URGENT HELP!!! Biology Homework questions that I don't understand!!

Hi, thanks for reading this. We have just done a PAG and I need answers to these extension questions that I have no clue what the answers are of.

1) Using a calibrated eyepiece graticule the mean diameter of an alveolus is measured to be 170 micrometres. Do you think this sounds too small, too large or about right? What is the reasoning behind your answer? (HINT: Before you even make your own measurements, how do you roughly know how large an alvelous must be based on your own knowledge and what you can see in your specimen)

2) Why is it difficult to see blood capillaries?

3) Why are bronchioles so numerous? Why are capillaries so numerous?

4) Why are lung arterioles relatively thin-walled?

5) Explain how the features of lung structure seen on these slides account for efficient gas exchange in the lungs.

We basically saw alveoli in the microscope, that's it. Our teacher didn't really make us do any 'measurements' too for question 1. So I'd be eternally grateful if anyone helps with these questions... Thank you all so so much! :biggrin:

Reply 1

hello654321

number four is probably that the thin walls mean faster diffusion of o2 in and co2 out

Reply 2

AfcFob

1) Reasonable- think about the size of the lungs
2) Capillaries are a very similar diameter to that of an RBC- think about how small that is
3)Never had to answer the bronchioles thing, it sounds like to put O2 into more alveoli (hence greater area for O2 diffusion). Capillaries are the site of O2 diffusion into cells- there's a lot of cells in the body
4) Reducing the diffusion pathway, what would this do to the rate of diffusion and what is the benefit?
5) Can't answer as I have not seen these slides, you have to answer for yourself

Feel free to PM me as you seem to be in AS which I got an A in last year

(edited 7 years ago)

Reply 3

Mimir

Hello Foundation Module Biology - it's been a while. Ok I've got some suggestions.

Original post by akash3141

1) Using a calibrated eyepiece graticule the mean diameter of an alveolus is measured to be 170 micrometres. Do you think this sounds too small, too large or about right? What is the reasoning behind your answer? (HINT: Before you even make your own measurements, how do you roughly know how large an alveolus must be based on your own knowledge and what you can see in your specimen.

You will know what the mean diameter of an erythrocyte is? I think it's 6um [micrometers] off the top of my head but I might be very wrong). Think about the function of the alveolus and the size in relation to that, and the function of the alveoli. There's your answer.

2) Why is it difficult to see blood capillaries?

Think about their composition - why is this important, and where are they most prolific, and what happens there? The question follows on from the previous question. Consider what it is easiest to see (you could identify the muscular layer in an artery no problem, for example, but which layer would you struggle to identify even in an artery? It's the same (sort of)).

3) Why are bronchioles so numerous? Why are capillaries so numerous?

I seem to have preempted this. Think about diffusion and osmosis, that sort of thing. What makes it happen faster/slower. Will more erythrocytes help this? Think about what might happen if the RBCs became saturated, and how the body is likely to be avoiding this.

4) Why are lung arterioles relatively thin-walled?

See previous. Consider your diffusion, osmosis etc.

5) Explain how the features of lung structure seen on these slides account for efficient gas exchange in the lungs.

Read the chapter in your textbook, it will give you the answers to this. I don't know the depth of knowledge required for this, suffice to say you need to consider the distance gases need to travel, the amount that needs to be exchanged, the importance of this on the body, the importance of this in the CV system, and several other things.

That should give you a decent start/check to the answers you already have. I daren't give in depth or comprehensive answers because I don't know the marking criteria and I'd likely confuse you.