(nervous system) structure & function of neurons

Question 1

neurons

Answer 1

cells within nervous system that conduct nerve impulses

Question 2

3 types of neurons

Answer 2

• sensory
• relay
• motor

Question 3

components of a neuron

Answer 3

• nucleus
• dendrite
• cell body
• myelin sheath
• node of ranvier
• axon
• terminal buttons

Question 4

structure of cell body

Answer 4

includes nucleus which contains genetic material of cell

Question 5

where are dendrites found & function

Answer 5

found: branches off cell body on neurons

function: carry nerve impulses from neighbouring neurons towards cell body

Question 6

where’s the myelin sheath found & function

Answer 6

found: covers the axon & segmented by nodes of ranvier

function: protects axon & speeds up electrical transmission of impulse

Question 7

function of nodes of ranvier

Answer 7

speed up transmission of impulse by forcing it to ‘jump’ across gaps along axon

Question 8

function of axon

Answer 8

carries impulses away rom cell body down length of neuron

Question 9

what’s the axon

Answer 9

joins cell body & terminal buttons

Question 10

function of terminal buttons

Answer 10

communicate with next neuron in chain across gap (synapse)

Question 11

function of sensory neurons

Answer 11

• send info to brain regarding senses
• aka afferent neurons as carry info from PNS to CNS
• keep brain informed on internal/external environments
• only transmit messages

Question 12

structure of sensory neurons

Answer 12

• long dendrites & (relatively) short axons
• cell body usually to side of cell

Question 13

function of motor neurons

Answer 13

• carry signals from CNS towards organs, muscles & glands
• efferent neurons as carry info away from CNS towards PNS
• transmit & receive messages
• if connected to muscle = motor end plate

Question 14

structure of motor neurons

Answer 14

• short dendrites & (relatively) long axons

Question 15

function of relay neurons

Answer 15

• aka interneurons (take on role of sensory & motor neurons)
• connect sensory neurons to motor neurons
• based in CNS & carry signals/messages
• transmit/receive messages

Question 16

structure of relay neurons

Answer 16

• short axons & short dendrites

Question 17

location of motor neurons

Answer 17

• cell bodies may be in CNS
• long axons which form part of PNS

Question 18

location of relay neurons

Answer 18

• make up 97% of all neurons
• found in brain & visual system

Question 19

location of sensory neurons

Answer 19

• outside of CNS
• in PNS in clusters = ganglia

Question 20

describe process of electrical transmission (firing of a neuron)

Answer 20

1. in resting state, inside of cell is negatively charged compared to outside
2. when activated by a stimulus, the inside of the cell becomes positively charged for a split second causing an action potential to occur
3. creates electrical impulse which travels down axon towards end of neuron