The nervous system - neurons - ch 12

Question 1

Describe neurons?

Answer 1

specialised nerve cells

Question 2

What are neurons responsible for?

Answer 2

1. commicating information in both chemical and electrical forms

Question 3

Do neurons vary in size, shape and characteristics depending on their function and role?

Answer 3

yes

Question 4

Name the three parts neurons have?

Answer 4

1. cell bodies
2. dendrite
3. axon or nerve fibre

Question 5

What do cell bodies contain?

Answer 5

nucleus

Question 6

Describe dendrites and their role?

Answer 6

1. hair-like structures that surround the cell body and which manage and direct incoming signals

Question 7

What is the role of the axon and nerve fibre?

Answer 7

they guide the outgoing signals from the neuron.

Question 8

What are axons covered in?

Answer 8

fatty sheath called myelin which acts to insulate the axon and facilitates the transmission of impulses.

Question 9

How do neurons communicate?

Answer 9

by transmitting information both within the neuron and from one neuron to the next.

Question 10

Where do neurons dendrites receive information from?

Answer 10

sensory receptors or other neurons

Question 11

Where is the information from the the dendrites transferred to?

Answer 11

the cell body and then travels down the length of the axon in the form of an electrical signal known as an action potential. The point at which the message passes between two nerve cells is called a synapse.

Question 12

Describe a synapse?

Answer 12

a small gap across which chemical neurotransmitters diffuse or electrical impulses connect to pass instructions to the dendrites of other neurons or to activate specialised sites called receptors on a target cell.

Question 13

Is the target cell a specialised part of a muscle cell or a gland?

Answer 13

Yes

Question 14

Can the electrical signal on occassion instantaneously connect across the space between the neurons and continue along its path?

Answer 14

Yes

Question 15

What is the role of the chemical messenger (neurotransmitter)?

Answer 15

(neurotransmitter) diffuses across the synapse to reach the receptor sites of other neurons in a process that is slower than the electrical signal

Question 16

Around how many neurotransmitter types are there?

Answer 16

around one hundred

Question 17

Name 3 neurotransmitters?

Answer 17

1. acetylcholine
2. endorphins
3. dopamine

Question 18

What is the role of acetylcholine (neurotransmitter)?

Answer 18

it works with memory, muscle contractions and learning.

Question 19

If a lack of acetylcholine in the brain is correlated, what is the name of the diagnosis?

Answer 19

Alzheimers disease

Question 20

What is the role of endorphins?

Answer 20

They are connected with emotions and the perception of pain, fear and trauma. They reduce pain.

Question 21

What is the role of dopamine?

Answer 21

This neurotransmitter relates to thought and feelings of pleasure

Question 22

What is a deficit in dopamine related to?

Answer 22

Parkinson’s disease, excessive amounts are thought to be linked to schizophrenia

Question 23

How classes of neurons are there?

Answer 23

three

Question 24

Name the three classes of neurons?

Answer 24

1. sensory neurons
2. interneurons
3. motor neurons

Question 25

What is the role of a sensory neuron?

Answer 25

to receive information from the body's internal and external sensory receptors and convert the messages received into electrical impulses for transfer to the central nervous system.

Question 26

What is the role of the external sensory?

Answer 26

the external sensory receptors react as we look, listen, smell, taste, touch and feel

Question 27

What is the role of the internal sensory?

Answer 27

the internal sensory receptors report on the condition of the internal organs, such as state of the bladder, the digestive system, blood pressure and osmolality.

Question 28

Are there other receptors that respond to the positio of the body and its movements?

Answer 28

yes

Question 29

What is the role of the interneurons?

Answer 29

to transfer messages and impulses to and from the sensory neurons and to and from other interneurons. Branching from the end of the interneurons are dendrites, which receive information by means of signals sent from the axon of another neuron.

Question 30

true or false? Can interneurons only transmit information in one direction?

Answer 30

Yes

Question 31

What is the role of motor neurons?

Answer 31

to send messages from the central nervous system to the muscles and glands to initiate an action or carry out a response.

Question 32

What are most motor neurons stimulated by?

Answer 32

interneuronss, but some receive direct stimulation from sensory neurons.