14. Coordination and control (mammals)

Question 1

Which organ produces a hormone?

Answer 1

OVARY

Question 2

Which part of the human eye is sensitive to light?

Answer 2

RETINA

Question 3

What happens when a person looks at an object far away from their eye?

Answer 3

• Suspensory ligaments tighten
• Lens becomes thinner

Question 4

What happens when a ciliary muscle relaxes

Answer 4

• The lens will decrease its curvature

Question 5

How do the muscles make the pupil smaller?

Answer 5

• Circular muscles contract
• Radial muscles relax

Question 6

What would be the pupil size and lens shape of a person reading a mobile phone text message in a brightly lit room?

Answer 6

• The pupil size would be small and the lens shape would be fat

Question 7

What happens when a ciliary muscle contracts?

Answer 7

• Reduces the pull on the lens, increasing its curvature

Question 8

State two ways in which a voluntary action differs from an involuntary action.

Answer 8

• Takes more time
• No automatic

Question 9

Explain how the parts of the reflex respond to the detection of heat.

Answer 9

• When a person touches a hot object. Electrical impulses are generated and transferred(by receptor) to the sensory neuron.
• Sensory neuron carries the impulses along itself to the central nervous system
• Electrical impulses are then transferred along the synapse to relay neuron
• Impulses travel along the relay neuron to the motor neuron again through a synapse
• Motor neuron then carries the impulses to the effector(muscle) and contracts.

Question 10

What is meant by the term involuntary action

Answer 10

• It is a response without the use of the brain and is an automatic response

Question 11

Describe the advantages of simple reflexes

Answer 11

• Fast
• Automatic

Question 12

Describe 3 ways this adrenaline increase prepares the body for action.

Answer 12

• Heart beats faster
• Increased rate of breathing
• Heightened sensitivity

Question 13

Describe a simple reflex arc

Answer 13

• Stimulus detected by receptor
• Receptor sends electrical impulses to the sensory neuron
• Sensory neuron passes impulses to relay
• Relay passes impulses to the motor
• Motor passes to the effector

Question 14

Describe how impulses pass from one neuron to another across a synapse

Answer 14

• Neurotransmitters released from vesicles into the synaptic gap
• Neurotransmitters move by diffusion
• The neurotransmitter binds with the receptor which is on the other side of the synapse causing the impulse to continue

Question 15

Outline the pathway in a reflex arc in response to shining a bright light into the eye

Answer 15

• The stimulus (light) is detected by the retina (receptor) and electrical impulses are generated by the receptor.
• Sensory neuron -> Relay neuron -> Motor neurone
• There are synapses between the neurons
• Circular muscles contract / Respond

Question 16

Describe and explain how drug X affects the function of the relay neuron.

Answer 16

• Drug X blocks D (receptor molecules)
• Neurotransmitters are not able to bind to D (receptor molecules)
• Drug X’s shape is complimentary to the shape of the receptor

Question 17

Name the part of the eye that alters the direction of light rays

Answer 17

Cornea

Question 18

Name part of the eye where the light rays form an image

Answer 18

Retina