synapses and reflexes

Question 1

Define synapses

Answer 1

Gap, connection between two neurons, Chemicals - neurotransmitters - diffuse out one into another which makes it possible to electrical impulses to continue

Question 2

What’s lots of neurons called?

Answer 2

nerve

Question 3

functions of parts of neurone 1

Answer 3

nucleus = which contains genetic info like DNA which controls the cells activities
Cell membrane = controls substances in and out of cell
Cytoplasm = jelly like material where chemical reactions occur
Dendrites = carry electrical impulses away from receptor

Question 4

functions of parts of neurone 2

Answer 4

Axon = long projection of the neuron cell that takes electrical impulses away from cell body
Nerve endings = can pass electrical impulses to other neurones
Myelin sheath = speeds up and insulates transmission

Question 5

What are reflexes?

Answer 5

They are rapid automatic responses to certain stimuli that don’t involve the conscious part of the brain - they can reduce the chances of being injured

Question 6

example of reflex

Answer 6

someone shines a bright light in your eye, your pupils automatically get smaller to let less light in to prevent damage

Question 7

What’s the passage of information in a reflex called?

Answer 7

• The reflex arc

Question 8

Explain the reflex arc in detail 1

Answer 8

• The neurones in the reflex arc go through the spinal cord or the unconscious part of the brain
• When a stimulus is being detected by the receptors, impulses then travel along sensory neurone to relay neurone in the CNS

Question 9

Explain the reflex arc in detail 2

Answer 9

• When the impulses reach a synapses between the sensory neurone and relay neurone, they trigger chemicals to be released
  -These chemicals cause impulses to be sent along the relay neurone
• when the impulses reach a synapses between the relay and motor neurone, chemicals are released and cause impulses to be sent along the motor neurones

Question 10

Explain the reflex arc in detail 3

Answer 10

• The impulses then travel along the motor neurone to the effector which organises response
• response is automatic and quick

Question 11

Define reaction time

Answer 11

Time is takes to respond to stimulus - often less than a second
- Affected by age, gender or drugs

Question 12

Steps of reaction time practical (1)

Answer 12

Caffeine is a drug which speeds up persons reaction time, the effect of reaction time of caffeine can be measured
- The person being tested should sit with their arm resting on the edge of the table
- Person A holds a ruler vertically between thumb and forefinger, making sure 0 end of ruler is level with thumb and finger, then let go without warning

Question 13

Steps of reaction time practical (2)

Answer 13

• Person B (one tested) should try to catch it as quick as they can as soon as the ruler drops
• The reaction time is measured by the number the ruler is caught, the number should be read by top of thumb, further down the number = slower the reaction time

Question 14

Steps of reaction time practical (3)

Answer 14

• Repeat several times and calculate mean distance ruler fell
• Person being tested with caffeine drink should wait around 10 mins and repeat the test 1-5

Question 15

What must be controlled?

Answer 15

• variables such as same person and hand catching ruler, same height, amount of caffeine , no caffeine in beginning

Question 16

What could cause harm?

Answer 16

• too much caffeine can cause unpleasant side effects so person being tested should avoid drinking any more caffeine for the rest of the day

Question 17

How can reaction time be measured?

Answer 17

• simple computer test can be used
  example, clicking mouse every time a person spots a stimulus on screen
• Computers provide more of a precise reaction timer and remove possibility of human error from the measurement

Question 18

Why is using a – more precise?

Answer 18

• computer
  It records it in milliseconds = MORE ACCURATE MEASUREMENT
  Using a computer also remove the possibility that the person can predict when to respond (body language)