how does carbon dioxide diffuse from the blood into the alveoli?
103922
Oxygen breathed into the lungs diffuses into the alveoli, and then passes through into the  capillary walls. Here it turns into oxyhaemoglobin. Carbon dioxide is carried by blood into the alveoli and is breathed out of the lungs.\n\nGases diffuse along pressure gradients. In other words, gases spread from high concentration areas to low-concentration areas.\n\nThe blood in the capillaries arriving at the alveoli is low in oxygen and high in carbon dioxide. Air in the alveoli is high in oxygen and low in carbon dioxide. \n\nTherefore oxygen diffuses into the blood (attaching itself to the haemoglobin), and carbon dioxide diffuses into the alveoli, where it is breathed out.\n\nThe reverse process occurs at the capillaries that surround the muscle fibres
304400
The chemical reaction by which oxygen + hemoglobin -> oxyhemoglobin occurs has a chemical equalibrium, and this is exploited in the lungs (where the forward reaction occurs due to the higher atmospheric concentration of oxygen causes oxygen + hemoglobin to bind), in tissues (where the reverse reaction occurs due to lower concentrations of oxygen in the working tissues than in the blood, and the reaction proceeds backwards more due to the presence of carbonic acid).\n\nA similar situation happens with CO2, to remove it from the cells. Now, incidentally, in the blood, much of the CO2 takes the form of carbonic acid. Lowering the pH of the blood decreases the binding affinity of oxygen and hemoglobin, releasing oxygen to the working tissues (those which have a high rate of metabolism, and are, therefore, releasing lots of CO2).
16906
First you must know the following equation, which explains how the body \nbuffers the blood and removes carbon dioxide from tissues:\n\nHCO3- + H <-> H2CO3 <-> CO2 + H2O\n\nTheroretically, they are all in equilibrium. When you are hyperventilating, you are releasing an EXCESS of CO2. That means that in order to maintain equilibrium, you must make more CO2 (since you are getting rid of so much at one time). Therefore, you are using up hydrogen ions and producing CO2; this makes your blood alkaline (higher pH) because there are less protons (hydrogen ions). \n\nThis condition is known as respiratory alkalosis, because you are literally causing your blood to become alkaline from hyperventilating.
634757
Oxygen Transport\nIn the lungs, oxygen diffuses from alveolar air into the blood because the venous blood has a lower partial pressure. The oxygen dissolves in the blood. Only a small amount is carried as a physical solution (0.31 ml per 100 ml). The remainder of the oxygen is carried in chemical combination with the hemoglobin in red blood cells (erthrocytes).\n\nfrom http://www.elmhurst.edu/~chm/vchembook/260acidbasebal.html\n\n\nNormal analysis results\nNormal blood gas values are as follows:\n partial pressure of oxygen (PaO2): 75-100 mm Hg \n\n\nfrom http://www.healthatoz.com/healthatoz/Atoz/ency/blood_gas_analysis.jsp
472939
Air travels to the lungs through a series of air tubes and passages. It enters the body through the nostrils or the mouth, passing down the throat to the larynx, or voice box, and then to the trachea, or windpipe. In the chest cavity the trachea divides into two branches, called the right and left bronchi or bronchial tubes, that enter the lungs.\n\nIn the adult human, each lung is 25 to 30 cm (10 to 12 in) long and roughly conical. The left lung is divided into two sections, or lobes: the superior and the inferior. The right lung is somewhat larger than the left lung and is divided into three lobes: the superior, middle, and inferior. The two lungs are separated by a structure called the mediastinum, which contains the heart, trachea, esophagus, and blood vessels. Both right and left lungs are covered by an external membrane called the pleura. The outer layer of the pleura forms the lining of the chest cavity.\n\nThe branches of the bronchi eventually narrow down to tubes of less than 1.02 mm (less than 0.04 in) in diameter. These tubes, called bronchioles, divide into even narrower tubes, called alveolar ducts. Each alveolar duct ends in a grapelike cluster of thin-walled sacs, called alveoli (a single sac is called an alveolus). From 300 million to 400 million alveoli are contained in each lung. The air sacs of both lungs have a total surface area of about 93 sq m (about 1000 sq ft), nearly 50 times the total surface area of the skin.\n\nIn addition to the network of air tubes, the lungs also contain a vast network of blood vessels. Each alveolus is surrounded by many tiny capillaries, which receive blood from arteries and empty into veins. The arteries join to form the pulmonary arteries, and the veins join to form the pulmonary veins. These large blood vessels connect the lungs with the heart.\n\n© 1993-2003 Microsoft Corporation. All rights reserved.
1159586
People tend to hyperventilate (breathe fast, without giving the body time to process the air exchange) when stressed.  This causes low levels of carbon dioxide in your blood.  In the past, the remedy was to breathe into a paper bag, thus reducing the amount of oxygen you were taking in and increasing the CO2.  Breathing through a paper bag is NO LONGER RECOMMENDED because this can quickly lead to too much carbon dioxide in your blood stream. \n\nNowadays, to increase your carbon dioxide, you need to take in less oxygen. To accomplish this, you can breath through pursed lips (as if you are blowing out a candle) or you can cover your mouth and one nostril, breathing through the other nostril.
