Section 6: Coordination and Response

Question 1

The Nervous System & Responding to Stimuli

How do animals increase their chances of survival?

Answer 1

By responding to changes in their external and internal environment.

Question 2

The Nervous System & Responding to Stimuli

What is the importance of animals responding to their internal environment?

Answer 2

To ensure that conditions are right for their metabolism (all chemical reactions that occur in them)

Question 3

The Nervous System & Responding to Stimuli

Stimulus

Answer 3

A change in the external environment.

Question 4

The Nervous System & Responding to Stimuli

Receptor

Answer 4

A group of cells in sense organs that detect external stimuli.

E.g Rod & cone cells in eye detect changes in light.

Question 5

The Nervous System & Responding to Stimuli

Effector

Answer 5

Group of cells that produce a response to stimuli.

E.g
Muscle cells - contract
cells in glands (e.g pancreas) - secrete hormones

Question 6

The Nervous System & Responding to Stimuli

CNS? What is its job?

Answer 6

“Central Nervous System”
It coordinates a response.

Coordinated responses always need a stimulus, receptor and effector.

Question 7

The Nervous System & Responding to Stimuli

What does CNS consist of?

Answer 7

Brain and spinal cord only

Question 8

The Nervous System & Responding to Stimuli

How does the nervous system send rapid responses?

Answer 8

Neurones transmit information using high speed electrical impulses

Question 9

The Nervous System & Responding to Stimuli

Synapses?

Answer 9

Connection between two neurones

Question 10

The Nervous System & Responding to Stimuli

Explain how nerve signals are transferred in synapses.

Answer 10

• Nerve signal is transferred by chemicals called neurotransmitters
• These diffuse (move) across the gap
• The neurotransmitters send a new electrical signal into the next neurone

Question 11

Reflexes

Reflexes? What do they do?

Answer 11

• They are automatic responses to stimuli that do not require conscious intervention.
• They can reduce the chances of being injured

Question 12

Reflexes

Reflex arc?

Answer 12

Route taken by the information in a reflex (from receptor to effector)

Question 13

Reflexes

Examples of reflexes?

Answer 13

• bright light shining in eyes, pupils get smaller so less light gets into the eyes - preventing damage
• When you get shock, body releases hormone adrenaline automatically

Question 14

Reflexes

Explain the reflex arc diagram

Answer 14

Stimulus - Receptor - Sensory neurone - CNS - Motor neurone - Effector - Response