The Magnificent Respiration System

By;Tyquasia Pittman ,Ahleya Best,Takerra Carney

Respiration concept

RESPIRATION CONCEPT Respiration is much more than just breathing; in fact, the

term refers to two separate processes, only one of which is the intake and outflow of breath. At least cellular respiration, the process by which organisms convert food into chemical energy, requires oxygen; on the other hand, some forms of respiration are anaerobic, meaning that they require no oxygen. Such is the case, for instance, with some bacteria, such as those that convert ethyl alcohol to vinegar. Likewise, an anaerobic process can take place in human muscle tissue, producing lactic acid—something so painful that it feels as though vinegar itself were being poured on an open sore.

Cellular Respiration

Cellular Respiration Both forms of respiration involve oxygen, but cellular

respiration also involves a type of nutrient—materials that supply energy, or the materials for forming new tissue. Among the key nutrients are carbohydrates, naturally occurring compounds that consist of carbon, hydrogen, and oxygen. Included in the carbohydrate group are sugars, starches, cellulose, and various other substances.

Glucose is a simple sugar produced in cells by the breakdown of more complex carbohydrates, including starch, cellulose, and such complex sugars as sucrose (cane or beet sugar) and fructose (fruit sugar).

Lungs

lung The respiratory organ of air-breathing vertebrates. A pair of lungs is situated in the thorax, within the ribcage. Each consists essentially of a thin moist membrane that is folded to increase its surface area. Exchange of oxygen and carbon dioxide takes place between blood capillaries on one side of the membrane and air on the other. The lung is supplied with air through a bronchus. In mammals and reptiles the membrane of the lung takes the form of numerous sacs (see alveolus) that are connected to the bronchus via bronchioles(see illustration). The lungs themselves contain no muscular tissue and are ventilated by respiratory movement the mechanisms of which vary with the species.

Forms of respiration

Forms of Respiration Respiration can be defined as the process by which an organism takes in oxygen

and releases carbon dioxide, one in which the circulating medium of the organism (e.g., the blood) comes into contact with air or dissolved gases. Either way, this means more or less the same thing as breathing. In some cases, this meaning of the term is extended to the transfer of oxygen from the lungs to the bloodstream and, eventually, into cells or the release of carbon dioxide from cells into the bloodstream and thence to the lungs, from whence it is expelled to the environment. Sometimes a distinction is made between external respiration, or an exchange of gases with the external environment, and internal respiration, an exchange of gases between the body's cells and the blood, in which the blood itself "bathes" the cells with oxygen and receives carbon dioxide to transfer to the environment.

This is just one meaning—albeit a more familiar one—of the word respiration. Respiration also can mean cellular respiration, a series of chemical reactions within cells whereby food is "burned" in the presence of oxygen and converted into carbon dioxide and water. This type of respiration is the reverse of photosynthesis, the process by which plants convert dioxide and water, with the aid of solar energy, into complex organic compounds known as carbohydrates. (For more about carbohydrates and photosynthesis, see Carbohydrates.)

How gases move through your body

How Gases Move Through the Body Later in this essay, we discuss some of the ways in which various life-forms

breathe, but suffice it to say for the moment—hardly a surprising revelation!—that the human lungs and respiratory system are among the more complex mechanisms for breathing in the animal world. In humans and other animals with relatively complex breathing mechanisms (i.e., lungs or gills), oxygen passes through the breathing apparatus, is absorbed by the bloodstream, and then is converted into an unstable chemical compound (i.e., one that is broken down easily) and carried to cells. When the compound reaches a cell, it is broken down and releases its oxygen, which passes into the cell.

On the "return trip"—that is, the reverse process, which we experience as exhalation—cells release carbon dioxide into the bloodstream, where it is used to form another unstable chemical compound. This compound is carried by the bloodstream back to the gills or lungs, and, at the end of the journey, it breaks down and releases the carbon dioxide to the surrounding environment. Clearly, the one process is a mirror image of the other, with the principal difference being the fact that oxygen is the key chemical component in the intake process, while carbon dioxide plays the same role in the process of outflow.

