6

Question 1

What is a stimulus

Answer 1

A change in environment

Question 2

What is a receptor

Answer 2

Detects the change in environment, the stimulus

Question 3

What two parts does the nervous system make up

Answer 3

CNS- includes the brain and spinal cord
peripheral- all other peripheral nerves

Question 4

list the series of events that happens when a stimulus is detected

Answer 4

stimulus > receptor > coordinator > effector > response

Question 5

What is an action potential

Answer 5

When a nerves voltage increases beyond its set point/resting potential which is -70 mv
to form a nervous impulse

Question 6

what happens when a neurone reaches a voltage that is above its threshold

Answer 6

when nerve voltage increases beyond its threshold
when a voltage becomes more positive it becomes more permeable to sodium ions,

Question 7

why would a voltage become more positive

Answer 7

it becomes more permeable to sodium ions

Question 8

how does the action potential move

Answer 8

each action potential moves along the node of Ranvier

Question 9

from the cell body list the features of an axon

Answer 9

the cell body , dendrites , the nucleus , the axon , the myelin sheath , the node of Ranvier , Schwann’s cell , terminal part of axon

Question 10

describe the resting potential

Answer 10

resting potential is at -70 milli volts inside the axon and is maintained by potassium sodium pumps, and potassium channels, where one is permenantly open, potassium ions diffusing out maintains the resting potential

Question 11

What is the threshold

Answer 11

the minimum amount of voltage needed to trigger an action potential otherwise it would be a failed initiation

Question 12

What is depolarisation

Answer 12

a stimulus has been introduced this causes voltage gated sodium ion channels to open, becomes more positive as sodium ions diffuse into the axon
as the same time the potassium ions move out, this causes a slight increase in voltage

Question 13

what is repolarisation

Answer 13

after hitting 40 plus mV, voltage gated sodium ions close, potassium ion channels open , 2 open.
potassium moving out which causes a decrease in voltage, becomes more negative.

Question 14

what is the refectory period

Answer 14

it goes below the resting potential, reach -80 mV
Important because t ensures that the movement of the impulse is unidirectional, meaning that it will only travel forwards, not backwards.

Question 15

What are the three receptors we must know

Answer 15

• cones
  -Pacinian corpuscle
• rods

Question 16

What are nuerotransmitters

Answer 16

chemical messengers released from neurons

Question 17

What are simple reflexes

Question 18

Why are there failed initiations

Answer 18

there isnt a big enough stimulus to be detected, doesnt create a voltage increase past the threshold results in a failed initiation, the sodium voltage gated channels are too narrow

Question 19

are receptors specific

Question 20

What happens if there is a large enough stimulus

Question 21

what is the stimulus for a pacinian corpucsel

Question 22

where is the Pacinian corpuscle found

Question 23

explain how the Pacinian corpuscle works

Question 24

Why do organisms respond to the environment

Question 25

What is a tactic response

Question 26

what is a kinesis response

Question 27

Tropisms

Question 28

What is a reflex arc

Question 29

Nervous communication

Question 30

Auxin/ AII

Question 31

Photorecptors

Question 32

how to photoreceptors work

Question 33

Rods and cones

Question 34

Sensitivity of rods and cones

Question 35

Acuity of rods and cones

Question 36

STructure of the nervous system

Question 37

Heart rate

Question 38

Heart and rain