Reflex Actions

Question 1

Reflexes are Automatic and Rapid, they don’t Involve the Conscious Part of the ________.

Answer 1

Brain.

Question 2

Simple Reflex Actions Often Involve which Three Types of Neurone?

Answer 2

• Sensory Neurone.
• Motor Neurone.
• Relay Neurone.

Question 3

What do Relay Neurones do?

Answer 3

These Connect a Sensory Neurone and a Motor Neurone, and are Found in the CNS.

Question 4

Explain the Reflex Arc?

Answer 4

• An Electrical Impulse Passes From the Receptor Along the Sensory Neurone to the CNS.
• It then Passes Along a Relay Neurone and Back Along the Motor Neurone.
• The Impulse Arrives At The Effector Organ which will be a Muscle or Gland.

Question 5

The Electrical Impulses in a Reflex Arc Bypass the ____________ Areas of the Brain.

Answer 5

Conscious.

Question 6

Neurones aren’t Joined Up Directly. What are the Junctions Between them Called which Form Physical Gaps Between the Neurones?

Answer 6

Synapses.

Question 7

Electrical Impulses Travelling Along Neurones have to Cross _______________.

Answer 7

Synapses.

Question 8

Diffusion of the Chemical Across the ____________ is Slower than the Electrical Impulse in the Neurones.

Answer 8

Synapse.

Question 9

Stages in the Reflex Arc of what Happens when you Touch a Hot Object?

Answer 9

• A Receptor in the Skin is Stimulated. An Electrical Impulse From a Receptor Passes Along a Sensory Neurone to the CNS.
• When an Impulse From the Sensory Neurone Arrives at the Synapse with a Relay Neurone, a Chemical is Released. The Chemical Diffuses Across the Synapse to the Relay Neurone where it Sets Off a New Electrical Impulse that Travels Along the Relay Neurone.
• When the Impulse Reaches the Synapse Between the Relay and Motor Neurone Returning to the Arm, Another Chemical is Released. This Chemical Diffuses Across the Synapse and Starts a New Electrical Impulse Travelling Down the Motor Neurone to the Effector.
• When the Impulse Reaches the Effector Organ, it is Stimulated to Respond.

Question 10

Reflex Pathway (Summed Up)?

Answer 10

Stimulus –> Receptor –> Sensory Neurone –> Relay Neurone –> Motor Neurone –> Effector –> Response.

Question 11

In a Reflex Action, the Coordinator is a _________ Neurone Either in the Spinal Cord or the Unconscious Area of the Brain.

Answer 11

Relay.