Lung volume

Lung volumes and lung capacities refer to the volume of air associated with different phases of the respiratory cycle. Lung volumes are directly measured. Lung capacities are inferred from lung volumes.
The average total lung capacity of an adult human male is about 6 litres of air, but only a small amount of this capacity is used during normal breathing.
The breathing mechanism is called respiration. Tidal breathing is normal, resting breathing; the tidal volume is the volume of air that is inhaled or exhaled in a single such breath. It's 0.5 litres

	Average lung volumes in healthy adults
Volume	Men (Value-litres)	Women(Value-litres)
Inspiratory reserve volume	3.3	1.9
Tidal volume	0.5	0.5
Expiratory reserve volume	1.0	0.7
Residual volume	1.2	1.1

Lung capacities in healthy adults

Volume	Men	Women	Derivation /td>
Vital capacity	4.8	3.1	IRV+TV+ERV
Inspiratory capacity	3.8	2.4	IRV+TV
Functional residual capacity	2.2	1.8	ERV+RV
Total lung capacity	6.0	4.2	IRV+TV+ERV+RV

An average human breathes some 12-20 times per minute.
Several factors affect lung volumes; some can be controlled and some cannot. Lung volumes can be measured using the following terms:

Larger volumes	Smaller volumes
taller people	shorter people
non-smokers	smokers
people who live at higher altitudes	people who live at lower altitudes

A person who is born and lives at sea level will develop a slightly smaller lung capacity than a person who spends their life at a high altitude. This is because the partial pressure of oxygen is lower at higher altitude which, as a result means that oxygen less readily diffuses into the bloodstream. In response to higher altitude, the body's diffusing capacity increases in order to process more air.
When someone living at or near sea level travels to locations at high altitudes (eg. the Andes, Tibet, the Himalayas, etc.) that person can develop a condition called altitude sickness because their lungs remove adequate amounts of carbon dioxide but they do not take in enough oxygen. (In normal individuals, carbon dioxide is the primary determinant of respiratory drive.)

Respiratory system vocabulary

alveoli:Little "sacs" at the end of the bronchioles where most of the gas exchange occurs.
asthma:A chronic illness in which the bronchioles are inflamed and become narrow.
bronchitis:An inflammation of the bronchi.
diaphragm:A sheet of muscle that extends across the bottom of the rib cage. When the diaphragm contracts the chest volume gets larger and the lungs take in air; when the diaphragm relaxes, the chest volume gets smaller and air is pushed out of the lungs.
emphysema: A chronic lung disease caused by loss of elasticity of the lung tissue.
epiglottis:A flap of connective tissue that closes over the trachea when food is swallowed to prevent choking or inhaling food.
exhalation:Pushing air out of the body through the nose or mouth.
external respiration:The movement of oxygen into the body and carbon dioxide out of the body.
inhalation:Taking air into the body through the nose and mouth.
internal respiration:The exchange of gases between the blood and the cells of the body.
larynx:Found just below the point at which the pharynx splits into the trachea and the esophagus. Your voice comes from your larynx; air from the lungs passes across thin membranes in the larynx and produces sound; also called the voicebox.
lung cancer:A disease where the cells that line the lungs grow out of control; the growing mass of cells pushes into nearby tissues and can affect how these tissues work.
pathogen: An organism that causes disease in another organism; certain bacteria, viruses, and fungi are pathogens of the respiratory system.
pharynx:A long tube that is shared with the digestive system; both food and air pass through the pharynx.
pneumonia:An illness in which the alveoli become inflamed and flooded with fluid.
respiratory disease
trachea:A long tube that leads down to the chest where it divides into the right and left bronchi in the lungs; also called the windpipe.
tuberculosis (TB): A common and often deadly infectious disease caused by a type of bacterium called mycobacterium.

The Journey of a Breath of Air

When you breath in, oxygen is drawn in through the nose or mouth and down into the lungs. The oxygen then passes across the thin lining of the capillaries and into the blood. The oxygen molecules are carried to the body cells by the blood. Carbon dioxide from the body cells is carried by the blood to the lungs where it is released into the air.
Breathing is only part of the process of delivering oxygen to where it is needed in the body. Gas exchange occurs in the alveoli by passive diffusion of gases between the alveoli and the blood in the capillaries of the lungs.

Diffusion is the movement of substances from an area of higher concentration to an area of lower concentration. The concentration of O2 in the alveoli is at a higher level than in the blood and the concentration of CO2 in the alveoli is at a lower lever than in the blood. O2 molecules diffuse across the thin walls of the alveoli and capillaries and into the blood. Carbon dioxide (CO2) moves out of the blood and into the alveoli in a similar way
The pulmonary artery carries the blood traveling to the lungs and alveoli. Upon reaching the alveoli the blood picks up the inhaled oxygen and at the same time releases the carbon dioxide that needs to be expelled. The pulmonary veins then carry the oxygenated blood to the heart to be pumped through the aorta and around the body. The oxygenated blood travels to the smaller arteries and finally to the capillaries where gas exchange occurs.
The oxygen molecules move out of the capillaries and into the body cells. It is used by the cells to Cellular respiration, the process of breaking down glucose to release energy .
C6H12O6 + 6O2 → 6H2O + 6 CO2 + ENERGY
The waste products of cellular respiration include carbon dioxide and water. The carbon dioxide molecules move out of the cells and into the capillaries that surround the cells. The carbon dioxide is removed from the body by the lungs.

