Biopsychology: topic 2 ‘structure and function of sensory, relay and motor neurons’

Question 1

what are the three types of neurons?

Answer 1

• sensory, relay, and motor neurons

Question 2

what percentage of neurons are located in the brain?

Answer 2

80%

Question 3

how many neurons are in the human nervous system?

Answer 3

• 100 billion

Question 4

what is the primary means of communication in the nervous system?

Answer 4

• transmission of signals electrically and chemically

Question 5

what is the basic structure shared by all neurons?

Answer 5

• vary in size from less than a millimetre up to a metre long depending on their function
• cell body (soma), dendrites, axon

Question 6

what does the cell body (soma) of a neuron contain?

Answer 6

• nucleus

Question 7

what are dendrites responsible for?

Answer 7

• receiving signals from other neurons or sensory receptors

Question 8

what is the function of the axon?

Answer 8

• carries impulses away from the cell body

Question 9

what covers the axon and speeds up electrical transmission?

Answer 9

• myelin sheath

Question 10

what are the gaps in the myelin sheath called?

Answer 10

• nodes of ranvier

Question 11

what effect do the nodes of ranvier have on impulse transmission?

Answer 11

• speed up the transmission by forcing it to ‘jump’ across the gaps

Question 12

what are terminal buttons?

Answer 12

• structures at the end of the axon that communicate with the next neuron

Question 13

what is the gap between neurons called?

Answer 13

• synapse

Question 14

fill in the blank: the axon carries impulses away from the cell body down the length of the _______

Answer 14

• neuron

Question 15

true or false: the myelin sheath is continuous along the axon

Answer 15

false

Question 16

what is the role of the myelin sheath?

Answer 16

• protects the axon and speeds up electrical transmission

Question 17

what type of neuron carries messages from the PNS to the CNS?

Answer 17

• sensory neurons

Question 18

where are sensory neurons found in the body?

Answer 18

• eyes, ears, tongue, skin

Question 19

what do sensory neurons process information from?

Answer 19

• sensory neurons tell the rest of the brain about the external and internal environment by processing information taken from one of the five senses

Question 20

true or false: all sensory information travels to the brain

Answer 20

• false, some neurons terminate in the spinal cord

Question 21

what allows reflex actions to occur quickly?

Answer 21

some neurons terminating in the spinal cord

Question 22

what is the structure of sensory neurons?

Answer 22

• long dendrites and short axons

Question 23

what do relay neurons connect?

Answer 23

• sensory neurons to motor or other relay neurons

Question 24

what is the primary role of relay neurons?

Answer 24

• carry messages from one part of the CNS to another

Question 25

what is the structure of relay neurons?

Answer 25

- short dendrites and short axons

Question 26

what type of neurons carry messages from the CNS to directly or indirectly control muscles?

Answer 26

- motor neurons

Question 27

what triggers muscle movement when motor neurons are stimulated?

Answer 27

- release of neurotransmitters (chemical messengers) that bind to receptors on the muscle and trigger a response which leads to muscle movement

Question 28

what happens to muscles during relaxation?

Answer 28

- inhibition of the motor neuron

Question 29

what is the structure of motor neurons?

Answer 29

- short dendrites and long axons