the exchange of oxygen
and carbon dioxide
between the atmosphere and the body cells, including inhalation
of oxygen from the pulmonary alveoli to the blood and of carbon dioxide from the blood to the alveoli, followed by the transport of oxygen to and carbon dioxide from the body cells. See also ventilation
(def. 2) and see Plates.
the metabolic processes by which living cells break down carbohydrates, amino acids, and fats to produce energy in the form of adenosine triphosphate
(ATP); called also cell respiration
The Respiratory Sequence
. The sequence of the respiration process begins as air enters the corridors of the nose or mouth, where it is warmed and moistened. The air then passes through the pharynx, larynx, and trachea and into the bronchi.
The bronchi branch in the lungs into smaller and smaller bronchioles, ending in clusters of tiny air sacs called alveoli
; there are 750 million alveoli in the lungs. The blood flows through the lungs in the pulmonary circulation
. Through the thin membrane of the network of capillaries around the alveoli, the air and the blood exchange oxygen and carbon dioxide. The carbon dioxide molecules migrate from the erythrocytes in the capillaries through the porous membrane into the air in the alveoli, while the oxygen molecules cross from the air into the red blood cells.
The erythrocytes proceed through the circulatory system, carrying the oxygen in loose combination with hemoglobin
and giving it up to the body cells that need it. In cellular respiration the blood cells release oxygen and pick up carbon dioxide. The lungs dispose of the carbon dioxide, left there by the red blood cells, in the process of breathing. With each breath, about one-sixth of the air in the lungs is exchanged for new air.
. The lungs inflate and deflate 16 to 20 times per minute in adults, 12 to 20 per minute in teenagers, 20 to 30 per minute in children 2 to 12 years old, and 30 to 50 per minute in newborns. Their elastic tissue allows them to expand and contract like a bellows worked by the diaphragm and the intercostal muscles. The diaphragm contracts, flattening itself downward, and thus enlarges the thoracic cavity. At the same time the ribs are pulled up and outward by the action of the narrow but powerful intercostal muscles that expand and contract the rib cage. As the chest expands, the air flows in. Exhalation occurs when the respiratory muscles relax and the chest returns automatically to its minimum size, expelling the air (see also lung
Automatic Breathing Controls.
The automatic control of breathing stems from poorly defined areas known as the respiratory centers
, located in the medulla oblongata and pons. From there, impulses are sent down the spinal cord to the nerves that control the diaphragm, and to the intercostal muscles. Chemical and reflex signals control these nerve centers. (See hering-breuer reflexes
The chemical controls of breathing are mainly dependent on the level of carbon dioxide
in the blood. The response is so sensitive that if the carbon dioxide level increases two-tenths of 1 per cent, the respiratory rate increases automatically to double the amount of air taken in, until the excess of carbon dioxide is eliminated. It is not lack of oxygen but excess of carbon dioxide that causes this instant and powerful reaction.
The carbon dioxide tension
), of arterial blood normally is 35 to 45 mm Hg. When the Pco2
increases, the respiratory centers
are stimulated and breathing becomes more rapid; conversely, decrease of the Pco2
slows the rate of respiration. The Pco2
acts both directly on the respiratory centers and on the carotid
and aortic bodies
, chemoreceptors that are responsive to changes in blood Pco2
, and pH (see also blood gas analysis
Protective Respiratory Mechanisms
. The lungs are constantly exposed to the surrounding atmosphere. Twenty times a minute, more or less, they take in a gaseous mixture, along with whatever foreign particles happen to be suspended in it and at whatever temperature it may be. To compensate, the lungs have some remarkable protective devices.
On its way through the nasal passage, the cold air from outside is preheated by a large supply of blood, which gives off warmth through the thin mucous membrane that lines the respiratory tract. This same mucous lining is always moist, and dry air picks up moisture as it passes.
Dust, soot, and bacteria are filtered out by a barrier of cilia
, tiny hairlike processes that line the passageways of the respiratory tract. The cilia trap not only foreign particles but also mucus produced by the respiratory passages themselves. Since the movement of the cilia is always toward the outside, they move the interfering matter upward, away from the delicate lung tissues, so that it can be expectorated or swallowed. Particles that are too large for the cilia to dispose of usually stimulate a sneeze or a cough, which forcibly expels them. Sneezing and coughing are reflex acts in response to stimulation of nerve endings in the respiratory passages. The stimulus for a cough comes from the air passages in the throat; for a sneeze, from those in the nose.
abdominal respiration inspiration accomplished mainly by the diaphragm.
oxidative transformation of certain substrates into high-energy chemical compounds; see also adenosine triphosphate
Biot's respiration breathing characterized by irregular periods of apnea alternating with periods in which four or five breaths of identical depth are taken; seen in patients with increased intracranial pressure associated with spinal meningitis and other central nervous system disorders.
cogwheel respiration breathing with jerky inhalation.
diaphragmatic respiration that performed mainly by the diaphragm.
external respiration the exchange of gases between the lungs and the blood.
internal respiration the exchange of gases between the body cells and the blood.
