Why Total Surface Area/ Volume Matters?

What is actually the Total Surface Area over Volume (TSA/V) thing that we learnt in the first thing in Chapter 1 (Transport) in Form 5? Here, we shall discover more about the confusing concept:

First, see the diagram of cells below:

As you can see, the large animals have LESS CELLS EXPOSED FOR DIFFUSION of substances compared to its volume or size.

Diagram: 14 cells exposed compared to overall 27 cells --> 14/27 = 0.52

The small animal, it has MORE CELLS EXPOSED FOR DIFFUSION of substances compared to its volume or size.

Diagram: 5 cells exposed compared to overall 6 cells --> 5/6 = 0.83 (HIGHER TSA/V)

That explains why large animals such as whales have a VERY LOW HEARTBEAT RATE. This is because the heart doesn't need to pump much because the large size can retain more heat & substances in the body (heat is difficult to diffuse out because of less cells for diffusion).

My heart beats 6 times per minute...

Compared to small animals such as mouse. it has a VERY HIGH HEARTBEAT RATE. This is because the body cells constantly need to replace lost heat/substances thanks to the high diffusion rate.

My heart beats more than 600 times per minute!!!

Now you know :-) See you in the next post!

One more thing, I want you to ponder this...

Q: Why big/obese individuals have HIGHER HEARTBEAT RATE than normal ones?????

Is it violating the TSA/V rule? Google now & let me know.