The mechanics of breathing

The Mechanics of Breathing All animals have some mechanism for removing oxygen from the air and transmitting it into the

bloodstream, and this same mechanism typically is used to expel carbon dioxide from the bloodstream into the surrounding environment. Types of animal respiration, in order of complexity, include direct diffusion, diffusion into blood, tracheal respiration, respiration with gills, and finally, respiration through lungs. Microbes, fungi, and plants all obtain the oxygen they use for cellular respiration directly from the environment, meaning that there are no intermediate organs or bodily chemicals, such as lungs or blood. More complex organisms, such as sponges, jellyfish, and terrestrial (land) flatworms, all of which have blood, also breathe through direct diffusion. The latter term describes an exchange of oxygen and carbon dioxide directly between an organism, or its bloodstream, and the surrounding environment.

More complex is the method of diffusion into blood whereby oxygen passes through a moist layer of cells on the body surface and then through capillary walls (capillaries are small blood vessels that form a network throughout the body) and into the bloodstream. Once oxygen is in the blood, it moves throughout the body to different tissues and cells. Among the organisms that rely on diffusion into blood are annelids, a group that includes earthworms, various marine worms, and leeches.

In tracheal respiration air moves through openings in the body surface called spiracles. It then passes into special breathing tubes called tracheae that extend into the body. The tracheae divide into many small branches that are in contact with muscles and organs. In small insects, air simply moves into the tracheae, while in large insects, body movements assist tracheal air movement. Insects and terrestrial arthropods (land-based organisms with external skeletons) use this method of respiration.

Much more complicated than tracheae, gills are specialized tissues with many infoldings. Each gill is covered by a thin layer of cells and filled with blood capillaries. These capillaries take up oxygen dissolved in water and expel carbon dioxide dissolved in blood. Fish and other aquatic animals use gills, as did the early ancestors of humans and other higher animals. A remnant of this chapter from humans' evolutionary history can be seen in the way that an embryo breathes in its mother's womb, not by drawing in oxygen through its lungs but through gill-like mechanisms that disappear as the embryo develops.

Humans and anaerobic respiration

Even in creatures, such as humans, that depend on aerobic respiration, anaerobic respiration can take place. Most cells are able to switch from aerobic to anaerobic respiration when necessary, but they generally are not able to continue producing energy by this process for very long. For example, a person who exercises vigorously may be burning up glucose faster than oxygen is being pumped to the cells, meaning that cellular respiration cannot take place quickly enough to supply all the energy the body needs In that case, cells switch over to anaerobic respiration, which results in the production of lactic acid, or C3H6O3. One advantage of anaerobic respiration is that it can take place very quickly and in short bursts, as opposed to aerobic respiration, which is designed for slower and steadier use of muscles. The disadvantage is that anaerobic respiration produces lactic acid, which, when it builds up in muscles that are overworked, causes soreness and may even lead to cramps.

Anaerobic respiration

Anaerobic Respiration Activity that involves oxygen is called aerobic; hence the term aerobic

exercise, which refers to running, calisthenics, biking, or any other form of activity that increases the heart rate and breathing. Activity that does not involve oxygen intake is called anaerobic. Weightlifting, for instance, will increase the heart rate and rate of breathing if it is done intensely, but that is not its purpose and it does not depend on the intake and outflow of breath. For that reason, it is called an anaerobic exercise—though, obviously, a person has to keep breathing while doing it.

In fact, a person cannot consciously stop breathing for a prolonged period, and for this reason, people cannot kill themselves simply by holding their breath. A buildup of carbon dioxide and hydrogen ions (electrically charged atoms) in the bloodstream stimulates the breathing centers to become active, no matter what we try to do. On the other hand, if a person were underwater, the lungs would draw in water instead of air, and though water contains air, the drowning person would suffocate

Lactic and the body

LACTIC ACID IN THE BODY. Eventually, the buildup of lactic acid is carried away in the

bloodstream, and the lactic acid is converted to carbon dioxide and water vapor, both of which are exhaled. But if lactic acid levels in the bloodstream rise faster than the body can neutralize them, a state known as lactic acidosis may ensue. Lactic acidosis rarely happens in healthy people and, more often than not, is a result of the body's inability to obtain sufficient oxygen, as occurs in heart attacks or carbon monoxide or cyanide poisoning or in the context of diseases such as diabetes.

The ability of the body to metabolize lactic acid is diminished significantly by alcohol, which impairs the liver's ability to carry out normal metabolic reactions. For this reason, alcoholics often have sore muscles from lactic acid buildup, even though they may not exercise. Lactic acid also can lead to a buildup of uric acid crystals in the joints, in turn causing gout, a very painful disease