10.3 Reflex actions

Question 1

Why are reflexes important?

Answer 1

They enable you to avoid damage and danger because they happen very fast.
They control many vital bodily functions, such as breathing, without need for conscious thought.

Question 2

Why is it important that reflexes don’t go to the conscious areas of your brain?

Answer 2

This would slow process down, making it less effective at preventing damage. It would be very difficult to consciously control all bodily functions and still be able to do anything else.

Question 3

Explain why some actions such as breathing and swallowing are reflex actions, while others such as speaking and eating are under your conscious control

Answer 3

Reflex actions (e.g., breathing, swallowing) need to happen constantly and operate automatically, even when you are asleep, so cannot rely on conscious thought processes.
Speaking and eating require coordination of different areas of body so need to be under conscious control.

Question 4

Describe what happens when you step on a pin. Make sure you indicate when an electrical impulse or a chemical impulse is involved (6 marks)

Answer 4

stimulus (pinprick) → receptor → sensory neurone (electrical impulse) → synapse (chemical impulse) → relay neurone (electrical impulse) → synapse (chemical impulse) → motor neurone (electrical impulse) →
muscles in leg lift foot

Question 5

LEARN the reflex pathway off by heart

Answer 5

stimulus → receptor → sensory neurone → relay neurone → motor neurone (electrical impulse) → effector → response

Question 6

Reflex actions are ———— and ————– and do not involve the ________ parts of the brain

Answer 6

automatic
rapid
conscious

Question 7

Reflexes involve _________, ___________ and ____________

Answer 7

sensory
relay
motor neurones

Question 8

What are reflexes for?

Answer 8

help you to avoid danger or harm because they happen so fast.
take care of your basic body functions eg breathing, moving food

Question 9

What part of your brain do reflexes involve ?

Answer 9

unconscious