Can you believe it?

Three post on the respiratory system and no video yet, can you believe it?. In this post just in case you are missing the videos, here you have some of them.

The first one is for kids but very clear and easy to understand.


The second one is a reviw of all the parts and organs of the respiratory system.

In the last one of this post you can understand the breathing movement.

Good work and until the next post.

How we breathe

Most of the time, you breathe without thinking of it. Breathing is mostly an involuntary action that is controlled by a part of your brain that also controls your heart beat. If you swim or sing, by instance, you know you can also control your breathing.
The taking in and expelling out of air is done by two movements:Inspiration and expiration. Inspiration: breathing in (a.k.a., inhalation)
Taking air into the body through the nose and mouth. It’s always an active process
caused by muscular contraction, mainly of the diaphragm with the help of intercostal muscles. During inhalation, the diaphragm contracts and moves downward. The rib muscles contract and cause the ribs to move outward. This causes the chest volume to increase. Because the chest volume is larger, the air pressure inside the lungs is less than the air pressure outside. This difference in air pressures causes air to be sucked into the lungs.
Expiration: breathing out (a.k.a., exhalation)
Pushing air out of the body through the nose or mouth It’s typically a passive process caused by elastic recoil of the lungs and relaxation of diaphragm and intercostal muscles. When the diaphragm and rib muscles relax, the chest volume is smaller, the air pressure inside the lungs is bigger than the air pressure outside. This difference in air pressures causes air to be pushed out of the lungs. Exhalation is similar to letting the air out of a balloon.
The lungs cannot move by themselves. As mentioned above, air moves into and out of the lungs by the movement of muscles. The diaphragm and rib muscles contract and relax to move air in to and out of the lungs.
After ventilation, the second stage of breathing is the gas exchange. It takes place in the alveoli. The walls of the alveoli are very thin and are permeable to gases. The alveoli are lined with capillaries, the walls of which are also thin enough to allow gas exchange.
Oxygen diffuses from the alveoli to the blood in the capillaries that surround the alveoli. At the same time, carbon dioxide diffuses in the opposite direction, from capillary blood to the alveoli. At this point, the pulmonary blood is oxygen-rich, and the lungs are holding carbon dioxide. Exhalation follows, thereby ridding the body of the carbon dioxide and completing the cycle of respiration.

A really good finding

I am very happy about this finding. It is a page with a lot of information about different subjects. The good thing is that this page have drawing, text and the sound. You can hear the text at the same time you read it. I think is perfect to learn anything and in English.
So I must recomend this web page schoool.co.uk . In this page site you can find a good explanation of the respiratory system. You only have to click in Lesson - Breathing and Respiration and you will get several page about respiration. I suggest from page 1 to 15 to study the respiratory system and also the page 28 and 29 about smoking.

I think is also a good idea to click in Lesson - digestion to go to the digestive system pages and take a look from the page 8 to the 19. After this you will understand very much better the digestive process.

I encourage you all to use this resource. Perhaps you don't understand one word or more but as you can read the words you will be able to look up in the dictionary . I think that most of the times you will be able to guess the meaning according to the context.

Respiratory system.

Hello everybody, here we are in a new year. I hope you rested in Christmas holidays after all the work of the first quarter. I also assume that you had a good time with your family and friends. But we are in a new year and we must return to work. We have to keep improving our knowing about the human body. In the first quarter we finished with the digestive system. we studied its anatomy and fisiology. Now we continue with the nutrition function and we will study:
The respiratory system:
The main function of the respiratory system is to bring oxygen into the body and releases carbon dioxide into the atmosphere. The respiratory system is made up of the organs that take part in this process. These structures include your nose, mouth, larynx, pharynx, lungs, and diaphragm. These structures are shown in Figure


The nose and nasal cavity filters, warms, and moistens the inhaled air. The nose hairs and mucus produced by the cells that line the nose catch airborne particles and prevent them from reaching the lungs.
Behind the nasal cavity, air next passes through the pharynx, a tube that is shared with the digestive system. Both food and air pass through the pharynx. A flap of connective tissue called the epiglottis closes over the trachea when food is swallowed to prevent choking or inhaling food.
The larynx is found just below the point at which the pharynx splits into the trachea and the esophagus. Your voice comes from your larynx. Air from the lungs passes across thin membranes (vocal cords) in the larynx and produces sound.
The trachea, or wind pipe, is a long tube that leads down to the chest where it divides into the right and left bronchi in the lungs. The bronchi branch out into smaller bronchioles in each lung.
The bronchioles lead to the alveoli.
Alveoli are the little sacs at the end of the bronchioles. They look like little bunches of grapes at the end of the bronchioles, as shown in Figure. Gas exchange occurs in the alveoli, oxygen move across a membrane and into the blood and carbon dioxide move out of the blood. The alveoli are the tiny grape-like structures in the lungs and the sites of gas exchange.
The diaphragm is a sheet of muscle that extends across the bottom of the rib cage. It performs an important function in respiration. When the diaphragm contracts the chest volume gets larger and the lungs take in air. When the diaphragm relaxes, the chest volume gets smaller and air is pushed out of the lungs.