I/E: Nervous Communication

Question 1

Stimulus

Answer 1

Any change in the internal or external environment.

Question 2

Receptors

Answer 2

Detect stimuli.

Can be proteins or cell surface membranes

Question 3

Effectors

Answer 3

Cells that bring about a response to a stimulus, to produce an effect.

Question 4

How do receptors communicate?

Answer 4

Using the nervous system or the hormonal system.

Sometimes both.

Question 5

What are the 3 main types of neurons?

Answer 5

Sensory

Motor

Relay

Question 6

Sensory neurons

Answer 6

Transmit electrical impulses from receptors to the CNS.

Question 7

Motor neurons

Answer 7

Transmit electrical impulses from the CNS to effectors.

Question 8

Relay neurons

Answer 8

Transmit electrical impulses between sensory neurons and motor neurons.

Question 9

What are electrical impulses also known as?

Answer 9

Nerve impulses or action potentials

Question 10

Describe a reflex arc:

Answer 10

Stimulus

Receptors

(Sensory neuron)

CNS (relay neuron)

(Motor neuron)

Response

Question 11

What are the two systems of the nervous system?

Answer 11

CNS - brain and spinal cord

Peripheral - neurons that connect to the rest of the body

Question 12

What are the two divisions of the peripheral nervous system?

Answer 12

Somatic = controls conscious activities

Autonomic = controls unconscious activities

Question 13

What are the two divisions of the autonomic nervous system?

Answer 13

Sympathetic = fight/flight response

Parasympathetic = rest + digest

Question 14

Reflex arc

Answer 14

Where the body responds to the stimulus without making a conscious decision to respond.

Question 15

Give an example of a simple reflex arc, eg. the hand-withdrawal response to heat:

Answer 15

• Thermoreceptors in skin detect stimulus
• Sensory neuron carries impulses to relay neuron
• Relay neuron connects to the motor neuron
• Motor neuron sends impulses to the effector (bicep muscles)
• Muscle contracts to withdraw hand and stop it being damaged

Question 16

What is possible if there is a relay neuron involved in the simple reflex arc?

Answer 16

It is possible to override the reflex, eg. the brain could tell your hand to withstand the heat.

Question 17

Give 3 words to describe the nervous system communication:

Answer 17

Localised

Short-lived

Rapid

Question 18

Why is the nervous system considered localised?

Answer 18

Neurotransmitters secrete the impulses directly onto target cells.

Question 19

Why is the nervous system considered short-lived?

Answer 19

Neurotransmitters are quickly removed once they have done their job.

Question 20

Why is the nervous system considered rapid?

Answer 20

Electrical impulses travel very fast which allows animals to react quickly to stimuli.