572824
respiration..\n\nco2 is given off, it goes through our blood stream, reabsorbed by the alveoli, switched out with o2 by respiration
1095196
Deoxygenated blood enters the right atrium of your heart which delivers the blood to you right ventricle.  The right ventricle pumps blood to your lungs where the carbon dioxide is dumped for exhalation and the oxygen is loaded onto the hemoglobin molecules in the blood.  Then the oxygenated blood is delivered to your left atrium which then fills your left ventricle.  The muscles in the walls of your left ventricle are thick because they pump blood out of your heart, through your aorta and to the rest of your body - a very big job!
866727
Atmospheric carbon dioxide.
227115
air is moved into the lungs
549228
A rythmic expulsion of carbon dioxide which aids in maintaining the proper pH balance in the bloodstream in order to maintain life.
1109512
The Circulation of Blood\n\nThe human circulatory system is really a two-part system whose purpose is to bring oxygen-bearing blood to all the tissues of the body. When the heart contracts it pushes the blood out into two major loops or cycles. In the systemic loop, the blood circulates into the body’s systems, bringing oxygen to all its organs, structures and tissues and collecting carbon dioxide waste. In the pulmonary loop, the blood circulates to and from the lungs, to release the carbon dioxide and pick up new oxygen. The systemic cycle is controlled by the left side of the heart, the pulmonary cycle by the right side of the heart. Let’s look at what happens during each cycle:\n\nThe systemic loop begins when the oxygen-rich blood coming from the lungs enters the upper left chamber of the heart, the left atrium. As the chamber fills, it presses open the mitral valve and the blood flows down into the left ventricle. When the ventricles contract during a heartbeat, the blood on the left side is forced into the aorta. This largest artery of the body is an inch wide. The blood leaving the aorta brings oxygen to all the body’s cells through the network of ever smaller arteries and capillaries. The used blood from the body returns to the heart through the network of veins. All of the blood from the body is eventually collected into the two largest veins: the superior vena cava, which receives blood from the upper body, and the inferior vena cava, which receives blood from the lower body region. Both venae cavae empty the blood into the right atrium of the heart.\n\nFrom here the blood begins its journey through the pulmonary cycle. From the right atrium the blood descends into the right ventricle through the tricuspid valve. When the ventricle contracts, the blood is pushed into the pulmonary artery that branches into two main parts: one going to the left lung, one to the right lung. The fresh, oxygen-rich blood returns to the left atrium of the heart through the pulmonary veins.\n\nAlthough the circulatory system is made up of two cycles, both happen at the same time. The contraction of the heart muscle starts in the two atria, which push the blood into the ventricles. Then the walls of the ventricles squeeze together and force the blood out into the arteries: the aorta to the body and the pulmonary artery to the lungs. Afterwards, the heart muscle relaxes, allowing blood to flow in from the veins and fill the atria again. In healthy people the normal (resting) heart rate is about 72 beats per minute, but it can go much higher during strenuous exercise. Scientists have estimated that it takes about 30 seconds for a given portion of the blood to complete the entire cycle: from lungs to heart to body, back to the heart and out to the lungs.\n\n^_^
501986
The oxygen is collected by the red cells in the alveolis (in the lungs), they travel all the way trough your body providing oxigenation to all the extremities. When the blood contains oxygen its colour turns pure red but when it caries Carbon Dioxide it turns darker.
225986
I'm going with B on this one.  The pulmonay arteries are taking deoxygenated blood away from the heart to the lungs to pick up O2 and drop off CO2.  This would mean that this blood is as full of CO2 as it can be in the body - at least in healthy people.\n\nC, the pulmonary arteries have just dropped off their CO2, so they don't have much. Not it.\n\nD, I think if the PCO2 were higher here than in the blood, then CO2 would diffuse out of the lungs and into the blood. Not it.\n\nE, The CO2 from the interstitial fluid is always diffusing into the veinous blood.  It's kept at a fairly constant rate, so that's probably not it.\n\nA, this could be the answer.  Honestly I don't know the PCO2 of the atmospheric air, but it would make sense to me that it's lower than what's in the pulmonary arteries because, again, CO2 that you breathed in would diffuse INTO the blood instead of out of it.
608209
Respiration removes carbon dioxide which, when in the body, forms carbonic acid in the blood. Too much carbonic acid and you will suffer from acidosis. In addition to keeping the blood at the correct pH, respiration supplies oxygen to the blood and tissues, such as muscle so that they too, can function correctly.\nSo, homeostasis is when all systems and fluids and tissues are "balanced", or in their correct working state. By removing carbon dioxide, respiration helps to keep the blood (and the body) in homeostasis.
1049982
The lungs are a rich lattice of alveoli, which provide an enormous surface area for gas exchange. A network of fine capillaries allows transport of blood over the surface of alveoli. Oxygen from the air inside the alveoli diffuses into the bloodstream, and carbon dioxide diffuses from the blood to the alveoli, both across the exceptionally thin alveolar membranes. The drawing and expulsion of air is driven by muscular action.
849586
CO2 From the Air, Through the Stoma, H2O from the Xylem.