Alveoli

tracheal tubes

membranes must be thin for efficient diffusion of gasses.

Lactiferous Duct

The microvilli and villi in the intestine increase the absorbent surface where nutrients are transported into the blood. The alveoli in the lungs and gill lamellae bring oxygen in the air and water to the bloodstream,

Crackles: Fine crackling or bubbling sounds, commonly heard during inspiration when there is fluid in the alveoli; also called rales.

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Alveoli are expanded chambers of epithelial tissue which form the gas exchange surfaces of the lungs. Multiple alveoli share a common duct forming alveoli sacs.

The minute structures that end in the alveoli of the lungs are called bronchioles. These small airways branch from the larger bronchi and lead directly to the alveolar sacs, where gas exchange occurs. Alveoli are tiny air sacs that facilitate the exchange of oxygen and carbon dioxide between the air and blood.

Oxygen is, of course, a gas our bodies are dependent on and need for us function properly. However, our body doesn't produce oxygen yet it is present in our external environment (in the air). So our body has specific structures and systems in place to function to extract this gas from the environment so we can use it. We breath in oxygen and it enters the alveoli in our lungs which are like tiny air sacs. These sacs are covered by a thin film of moisture and are also in close proximity to a complex network of blood cappilaries. Substances move accross membranes through diffusion which is due to a difference in concentrations of that substance on both sides of the membrane. The movement occurs from places of high concentration to places of lower concentration, down the concentration gradient, thus, it is a passive process. The blood that has pumped around our body has been depleted of oxygen as our body cells have taken it up which leaves the blood that comes to the alveoli deoxygenated and low in concentration of oxygen (however it is is high in concentration of CO2 which is a waste product of cellular respiration). When we breathe in, the air that enters are lung is full of oxygen (infact about 20.95%) thus we can say that there is higher concentration of o2 in the alveoli than there is in the blood. This triggers diffusion to occur from the alveoli to the blood hence we can say that differences in concentration causes it diffuse over. The gas has to pass through that thin film of moisture which is essential as gases can only be exchanged in a dissolved form. hope this helps, email mitchcook@live.com for further explanation

carbon dioxide

Carbon dioxide leaves the blood and goes into the alveoli where it can then be breathed out of the body. It is also at this point that oxygen passes into the blood to be carried to where it is required for respiration - carbon dioxide being a by-product of respiration.

surfactant

Ventilation

There is no specific term that describes a burst alveolar sac. There is a term for the collapse of an alveolar sac (usually due to insufficient presence of surfactant), and that term is ATALECTASIS.

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The surfactant doesn't allow the sides of the alveoli form sticking together. Infants that are born very early don't make surfactant and so have many problems.

Alveoli are little air sacs found in bunches (like grapes) at the end of terminal bronchioles. Alveoli are where gas exchange (oxygen goes into blood and carbon dioxide out of blood) happens as they have sufficiently thin walls and suitably large total surface areas for gas exchange to occur.

alveoli are arranged in grape like groups to increase surface area in which gas exchange takes place, the walls are very thin just big enough for on cell to pass so that there is an increase in rate of diffusion, walls of alveoli are moist so it also increases the rate of diffusion and the alveoli can stretch so that it prevents the alveoli form over filling with air and damaging the thin walls

its smaller

They Have A large surface area and they are full of red blood cells

nothing

because it keeps all the nitro oxide in.

lower exchange rate,takes longer for gases to diffuse

Pneumonia leading to consolidation and collapse.