Synapses and reflexes and Reaction time practical.

Question 1

What is the Synapses and what is its function?

Answer 1

The connection between two neurons is called a synapse. The nerve signal is transferred by chemical which diffuse across the gap. These chemicals then set off a new electrical signal in the next neurone.

Question 2

What are reflexes?

Answer 2

They are rapid, automatic responses to certain stimuli that don’t involve the conscious part.

Question 3

How do they prevent injury?

Answer 3

If a bright light is shone into the eye, the pupil gets smaller so less light gets into the eye, reducing the chances of being injured.

Question 4

What is the passage of information in a reflex from the receptor to effector called ?

Answer 4

The reflex arc

Question 5

How does the Reflex arc work?

Answer 5

1. The neurons in the reflex arc go through the spinal cord or through an unconscious part of the brain
2. When a stimulus (painful bee sting) is detected by receptors, impulses are sent along a sensory neurone to a relay neurone in the CNS.
3. When the impulses reach the synapse between the sensory neurone and the relay neurone, they trigger chemicals to be released, these chemicals cause impulses to be sent along the relay neurone.
4. When the impulses reach the synapse between the relay neurone and motor neurone, the same thing happens. Chemicals are released and cause impulses to be sent along the motor neurone
5. The impulses then travel along the motor neurone to the effector.
6. The muscle then contracts and moves your hand away from the bee.

Question 6

What is reaction time?

Answer 6

Reaction time is the time tacked for an individual to respond to a stimulus. It is affected by factors such as age, gender or drugs.

Question 7

Caffeine is a drug that can speed up a persons reaction time, the effect on reaction time can be measured like this … ( testing reaction time practical)

Answer 7

1. The person being tested should sit with their arm resting on the edge of a table - to stop their arm moving up and down.
2. Hold a ruler vertically between their thumb and index and index finger. Then let go with giving any warning.
3. The person being tested should try catch the ruler as quickly as they can.
4. Reaction time is measured by the number in the ruler where it is caught. The higher the number- the slower the reaction time.
5. Repeat the test several times the calculate the mean distance the ruler fell.
6. The persone being tested should then have a caffeinated drink. After ten minuetes, repeat steps 1 to 5.
7. You need control variables to make sure that the test if fair. For example, you should use the same person and the same hand to do the caffiene tested on. The ruler should also be dropped from the same height as before.
8. Too much caffeine can have unpleasant side effects, so the person being tested should avoid caffeine for the rest of the day.

Question 8

How can reaction time be measured by using a computer?

Answer 8

1. Simple computer tests can be used to measure reaction time. For example, the person being tested have to click the mouse as soon as they see a stimulus in the screen.
2. Computers can give a more precise reaction time because they remove the possibility of human error from the measurements.
3. As the computer can record the reaction time in milliseconds, it can also give more accurate measurements.
4. Using a computer can also remove the possibility that the person can predict when to respond - using the ruler test , the catcher may learn to anticipate the drop by reading the tester’s body language.