels

Question 31

membrane potential that triggers AP (-50 to -55mV); critical all-or-none event

Answer 31

Threshold potential

Question 32

States that an excitable membrane either responds to a triggering event with a maximal action potential that spreads non-decrementally through-out the membrane, or it does not respond with an action potential at all.

Answer 32

All-or-none Law

Question 33

Types of conduction

Answer 33

Contiguous and Saltatory

Question 34

spread of the AP along every patch of membrane down the length of the axon

Answer 34

Contiguous Conduction (contiguous means “touching” or “next to in sequence”)

Question 35

new action potential cannot be initiated by normal events. Prevents backward flow Limits AP frequency

Answer 35

Refractory Period

Question 36

membrane is completely refractory (unresponsive) to further stimulation

Answer 36

Absolute Refractory Period

Question 37

Second Action Potential can be produced by strong triggering event

Answer 37

Relative Refractory Event

Question 38

Action potential are speeded up by myelination, this is done by these two myelin forming cells

Answer 38

Oligodendrocytes (CNS) and Schwann Cells (Non-CNS)

Question 39

Conduction in myelinated fiber, impulse “jumps” from node to node

Answer 39

Saltatory Conduction

Question 40

Non-gated ion channels

Answer 40

Leak Channels

Question 41

Ion Channels that open or close in response to specific triggering events

Answer 41

Gated Channels

Question 42

Two basic forms of electrical signal

Answer 42

Graded (Short distance/decay over time) and Action Potential (longer distance/no decay)

Question 43

Portion of the Membrane potential graph vs time graph where the membrane potential becomes positive

Answer 43

Overshoot

Question 44

Portion of the membrane potential vs time graph where the membrane potential is more negative than the resting potential

Answer 44

Hyperpolarization

Question 45

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