We need energy to fuel all the activities in our bodies, such as contracting muscles and maintaining a resting potential in our neurons, and we have to work to obtain the energy we use.
Green plants take their energy directly from sunlight and convert it into carbohydrates sugars. We cannot do that, but we can use the energy stored in carbohydrates to fuel all other reactions in our bodies. To do this, we need to combine sugar with oxygen. We therefore need to accumulate both sugar and oxygen, which requires us to work.
As a matter of fact, we spend much of our energy obtaining the sugar and oxygen we need to produce energy. We source carbohydrates from green plants or animals that have eaten green plants, and we source oxygen from the air. Green plants release oxygen as a waste product of photosynthesis; we use that oxygen to fuel our metabolic reactions, releasing carbon dioxide as a waste product. Plants use our waste product as the carbon source for carbohydrates. To obtain energy we must release the energy contained in the chemical bonds of molecules such as sugars.
The foods we eat such as carbohydrates and proteins are digested in our gastrointestinal tract into molecules such as sugars and amino acids that are small enough to pass into the blood. The blood transports the sugars to the cells, where the mitochondria break up their chemical bonds to release the energy they contain. Cells need oxygen to be able to carry out that process. As every cell in our body needs energy, every one of them needs oxygen. The energy released is stored in a chemical compound called adenosine triphosphate ATP , which contains three phosphate groups.
When we need energy to carry out an activity, ATP is broken down into adenosine diphosphate ADP , containing only two phosphate groups. Breaking the chemical bond between the third phosphate group and ATP releases a high amount of energy. Our lungs supply oxygen from the outside air to the cells via the blood and cardiovascular system to enable us to obtain energy. As we breathe in, oxygen enters the lungs and diffuses into the blood. It is taken to the heart and pumped into the cells.
At the same time, the carbon dioxide waste from the breakdown of sugars in the cells of the body diffuses into the blood and then diffuses from the blood into the lungs and is expelled as we breathe out. One gas oxygen is exchanged for another carbon dioxide. This exchange of gases takes places both in the lungs external respiration and in the cells internal respiration.
Fig 1 summarises gas exchange in humans. Our respiratory system comprises a conduction zone and a respiratory zone. The conduction zone brings air from the external environment to the lungs via a series of tubes through which the air travels. These are the:. The nasal cavity has a large number of tiny capillaries that bring warm blood to the cold nose. The warmth from the blood diffuses into the cold air entering the nose and warms it. The lining of the pharynx and larynx which form the upper respiratory tract and the lining of the trachea lower respiratory tract have small cells with little hairs or cilia.
These hairs trap small airborne particles, such as dust, and prevent them from reaching the lungs. The lining of the nasal cavity, upper respiratory tract and lower respiratory tract contains goblet cells that secrete mucus.
It also traps particles, which the cilia then sweep upwards and away from the lungs so they are swallowed into the stomach for digestion, rather than getting trapped in the lungs. This mechanism of moving trapped particles in this way is known as the mucociliary escalator. The lungs are a little like balloons: they do not inflate by themselves, but only do so if air is blown into them. We can blow into the lungs and inflate them — which is one of the two techniques used for cardiopulmonary resuscitation — but that does not happen in the normal daily life of healthy people.
We have to inhale and exhale air by ourselves. How do we do that? We have two lungs right and left contained in the thoracic cavity chest. Surrounding the lungs are ribs, which not only protect them from damage but also serve as anchors for the intercostal muscles. Beneath the lungs is a very large dome-shaped muscle, the diaphragm. All these muscles are attached to the lungs by the parietal and visceral membranes also called parietal and visceral pleura.
The parietal membrane is attached to the muscles and the visceral membrane is attached to the lungs. The liquid between these two membranes, pleural fluid, sticks them together just as panes of glass become stuck together when wet. As the visceral membrane covers, and is part of, the lungs and is stuck by pleural fluid to the parietal membrane, when the muscles in the thorax move, the lungs move with them. If air gets between the membranes, they become unstuck and, although the muscles can still contract and relax, they are no longer attached to the lung — as a result, the lung collapses.
This abnormal collection of air in the pleural space is called a pneumothorax. If the pleural fluid liquid becomes infected, the person develops pleurisy. When the intercostal muscles contract, they move up and away from the thoracic cavity. When the diaphragm contracts, it moves down towards the abdomen. This movement of the muscles causes the lungs to expand and fill with air, like a bellows inhalation.
Conversely, when the muscles relax, the thoracic cavity gets smaller, the volume of the lungs decreases, and air is expelled exhalation. Glucose is made in the first place in the leaves of plants from solar energy - the process of photosynthesis is the reverse of respiration. Carbon exists in the earth's atmosphere primarily as the gas carbon dioxide.
