Gas Exchange: The Structure of the Lungs | A-level Biology | OCR, AQA, Edexcel

Gas Exchange: The Structure of the Lungs in a Snap! Unlock the full A-level Biology course at bit.ly/2ZagyJm created by Adam Tildesley, Biology expert at SnapRevise and graduate of Cambridge University.
The key points covered of this video include:
1. Introduction to the Lungs
2. Trachea and Bronchi
3. Bronchioles
4. Alveoli
Introduction to the Lungs
Mammals require a large amount of oxygen and produce a large amount of carbon dioxide. They are large organisms, they have a high metabolic rate and level of activity. To deal with these constraints mammals evolved lungs.
The Trachea and Bronchi
The trachea and bronchi connect the lungs to the mouth. They contain many C-shaped rings of cartilage to provide support and flexibility. This diagram shows a cross-section of a bronchus as would be seen under a microscope. Smooth muscle allows them to constrict to reduce air flow. The walls are line with ciliated epithelial tissue containing goblet cells. Goblet cells secrete mucus that traps dirt and pathogens. Ciliated epithelium wafts mucus up out of the airways.
Bronchioles
The bronchioles lead from the two bronchi to the alveoli. The bronchi consist mainly of smooth muscle and epithelial cells. Larger ones may have cartilage but most do not.
The Alveoli
The lungs consist mostly of millions of alveoli. Alveoli consist of squamous epithelial tissue and elastic fibres. This is a micrograph of a section of lung tissue showing alveoli. The alveoli show a variety of adaptations that suit them to gas exchange: Large surface area and good blood supply, short diffusion distance for gasses to travel.
Summary
Lungs are highly complex gas exchange organs
The alveoli are gas-filled sacs specialised for gas exchange
The trachea, bronchi and bronchioles deliver gasses to and from the alveoli
The functions on different parts of the lungs are represented in their structures that show their specific adaptations towards carrying out their roles

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No cap

[@Miquelalalaa]

Do you know what the first video for topic 3 is?

[@snaprevise]

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I have like 4 lessons of bio to catch up on. this quarantine will be sooooo fun

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yp still

[@zaynabmalik806]

Very helpful especially as im taking biology for a levels next year!

[@snaprevise]

Glad it was helpful! Good luck!!

[@lungilemanungo3586]

have an exam this morning and hes helped me understand

[@infinityClouds]

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[@madzlogtv1484]

Please make a Playlist for EDUQAS WJEC because alot of people do this examboard. It will help me out alot because this examboard is very specific so i need to learn alot

[@rimshaasif689]

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[@snaprevise]

You're so welcome! Glad it was helpful!

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Could you do a video covering smoke cigarrettte and emphysema and COPD

[@sambhavadhikari461]

You just saved me from failing my bio assessment

[@snaprevise]

Glad it helped! 🐱‍🏍

[@dilukshfernando3936]

Start at 1:45 (Don't mind me just keep a time stamp for personal use)

[@the_self-standing]

When you're sick and you got mucus build up how come when mucus enters your mouth and when you swallow it down you feel like it's still clogging your throat giving you a cough?... doesn't that mean mucus doesn't go to the stomach? How does the epiglottis know its meant to go to the stomach?... since its not food. Edit: Does the epiglottis close off the windpipe when you cough? Allowing mucus to go down the stomach pathway?

[@teecee6655]

Thank you♥️

[@maiz3558]

have u done the whole ocr spec?

[@BFR-jc5np]

do you not need to know about the nasal cavity

[@Aya-jk3xx]

Thank you

[@Hamza-kg4ko]

in the edexcel mark scheme, it says that the alveoli are just one cell thick instead of two?

[@ardowsuiyesi7932]

The alveoli are one cell thick. The diffusion distance from the alveoli to blood vessel is two cell thick because it includes the blood vessel wall as well which is one cell thick too.

[@winniethepooh8766]

you got the alveolar epithelium and epithelium of capillary

[@salmamamdouh4678]

so when they ask about the adaptations of alveoli, do we say it's one cell thick or 2 cells thick?

[@Wasteman365]

The WALL is one cell thick

[@riverelliot6337]

The wall is one cell thick and then the wall of the capillary is one cell thick. But you could say that it’s adapted for gas exchange because it only has to travel through two cells

[@Wasteman365]

2:35 lmao imagine the rest of the head there

[@kimberlygillian9230]

thank you so much, this was really helpful

[@momangal1543]

So these C shaped cartilage act in a similar way to the chitin surrounding the trachea of insects?

[@aniqahbuckingham7947]

Yep😉

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Nice video, keep it up man :)))))))

[@snaprevise]

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Nice

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Nice video

[@snaprevise]

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[@snaprevise]

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nice

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Thank you! We're glad that you like it! 👍

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