Biology 5.1.2

Question 1

What is an ‘Involuntary Response’?

Answer 1

A Response that does not involve the Conscious part of the Brain as the Coordinator of the Reaction.

Question 2

A ___ Neurone sends Electrical Impulses to the Coordinator. (After the Stimulus).

Answer 2

Sensory.

Question 3

From the Coordinator, an Electrical Impulse is passed to a ___ Neurone.

Answer 3

Relay.

Question 4

A Relay Neurone ___ with a ___ Neurone.

Answer 4

Synapses, Motor.

Question 5

A ___ Neurone carries an Impulse to the Effector.

Answer 5

Motor.

Question 6

What are the 3 main types of Neurone in a Reflex Arc, and what do they do? (3)

Answer 6

-Sensory Neurone: Carries Impulses from Sense Organs to the CNS.

-Relay Neurone: Found inside the CNS, & Connect Sensory & Motor Neurones.

-Motor Neurone: Carries Impulses from the CNS to Effectors.

Question 7

What do Sensory Neurones have Branching off the Middle of the Axon?

Answer 7

A Cell Body.

Question 8

Sensory Neurones are ___.

Answer 8

Long.

Question 9

Relay Neurones are ___.

Answer 9

Short.

Question 10

What do Relay Neurons have at one end?

Answer 10

A Small Cell Body with many Dendrites Branching off it.

Question 11

Motor Neurones are ___.

Answer 11

Long.

Question 12

What do Motor Neurones have at one end?

Answer 12

A Large Cells Body with Long Dendrites Branching off it.

Question 13

Neurones never touch each other. They are Separated by junctions (gaps) called…

Answer 13

Synapses.

Question 14

Electrical Impulses cannot cross over ___.

Answer 14

Synapses.

Question 15

Where are there Synapses located in a Reflex Arc? (2)

Answer 15

-Between the Sensory & Relay Neurones.

-Between the Relay & Motor Neurones.

Question 16

Chemicals called ___ are Released into the ___, and Diffuse across it.

Answer 16

Neurotransmitters, Synapses.

Question 17

How do Electrical Impulses cross over Synapses?

Answer 17

Via Neurotransmitters. They Stimulate the second Neurone to Generate an Electrical Impulse that travels down the second Axon.

Question 18

Why don’t Relay Neurons have Myelin Sheaths?

Answer 18

Because they don’t carry Electrical Impulses over Long enough Distances to warrant the need for one.

Question 19

Explain the Reflex Arc that Occurs when you touch something Hot? (6)

Answer 19

-Stimulus (heat) Triggers Receptors in the Skin of your Hand.

-Receptor Sends Electrical Impulse to CNS Via Sensory Neurone.

-Sensory Neurone reaches a Synapse & Needs to Pass it. Neurotransmitter Chemical is Released, & it Passes the Electrical Impulse to a Relay Neurone.

-Relay Neurone Carries Electrical Impulse to another Synapse. Once again, a Chemical is Released, & it Passes the Electrical Impulse to a Motor Neurone.

-Motor Neurone Carries the Electrical Impulse to the Effector, which in this case, is an Arm Muscle.

-The Arm Muscle Contracts, & Pulls the Hand Away from the Hot Object. This is Called the Response.