Topic 09,10- Coordination And Response & Homeostasis

Question 1

Differences between Voluntary actions and involuntary actions

Answer 1

Voluntary: Controllable, Brain—>Spinal cord—>motor neurone—>muscles
Involuntary: Automatic, Receptor—>Sensory neurone—>Relay neurone—>Motor neurone—>Effector

Question 2

How do nerve impulses travel through the nervous system?

Answer 2

1. A nerve impulse arrives at the terminal end of an axon
2. With ATP provided by mitochondria, the nerve impulse stimulates the terminal end of the axon to release neurotransmitters stored in vesicles
   3.The neurotransmitters diffuse across the synapse
3. The neurotransmitters stimulate the dendrite of the next neurone to generate a
   Nerve impulse.

Question 3

Effect of drugs on synapses

Answer 3

Heroin and neurotransmitters have a very similar shape, they compete for receptors to bind on.

Question 4

Rods

Answer 4

• Work well in dark conditions
• Responsible for black and white vision
• Distributed throughout the retina, nine at the fovea and blind spot

Question 5

Cones

Answer 5

• Responsible for coloured vision
• Three types: Red, blue and green
• Work well in bright conditions
• Concentrated at fovea, only a few at the periphery of retina

Question 6

What is homeostasis?

Answer 6

The control of internal conditions within set limits

Question 7

Negative feedback

Answer 7

• A change from normal level stimulate negative response that cancel out the change
• The sensor detects the effect and instructs the effector to produce the opposite effect

Question 8

Symptoms of type 1 diabetes

Answer 8

• Excessive thirst, hunger or urine production

- Presence of glucose in urine

Question 9

Causes of type 1 diabetes

Answer 9

-The pancreas fail to secrete enough insulin

Question 10

Effects of type 1 diabetes

Answer 10

• Premature aging
• Cataract formation
• Heart diseases

Question 11

Auxin

Answer 11

A plant hormone that stimulates growth in shoots, but inhibits growth in roots

Question 12

Negative geotropism of plants

Answer 12

1. In the shoots, auxin accumulates on the lower side
2. lower side of the shoot grows faster than the upper side
3. The shoot bends upwards, against gravity

Question 13

Positive phototropism of shoots

Answer 13

1. Auxin accumulates on the shaded side of the shoots
2. The shaded side grows more than the bright side
3. The shoot grows and bends towards the light

Question 14

Positive geotropism in roots

Answer 14

1. In roots, auxin accumulate on the lower side
2. The growth of root is inhibited on the lower side
3. The upper side of the root grows faster than the other side
4. The roots bend downwards into the soil