Section 6 - Reflexes Flashcards Preview

Edexcel GCSE Biology > Section 6 - Reflexes > Flashcards

Flashcards in Section 6 - Reflexes Deck (24)
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1
Q

What is a stimulus (1)

A
  • Any change in the internal or external enviornment
2
Q

How does responding to their enviornment help organisms survive (4)

A
  • Animals increase their chances of survival by responding to changes in their external enviornment
  • Also respond to changes in their internal enviornment, to make sure the conditions are right for their metabolism
  • Plants also increase their chances of survival by responding to changes in their enviornment
  • Any change in the internal/external enviornment is called a stimulus
3
Q

Where are receptors found and what is their job (2)

A
  • Sense organs (eyes ears etc)
  • Detect external stimuli
4
Q

What are effectors and give two examples of what they do (3)

A
  • Cells that bring about a response to stimuli
  • Muscle cells contract
  • Glands secrete hormones
5
Q

What are the 3 types of neurone (3)

A
  • Sensory
  • Motor
  • Relay
6
Q

What does the Central nervous system consist of (2)

A
  • Brain
  • Spinal cord
7
Q

When receptors detect a stimulus, what do they do? (1)

A
  • Send electrical impulses along sensory neurones to the CNS
8
Q

What is the CNS’s role in a response (3)

A
  • CNS sends electrical impulses to an effector
  • Along a motor neurone
  • Effector then responds accordingly
9
Q

Coordinated responses always need a …….. , a ……….. and an ……….. (3)

A
  • Stimulus
  • Receptor
  • Effector
10
Q

When someone shines a bight light in your eyes, what happens and why (3)

A
  • Pupils automatically get smaller
  • So less light gets into the eye
  • Stops it getting damaged
11
Q

What is the main job of the CNS (1)

A
  • Coordinate the response
12
Q

What are reflexes (1)

A
  • Automatic responses to certain stimuli
13
Q

After a cupcake candle burns your finger, what happens (1)

A
  • Stimulaton of the pain receptor
14
Q

After your pain receptors are stimulated, what happens (1)

A
  • Impulses travel along sensory neurones
15
Q

After impulses travel along the sensory neurone, what happens (2)

A
  • Impulses are passed along a relay neurone
  • Via a synapse
16
Q

What travels along sensory neurones (1)

A

Impulses

17
Q

After impulses are passed along a relay neurone, via a synapse, what happens (2)

A
  • Impulses travel along a motor neurone
  • Via a synapse
18
Q

After impulses travel along a motor neurone via a synapse, what happens (1)

A
  • When impulses reach muscle, it contracts
19
Q

What order do impulses travel along receptors (3)

A
  • Sensory
  • Relay
  • Motor
20
Q

When a stimulus is detected by receptors, an impulse is sent along a ……. neurone to the ……

A
  • Sensory
  • CNS
21
Q

What is the fibre called which carries impulses to the effector (1)

A
  • Axon
22
Q

What is the axon covered in (1)

A
  • Mylelin sheath
23
Q

What are the five steps in the reflex arc (5)

A
24
Q

What are two purposes of the myelin sheath (2)

A
  • Prevents short circuits with other axons
  • Speeds up conduction of impulses