Always a part of you

Most living things are made up of one or more cells. These are more cells from our bodies and from plants.


This is a high magnification SEM of a tiny portion of a rabbit lung. Mammals, birds and reptiles have lungs, as do most amphibians and a few kinds of fish. In humans air travels to the lungs through the nose or mouth, down the throat and trachea (windpipe). In the chest the trachea divides into two branches, the bronchial tubes, that go to the lungs.

The bronchial tubes eventually narrow down to bronchioles, about 1 mm or less in diameter. These then divide into even narrower tubes called alveolar ducts (orange). Each alveolar duct ends in a cluster of thin-walled sacs only one cell thick, the alveoli (yellow). This is where the gas exchange takes place.

Each alveolus is surrounded by a network of tiny blood capillaries (red). Blood comes in via arteries, and empties into veins which take it back to the heart. Oxygen from the alveoli diffuses across the alveoli cells into the blood, where it is taken to the heart. At the same time, poisonous carbon dioxide which is a byproduct of animal metabolism, moves out of the blood and into the lungs, where it can be exhaled.

There are a lot of diseases of the lung, the worst of which are caused by smoking tobacco. If you saw a picture of a healthy lung, and then the lung of a smoker, you would surely never smoke! This rabbit's lung was very healthy and pink.

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Lung    Skin 1    Skin 2    Skin 3    Cell Surface   
Red Blood Cells    Red Blood    Red Blood Cell    Macrophage    Sperm   
Muscle TEM    Golgi    Mitochondria    Synapse   
Cell - TEM    Cell - TEM    Stomata    Stomata 2   


Copyright © 1996-2000 Tina (Weatherby) Carvalho...MicroAngela
This material may not be reproduced in any form without express written permission.