Neurons

Question 1

What does the dendrite do?

Answer 1

Brings the input to the cell.

Question 2

What does the dendrite look like?

Answer 2

Like a tree’s branches or roots

Question 3

What is the main role of the nervous system?

Answer 3

Communication—bringing information in from the outside world to the nervous system and brain to be analyzed and sending information from the brain and nervous system out to the body to interact with the outside world.

Question 4

What does the axon look like?

Answer 4

The axon is of uniform thickness or diameter and can extend for as far as several feet in mammals, half the length of your entire body! Some axons branch, and these branches may extend to other regions of the brain or body.

Question 5

What do some dendrites have?

Answer 5

Some have spines or small protrusions of the neuronal membrane the typically make contact with one other neuron.

Question 6

What is the axon used for?

Answer 6

Transmitting electrical signals or releasing packets of chemical transmitters.

Question 7

What does the myelin do?

Answer 7

Insulates the axons. Speeds up the conduction of the neuron’s electrical signals that travel down the axon.

Question 8

What is the myelin?

Answer 8

A fatty substance made glial cells.

Question 9

What does the axon do?

Answer 9

Transmits output signals from the neuron

Question 10

What are Nodes of Ranvier?

Answer 10

Small gaps in the myelin.

Question 11

What do the Nodes of Ranvier do?

Answer 11

They allow the axon inside to gain access to the fluid outside the cell, which is important for sending electrical signals.

Question 12

Where is the nucleus found?

Answer 12

The cell body, or soma.

Question 13

Where does the axon begin and end?

Answer 13

Axons begin at the soma, at a section of the axon called the axon hillock, and end in slightly wider sections called the axon terminals.

Question 14

What happens at the axon terminal?

Answer 14

The neuron will release its signal in the form of a neurotransmitter, passing the information to the next neuron. Most of the time the signal is received at one of that other neurons dendritic spines.

Question 15

What is a synapse?

Answer 15

A synapse is the transfer of information from neuron to another.

Question 16

What is the synaptic cleft?

Answer 16

It’s the space between where two neurons connect.

Question 17

What is a presynaptic neuron?

Answer 17

The first neuron in a synapse.

Question 18

What is a postsynaptic neuron?

Answer 18

The second neuron receiving the signal.

Question 19

The axon terminal of the presynaptic neuron is usually filled with what?

Answer 19

Spherical packets (or vesicles) of signaling chemicals called neurotransmitters.

Question 20

Where are neurotransmitters produced?

Answer 20

Neurotransmitters are usually produced in the soma and are sent down the axon to the terminal.

Question 21

How do neurotransmitters travel?

Answer 21

At the proper time, the neurotransmitters are then released to float across the synaptic cleft and bind to specialized receptors that receive the neurotransmitter signal on the postsynaptic neuron.This method of signaling across the synaptic cleft is highly customizable and plays a large role in neural communication.

Question 22

What does a neuron’s shape depend on?

Answer 22

Their job in the nervous system.

Question 23

What are the three types of neurons?

Answer 23

Motor neurons, sensory neurons, and interneurons.

Question 24

What do motor neurons do and how do they look?

Answer 24

Motor neurons that bring movement commands to the muscles tend to have a soma at one end of the cell surrounded by a small set of dendrites and then a very large, long axon going out to the muscle.

Question 25

What do sensory neurons do and how do they look?

Answer 25

Sensory neurons vary widely and are different from motor neurons,as their role is to bring sensory input from the body to the brain. Some sensory neurons have dendrites at both ends connected by a long axon with a cell body on a branch in the middle.

Question 26

What do interneurons look like and how do they work?

Answer 26

They work to connect other neurons within the nervous system and are often quite small without long axons or large complex dendritic arbors

Question 27

The central nervous system can generally be divided up into which two types of tissue?

Answer 27

Grey Matter and White Matter

Question 28

What is grey matter made of?

Answer 28

This is made of the cell bodies and dendritic arbors of neurons.

Question 29

What is white matter made of?

Answer 29

This is made of the myelinated axons of the neurons.

Question 30

When the brain is opened, what is the color difference between the axons and the cell bodies and dendrites?

Answer 30

The axons are lighter in color while the cell bodies and dendrites are tan or darker grey. tan (depending on if the brain has been preserved or is fresh)

Question 31

Where are the grey matter and white matter located?

Answer 31

In the brain, the grey matter is located mostly on the outside with the white matter tucked inside.

Question 32

How is it different in the spinal cord?

Answer 32

The white matter axons are on the outside, and it is the cell bodies that are tucked inside the structure.