a distressing, paroxysmal dyspnea affecting both inspiration and expiration, characterized by increased respiratory rate (above 20 per minute), increased depth of respiration, panting, and labored respiration; seen in diabetic acidosis and coma and renal failure. Called also air hunger
in the omaha system
, a client problem
in the physiologic domain
, defined as the exchange of oxygen and carbon dioxide in the body.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
1. A fundamental process of life, characteristic of both plants and animals, in which oxygen is used to oxidize organic fuel molecules, providing a source of energy as well as carbon dioxide and water. In green plants, photosynthesis is not considered respiration
[L. respiratio, fr. respiro, pp. -atus, to exhale, breathe]
Farlex Partner Medical Dictionary © Farlex 2012
a. The action or process of inhaling and exhaling; breathing. Also called ventilation.
b. An act of inhaling and exhaling; a breath.
2. The action or process by which an organism without lungs, such as a fish or plant, exchanges gases with its environment.
a. The oxidative process occurring within living cells by which the chemical energy of organic molecules is converted in a series of metabolic steps into usable energy in the form of ATP, involving the consumption of oxygen and the production of carbon dioxide and water as byproducts.
b. Any of various analogous metabolic processes by which certain organisms, such as anaerobic bacteria and some fungi, obtain energy from organic molecules without consuming oxygen.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.
respiration Breathing; to inhale and exhale; the exchange of gases between the external environment and an organism's cells. See Anaerobic respiration, Cellular respiration, Cheyne-Stokes respiration.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.
1. A fundamental process of life, characteristic of both plants and animals, in which oxygen is used to oxidize organic fuel molecules, providing a source of energy as well as carbon dioxide and water. In green plants, photosynthesis is not considered respiration.
[L. respiratio, fr. respiro, pp. -atus, to exhale, breathe]
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
respiration (res?pi-ra'shon ) [L. respiratio, breathing]
1. The interchange of gases between an organism and the medium in which it lives.
MUSCLES OF RESPIRATION
The act of breathing (inhaling and exhaling) during which the lungs are provided with air through inhaling and the carbon dioxide is removed through exhaling. Normal respiratory exchange of oxygen and carbon dioxide in the lungs is impossible unless the pulmonary tissue is adequately perfused with blood. See: lung
Respiration in which chiefly the diaphragm exerts itself while the chest wall muscles are nearly at rest; used in normal, quiet breathing, and in pathological conditions such as pleurisy, pericarditis, and rib fracture. Synonym: belly breathing
; diaphragmatic respiration
Respiration in which respiratory sounds are suppressed or absent.
Cellular respiration in which oxygen is used in the production of energy.
Respiration having amphoric resonance. See: amphoric resonance
The release of energy from the reduction of metals (such as iron, manganese, or sulfur) by cells or organisms that do not use oxygen as their primary energy source.
Breathing marked by prolonged inspiration unrelieved by attempts to exhale. It is seen in patients who have had the upper part of the pons of the brain removed or damaged.
Maintenance of respiratory movement by artificial means, such as rescue breathing, bag mask, pocket mask, automatic transport ventilator, manual transport ventilator, or a flow-restricted oxygen-powered ventilation device. See: cardiopulmonary resuscitation
Biot respirationBiot breathing.
Bouchut respiration See: Bouchut respiration
The gradual breakdown of food molecules in the presence of oxygen within cells, resulting in the formation of carbon dioxide and water and the release of energy in the forms of adenosine triphosphate and heat. In many intermediary reactions, substances other than oxygen act as oxidizing agents (hydrogen or electron acceptors). Reactions are catalyzed by respiratory enzymes, which include the flavoproteins, cytochromes, and other enzymes. Certain vitamins (nicotinamide, riboflavin, thiamine, pyridoxine, and pantothenic acid) are essential in the formation of components of various intracellular enzyme systems.
Cheyne-Stokes respiration See: Cheyne-Stokes respiration
cogwheel respirationInterrupted respiration.
Respiration in which the chest cavity expands by raising the ribs.
The transpiration of gases through the skin.
Respiration at less than a normal rate for the individual's age. In adults, it is a respiratory rate of less than 12 breaths per minute. Slower than normal respiratory rates occur after opiate or sedative use, during sleep, in coma, and other conditions and may result in respiratory failure or carbon dioxide retention. Synonym: slow respiration
diaphragmatic respirationAbdominal respiration.
Respiration in which an organism, such as a one-celled ameba, secures its oxygen and gives up carbon dioxide directly to the surrounding medium.
electrophrenic respirationRadiofrequency electrophrenic respiration.
