Synapses And Reflexes

Question 1

what is a synapse

Answer 1

the connection between two neurones

Question 2

what are nerve signals transferred by

Answer 2

• chemicals called neurotransmitters

- which diffuse across the gap

Question 3

how do signals travel from one neurone to the next

Answer 3

the neurotransmitters set off new electrical signal in the next neurone

Question 4

although the transmission of nervous impulses are fast, what slows them down

Answer 4

• the diffusion of neurotransmitters across synapses

- this takes time

Question 5

what are reflexes

Answer 5

automatic and rapid responses to stimuli

Question 6

why do we have reflexes

Answer 6

to reduce our chances of getting injured

Question 7

what is the passage of information in a reflex, from the receptor to the effector, called

Answer 7

a reflex arc

Question 8

where do neurones in reflex arcs go through

Answer 8

• the spinal cord

- or through an unconscious part of the brain

Question 9

what is an examplle of a stimulus

Answer 9

a bee sting or touching a hot pan

Question 10

what is the first thing that happens when you have touched a hot pan

Answer 10

the stimulus, heat, is detected by pain receptors

Question 11

what is the response to the heat being detected by the receptors

Answer 11

impulses are sent along sensory neurones to a relay neurone in the central nervous system

Question 12

what happens when impulses reach a synapse between the sensory neurone and a relay neurone and what does this cause

Answer 12

• they trigger neurotransmitters to be released

- these cause impulses to be sent along the relay neurone

Question 13

what happens when impulses reach a synapse between the sensory neurone and a motor neurone and what does this cause1

Answer 13

• it triggers neurotransmitters to be released

- which cause impulses to be sent along the motor neurone

Question 14

where do the impulses travelling through the motor neurone go to

Answer 14

• the effector

- this could be a muscle or a gland for example

Question 15

what happens when the impulses reach the muscle they wee travelling to

Answer 15

• it causes the muscle to contract

- which moves your hand away from the hot pan

Question 16

why are reflexes quicker than normal responses and why are they advantageous

Answer 16

• you dont have to spend time thinking about the response

- meaning you can act quicker and get out of danger or injury with the least amount of damage done

Question 17

what is the whole process of a reflex is a bee were to sting your finger

Answer 17

• the bee stings your finger
• stimulates the pain receptors
• impulses travel along the sensory neurone
• impulses are passed along to the relay neurone in the CNS vis synapses
• impulses travel along a motor neurone via synapses
• when impulses reach the muscle it causes it to contract

Question 18

why do we have reflexes to protect the eye

Answer 18

because very bright light can damage the eye

Question 19

what do light receptors in the eye do

Answer 19

• they detect very bright light

- and send a message along the sensory neurone to the brain

Question 20

what happns after the impulses have reached the brain

Answer 20

• they travel along relay neurones to a motor neurone
• which tells circular muscles in the iris ( the coloured part)
• to contract, making the pupil smaller