monthly poster

Friday, 18 October 2013

BIOLOGY 2013 FORECAST SERIES 8 - Homeostasis (O2 & CO2)

Like the role of effectors in responding towards hellish hot & chilling cold stimuli before, now we shall go for the role of effectors in regulating the body in the high altitude & during heavy exercise. 

They have different stimuli, as shown below:

Hence, the questions are these:

Q1: Discuss the role of effectors in regulating the body's amount of O2 in high altitude
Q2: Discuss the role of effectors in regulating the body's amount of CO2 during heavy exercise

Surprisingly, both have the same effectors, which are the INTERCOSTAL MUSCLE and the DIAPHRAGM. (ID)

My freakin' passport ID... damn i was a freakin Taliban...

We learnt before they have different stimuli. But they have the same response. Here is the correct answer scheme:


1. Medulla oblongata (centre of regulation) sends impulses to both intercostal muscle & diaphragm (ID). (2marks)

2. As a result, both increase contraction rate which leads to higher breathing rate. (2marks)

3. Hence, more O2 is inhaled (in high altitude)/ more CO2 is exhaled (during heavy exercise). (1mark).

4. As a result, this would lead to normal level of O2/CO2 in the body. (1mark)



READ CAREFULLY THE QUESTION. If the question asking only about effectors, then only do away with effectors and their response. Do not include receptors as you would spend more time on unnecessary answers. Only include receptors IF THE QUESTIONS ASK YOU SO.

Congratz! You have mastered the spotted Q for this year exam. Now get busy with the other subjects.



  1. ckgu...benarkan saya gunakan nota-nota ckgu smoga ilmu yg manfaat diberkati allah...terima kasih

  2. cikgu heery you are a very good teacher!!!!!!!!!!!!!!!