3.1

Question 1

What is a neuron?

Answer 1

Cells that receive, integrate, and transmit information in the nervous system. They are powered by electrical impulses and communicate with other nerve cells through chemical signals.

Question 2

How do neurons communicate?

Answer 2

They communicate selectively with other neurons to form neural networks.

Question 3

Entire nervous system divided into which two units? What do they consist of?

Answer 3

Central Nervous System (CNS) - brain + spinal cord

Peripheral Nervous System (PNS) - all other nerve cells in rest of body

Question 4

3 Types of Neurons

Answer 4

Sensory Neurons: (afferent neurons) detect information from the physical world and pass that information to the brain

Motor Neurons: (efferent neurons) direct muscles to contract or relax, thereby producing movement.

Interneurons: Only communicate with other neurons (instead of other brain structures or body organs)

Question 5

What are the 4 structural regions of neurons?

Answer 5

Dendrites, Cell Body, Axon, Terminal Buttons

Question 6

Dendrites

Answer 6

Branchlike extensions of the neuron that detect information from other neurons

*Dendrites (Dentures/teeth) where food is put in and received )

Question 7

Cell Body

Answer 7

(Soma) Site in the neuron where information from thousands of other neurons is collected and integrated.

Question 8

Axon

Answer 8

A long narrow outgrowth of a neuron by which information is transmitted to other neurons.

*(Ax)on -Axes cut down branches…Axons branch out to other nuerons

Question 9

Terminal Buttons

Answer 9

Small nodules, at the end of axons, that release chemical signals from the neuron into the synapse.

Question 10

Synapse

Answer 10

The site at which chemical communication occurs between neurons.

Question 11

Synaptic Cleft

Answer 11

The gap between the axon of a “sending” neuron and the dendrites of a “receiving” neuron; it contains extracellular fluid.

Question 12

What are neurons in the chain of communication referred to as?

Answer 12

Presynaptic or Postsynaptic

Question 13

Myelin Sheath

Answer 13

A fatty material, made up of glial cells, that insulates the axon and allows for the rapid movement of electrical impulses along the axon.

Question 14

Nodes of Ranvier

Answer 14

Small gaps of exposed axon, between the segments of myelin sheath, where potentials are transmitted.

Question 15

Resting Membrane Potential

Answer 15

The electrical charge of a neuron when it is not active

Question 16

Polarization

Answer 16

• When the electrical charge inside a neuron is different from the electrical charge outside.
• A neuron at rest is polarized

Question 17

2 types of ions that contribute to a neuron’s resting membrane potential

Answer 17

Sodium Ions

Potassium Ions

Question 18

Permeability of cell membrane

Answer 18

Acts like a “bouncer” at a night club. Only allows certain types of ions to cross membrane. (More Potassium than Sodium is inside the neuron)

Question 19

Sodium-Potassium Pump

Answer 19

Works to increase potassium and decrease sodium inside the neuron.

Question 20

Action Potential

Answer 20

(Neural Firing) The neural impulse that passes along the axon and subsequently causes that release of chemicals from the terminal buttons.

• Neuron starts off slightly negative–>Fires & allows more positive ions in (depolarization)—> returns to slightly negative resting state (repolarization)

Question 21

2 types of signals that arrive at dendrites

Answer 21

Excitatory: depolarize the cell membrane (reduce polarization—>increasing the likelihood that a cell will fire)

Inhibitory: Hyper polarize the cell (increase polarization—>
decreasing the likelihood that the neuron will fire.

Question 22

Propagaion

Answer 22

The wave movement when the neuron fires and moves along the axon.

Question 23

All-or-none Principle

Answer 23

The principle where a neuron fires with the same potency each time, although frequency can vary. A neuron either fires or not. It can’t “partially” fire.

Question 24

Presynaptic Neuron

Answer 24

Sends the signal

Question 25

Postsynaptic Neuron

Answer 25

Receives the signal

Question 26

Neurotransmitters

Answer 26

Chemical substances that carry signals from one neuron to another.
After they spread across the synaptic cleft and attach themselves to receptors on the postsynaptic neuron.

Question 27

Receptors

Answer 27

In neurons, specialized protein molecules on the postsynaptic membrane.

Question 28

What are the three major events that terminate the neurotransmitter’s influence in the synaptic cleft?

Answer 28

Reuptake
Enzyme deactivation
Autoreception

Question 29

Reuptake

Answer 29

Occurs when the neurotransmitter is taken back into the presynaptic terminal buttons.

Question 30

Enzyme Deactivation

Answer 30

Occurs when an enzyme destroys the neurotransmitter in the synaptic cleft.

Question 31

Autoreceptors

Answer 31

Monitor how much neurotransmitter has been released into the synaptic cleft.

Question 32

Agonists

Answer 32

Drugs and toxins that enhance the actions of neurotransmitters.

Question 33

Antagonists

Answer 33

Drugs and toxins that inhibit the actions of neurotransmitters.

Question 34

9 Common Neurotransmitters

Answer 34

1. Acetylcholine: Motor control over muscles, learning, memory, sleeping, dreaming
2. Epinephrine (adrenaline): Energy
3. Norepinephrine: Arousal and vigilance/alertness
4. Serotonin: Emotional states and impulsiveness, dreaming
5. Dopamine: Reward and motivation, motor control over voluntary movement (eating, when hungry, drinking, sex)
6. GABA: Anxiety reduction, intoxication
7. Glutamate: Enhancement of action potentials, learning and memory
8. Endorphins: Pain reduction reward
9. Substance P: Pain perception, mood and anxiety

Question 35

Monoamnines (group)

Answer 35

Epinephrine, norepinephrine, serotonin, dopamine

Question 36

Parkinson’s Disease

Answer 36

Disorder marked by muscular rigidity, tremors, and difficulty initiating voluntary action.

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