Neurons, Synapses, and Signaling

Question 1

Presynaptic cell

Answer 1

• Cell body (has most neurons organelles)
• Dendrites (branches of trees, receive signals)
• Axon (a long extension, transmit signals)
• Glial cells/glia

Question 2

Postsynaptic cell (receiver)

Answer 2

• Synapse
• Neurotransmitters pass info from the transmitting neuron to the receiving cell.
• synaptic terminals
• Glial cells/Glia

Question 3

2 types of glial cells

Answer 3

• Astrocytes

- Oligodendrocytes

Question 4

3 steps of information processing in neuron system

Answer 4

• Sensory input/sensory neuron
• Intergration/interneuron
• Motor output/motor neuron

Question 5

What neuron carry out intergration

Answer 5

• Central nervous system (CNS)

Question 6

What neuron carry out input and output

Answer 6

• Peripheral nervous system (PNS)

Question 7

Membrane potential

Answer 7

• attracts opposite charges, potential energy (-50 to -100mV)

Question 8

Resting potential

Answer 8

• not sending a signal ( -60 to -80mV)

Question 9

What types of ions and pump play an important role in resting potential

Answer 9

• Potassium ions and sodium ions. Every 3 sodium out, 2 potassium in
• Their channels

Question 10

Are there more Na channels or K channels

Answer 10

• K channels, thats why resting potential is closer to Ek than Ena

Question 11

Ek negative or positive

Answer 11

• Negative

Question 12

What is equilibrium potential (Eion)

Answer 12

• the membrane voltage for a particular ion at equilibrium and can be calculated using the Nernst equation

Question 13

Ena is negative or positive

Answer 13

• Positive

Question 14

What causes changes in membrane potential

Answer 14

• Gated ion channels that open and close in order to response a specific stimuli

Question 15

What is hyperpolarization

Answer 15

• An increase in magnitude of membrane potential (more negative inside)

Question 16

What is depolarization

Answer 16

• A decrease in magnitude of membrane potential (less negative inside)

Question 17

Graded potential

Answer 17

• Cause a smal magnitude change by hyperpolarizations

Question 18

Action potential

Answer 18

• A big jump cause by depolarization, conducted by the axons

Question 19

Generation of action potentials

Answer 19

• Resting state: all K and Na channels closed, ungated channels maintain resting potential
• Gated Na channels opens as it becomes depolarization
• Rising phase
• Falling phase: most Na channels become inactivated, and most K channels open
• Undershoot: Na channels closed, some K channels still open

Question 20

Refractory period

Answer 20

• After the action potential, further stimulus has no effect

Question 21

What cause refractory period

Answer 21

• Temporary inactivation of Na channels

Question 22

What site the action potential is generated

Answer 22

• Axon hillock

Question 23

In what direction does action potential travel

Answer 23

Toward the synaptic terminals

Question 24

What prevent action potential from travelling backwards

Answer 24

• Inactivated Na channels

Question 25

The speed of action potential increase proportionally to what

Answer 25

- Axon's diameter

Question 26

What is myelin sheath

Answer 26

- It is made by glia oligodendrocytes in the CNS and Schwann cells in the PNS

Question 27

Myelin sheath in action potential

Answer 27

- It insulates axons and help action potential speed increase

Question 28

What position on the axons action potentials form

Answer 28

- Nodes of Ranvier (gaps between myelin sheath)

Question 29

What is the process of action potentials jumping from node to node called

Answer 29

- Saltatory conduction

Question 30

Where does the transmission of information from neurons to other cells occur

Answer 30

- At the synapses

Question 31

At electrical synapses

Answer 31

- the electrical current flows from one neuron to another | - found in heart and brain

Question 32

At chemical synapses

Answer 32

- a chemical neurotransmitter carries information across the gap junction

Question 33

Most synapses are chemical or electrical

Answer 33

- Chemical

Question 34

What gated channels involved in chemical synapses

Answer 34

- Ca channels

Question 35

2 postsynaptic potentials

Answer 35

- Excitatory postsynaptic potentials: depolarization | - Inhibitory postsynaptic potentials: hyperpolarization

Question 36

After being released from the synaptic vesicles, neurotransmitter will

Answer 36

- diffused out of the synaptic cleft - taken up by surrounding cells - degraded by enzymes

Question 37

What is temporal summation

Answer 37

Two excitatory post synapsis potentials are produced and cause a jumping over threshold

Question 38

Spatial summation

Answer 38

- Two spontaneous excitatory post synapsis produced

Question 39

Five groups of neurotransmitters

Answer 39

- Acetylcholine - Biogenic amines - Amino acids - Neuropeptides - Gases

Question 40

Some nervous system disorder

Answer 40

- Parkinson | - Alzheimer