The exchange of gases in the lungs. Oxygen diffuses from the air to the blood, and carbon dioxide diffuses from the blood to the air. See: gas exchange
Gas exchange in the placenta between the fetal and maternal blood. Synonym: placental respiration
The exchange of gases in body tissues. Oxygen diffuses from the blood to the cells, and carbon dioxide diffuses from the cells to the blood. Oxygen is carried in combination with hemoglobin. Oxyhemoglobin gives arterial blood its red color; reduced hemoglobin gives venous blood its dark red color. Most carbon dioxide is carried in the blood as bicarbonate ions; a small amount is bonded to hemoglobin. Normally the partial pressure of oxygen in the blood is 75 to 100 mm Hg, depending on age; for carbon dioxide it is 35 to 45 mm Hg. Synonym: tissue respiration See: gas exchange
Respiration in which inspiratory or expiratory sounds are not continuous. Synonym: cogwheel respiration
Respiration by the fetus before birth. See: fetal respiration
Kussmaul respiration See: Kussmaul, Adolph
Respiration that involves active participation of accessory inspiratory and expiratory muscles; dyspnea.
The stages of cell respiration (citric acid cycle and cytochrome transport system) that take place in the mitochondria. Water is formed from oxygen and hydrogen ions, and energy is released. See: cell respiration
1. Respiration occurring in patients with chest trauma and multiple rib fractures in which a portion of the chest wall sinks inward with each spontaneous inspiratory effort.
2. A condition seen in paralysis of the diaphragm in which the diaphragm ascends during inspiration.
periodic respirationPeriodic breathing.
placental respirationFetal respiration.
radiofrequency electrophrenic respiration
A method of stimulating respiration in cases of respiratory paralysis from spinal cord injury at the cervical level. Intermittent electrical stimuli to the phrenic nerves are supplied by a radiofrequency transmitter implanted subcutaneously. The diaphragmatic muscles contract in response to these stimuli.
slow respirationDecreased respiration.
Respiration marked by high-pitched crowing or barking sound heard on inspiration, caused by an obstruction near the glottis or in the respiratory passageway.
Respiration performed entirely by expansion of the chest when the abdomen does not move. It is seen when the peritoneum or diaphragm is inflamed, when the abdominal cavity is restricted by tight bandages or clothes, or during abdominal surgery. See: Thoracic Spine and Rib Cage Breathing
tissue respirationInternal respiration.
Increased respiration in one lung when respiration in the other is lessened or abolished.
Medical Dictionary, © 2009 Farlex and Partners
The whole process by which oxygen is transferred from the atmosphere to the body cells and carbon dioxide is moved from the cells to the atmosphere. Respiration is vital to life and cessation for more than a few minutes is fatal. See also CHEYNE-STOKES RESPIRATION
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005
Respiration is the process by which nutrients (specifically sugar, or glucose) and oxygen are taken in to a cell; chemical reactions take place; energy is produce and stored; and carbon dioxide and wastes are given off.
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.
1. Fundamental process of life, characteristic of both plants and animals, in which oxygen is used to oxidize organic fuel molecules, providing a source of energy as well as carbon dioxide and water. In green plants, photosynthesis is not considered respiration
[L. respiratio, fr. respiro, pp. -atus, to exhale, breathe]
Medical Dictionary for the Dental Professions © Farlex 2012
Patient discussion about respiration
Q. Help her to breathe. My sixteen year old cousin (girl) who is wondering if she is suffering from asthma, anxiety or both. She is thin, healthy girl and have been very worried She have asthma and have been thinking about it constantly. When she exercise, she get more out of breath, more worn out, and her heart beats faster than other people. Sometimes her chest hurts, but people tell me that is from my chest muscles being worked. She get a little dizzy also. When she go to bed at night sometimes it seems hard to breathe. She can take a deep breath and everything but it seems hard or something. I know there isn't anything wrong with my heart because she had an EKG done recently and chest x-rays. That was fine. When it is hot humid and muggy outside she find it hard to breath. Do you think she have asthma. She don't have any coughing or any known wheezing. Could thinking about every breath she take seem like she have asthma? She really want to know and me too, what is going on! Please help her to breathe!!!!
A. PS--alcohol and cigarettes can cause this problem to(drugs)mrfoot56.
Q. What causes bad breath? I have bad breath for a long time. What causes it?
A. Here are some causes of bad breath:
A Dry mouth- Saliva helps cleanse and moisten your mouth. A dry mouth enables dead cells to accumulate on your tongue, gums and cheeks. These cells then decompose and cause odor. Dry mouth naturally occurs during sleep. It's what causes "morning breath." Dry mouth is even more of a problem if you sleep with your mouth open. Some medications as well as smoking can lead to a chronic dry mouth, as can a problem with your salivary glands.
Some Diseases can also cause bad breath- Chronic lung infections and lung abscesses can produce very foul-smelling breath. Other illnesses, such as some cancers and certain metabolic disorders, can cause a distinctive breath odor. Kidney failure can cause a urine-like odor, and liver failure may cause an odor described as "fishy." People with uncontrolled diabetes often have a fruity breath odor. Chronic reflux of stomach acids from your stomach (gastroesophageal reflux disease, or GERD)
Q. How to get rid of bad breath? My wife complains that I have bad breath. How can I get rid of it?
A. Consider that candida infection can make your breath worse. You might try cutting down on sugar and carbs.More discussions about respiration
"Bad breath can also be caused by a candida (yeast infection), you may have a constant white furry tongue. Look at cutting down your intake of sugars and processed foods, as well as those containing yeast. - Search for Anti-Candida diet on a search engine for more info"
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