This makes up 0. Only 21 per cent of what we inhale is oxygen and of this, per cent is exhaled, the body retaining generally enough for its needs. It seems strange - odd, even - that the odd numbers are usually on the left, even on the right.
There's lots to consider. The problem needs to be addressed. You don't have to be a Rhodes scholar to know that even numbers are streets ahead of those rather odd figures, hence the even numbers are situated on the best side of the street.
I have lived in different towns and in different countries and I have lived on the odd side of the street. Therefore my side is odd and the other side is even!
Almost all local councils here follow the European scheme, ie: odd numbers on the left side, as viewed from the datum point at the start of the road, and even numbers on the right. One of the few things they manage without risking the appointment of an administrator. The odd versus even system is found in most English speaking countries, with the odd numbers being assigned to the western or southerly aspects of a street. In Australia, the boundary between councils may instigate a restart in numbering.
In rural areas where properties are sparse, numbers may be related to the distance from a road's origin. For example a roadside box number would be m from the roads start. The numbering starts from the end closest to the marker with the number one on the right, 2 on the left and so on. It's a dexter conspiracy. As in Europe, Australian addresses use odd numbers on the left side from where the street begins and even numbers on the right.
The street usually starts at the closest point to the nearest GPO in a town or city. Napoleon has often been credited with the idea of odd numbers on one side and even on the other. But different councils have different policies.
In Manly, our family home was No 3 on our road; it was on the left. In Elderslie Camden Municipality , we're No 22 on our street and still on the left.
Odd, isn't it? England had an assistance treaty with Poland, and therfore they would have declared war on Russia. We never hear about the fact that England should also have declared the war on Russia in and not just Germany when they both carved up Poland. It may be a more interesting question to ask: If World War I had ever happened, would Adolf Hitler ever have come to power?
Hitler took Germany into World War II on the back of the failure of the Weimar Republic, rampant poverty and the perceived unfairness of the Treaty of Versailles, which had caused outrage among German nationalists. If Adolf had been bumped off in World War I, it's more than likely that some other fanatic would have plunged the country back into war.
The Nazi Party gained power by exploiting rampant nationalism, including anti-semitism and anti-communism, and propaganda. The ruthlessness of the Nazi takeover may have allowed any leader to take them to war, but in the end it was Hitler's charismatic oratory that erased any misgivings the people might have after WWI, urged them on to fight for Lebensraum "room to live" , and carried them into the ultimate conflict. The tension between Japan and the USA would have sparked off a Pacific war and the tension which later produced the Cold War would have come forward to bring on a conflict in Europe.
Eventually yes. Hitler was the catalyst for World War II to happen, but he wasn't the only dictator. However, it is unknown how the process of isolation and preparation and the ex situ perfusion technique may affect VO 2 under these conditions.
For in vivo assessments of lung VO 2 usually an indirect approach is used. Lung oxygen consumption has been estimated from the difference between VO 2 determined by indirect calorimetry and VO 2 determined by the Fick principle.
While the latter is calculated as the product of systemic arteriovenous oxygen content difference and cardiac output and excludes by definition oxygen extraction of the lung, indirect calorimetry measures whole-body oxygen uptake. Because for this calculation different techniques with inherent imprecision are used blood gas analysis, determination of hemoglobin, oxygen saturation, and cardiac output , the determined lung VO 2 has limited utility.
In a recent case report, lung VO 2 was determined by indirect calorimetry in a patient 2 days after double-lung transplantation requiring extracorporeal membrane oxygenation due to acute lung injury. In summary, we determined lung VO 2 during total CPB when lung gas exchange is separated from the systemic circulation. Sign In or Create an Account.
Advanced Search. Sign In. Skip Nav Destination Article Navigation. Close mobile search navigation Article navigation. Volume 86, Issue 3. Previous Article Next Article. Materials and Methods. Article Navigation. Clinical Science March Loer, MD ; Stephan A. Loer, MD. This Site. Google Scholar. Thomas W. Scheeren, MD ; Thomas W. Scheeren, MD. Author and Article Information. Loer, Scheeren Staff Anesthesiologist. Anesthesiology March , Vol. Get Permissions. Table 1. Demographic Data. View large.
View Large. View large Download slide. Table 2. Lung and Whole Body Gas Exchange. Thierny DF: Lung metabolism and biochemistry. Ann Rev Physiol ; Acta Physiol Scand ; The metabolism of lung as determined by study of slices and ground tissue.
J Biol Chem ; J Appl Physiol ; Am J Physiol ; Pflugers Arch ; Light RB: Intrapulmonary oxygen consumption in experimental pneumococcal pneumonia. Fritts HW: Oxygen consumption of tissues in the human lung.
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