Respiratory physiology

Hemoglobin (haemoglobin, Hb or Hgb) is a protein containing iron that facilitates the transportation of oxygen in red blood cells. Almost all vertebrates contain hemoglobin, with the sole exception of the fish family Channichthyidae. Hemoglobin in the blood carries oxygen from the respiratory organs (lungs or gills) to the other tissues of the body, where it releases the oxygen to enable aerobic respiration which powers an animal's metabolism. A healthy human has 12to 20grams of hemoglobin in every 100mL of blood. Hemoglobin is a metalloprotein, a chromoprotein, and a globulin.

human disease

the portion of the cardiovascular system which carries deoxygenated blood away from the heart, to the lungs, and returns oxygenated blood back to the heart

maximum rate of oxygen consumption as measured during incremental exercise, most typically on a motorized treadmill

thumb|right|Doing spirometry Spirometry (meaning the measuring of breath) is the most common of the pulmonary function tests (PFTs). It measures lung function, specifically the amount (volume) and/or speed (flow) of air that can be inhaled and exhaled. Spirometry is helpful in assessing breathing patterns that identify conditions such as asthma, pulmonary fibrosis, cystic fibrosis, and COPD. It is also helpful as part of a system of health surveillance, in which breathing patterns are measured over time.

thumb|Diagram showing inhalation Inhalation (or inspiration) happens when air or other gases enter the lungs.

A bronchodilator or broncholytic (although the latter occasionally includes secretory inhibition as well) is a substance that dilates the bronchi and bronchioles, decreasing resistance in the respiratory airway and increasing airflow to the lungs. Bronchodilators may be originating naturally within the body, or they may be medications administered for the treatment of breathing difficulties, usually in the form of inhalers. They are most useful in obstructive lung diseases, of which asthma and chronic obstructive pulmonary disease are the most common conditions. They may be useful in bronchiol

Hypoxemia (also spelled hypoxaemia) is an abnormally low level of oxygen in the blood. More specifically, it is oxygen deficiency in arterial blood. Hypoxemia is usually caused by pulmonary disease. Sometimes the concentration of oxygen in the air is decreased leading to hypoxemia.

thumb|Diagram showing expiration Exhalation (or expiration) is the flow of the breath out of an organism. In animals, it is the movement of air from the lungs out of the airways, to the external environment during breathing. This happens due to elastic properties of the lungs, as well as the internal intercostal muscles which lower the rib cage and decrease thoracic volume. As the thoracic diaphragm relaxes during exhalation it causes the tissue it has depressed to rise superiorly and put pressure on the lungs to expel the air. During forced exhalation, as when blowing out a candle, expiratory

thumbnail|right|The structure of cytochrome b5 reductase, the enzyme that converts methemoglobin to hemoglobin.

shift in the oxygen dissociation curve caused by changes in the concentration of carbon dioxide or the pH of the environment

measurements of the volume of air in the lungs

A chemoreceptor, also known as chemosensor, is a specialized sensory receptor which transduces a chemical substance (endogenous or induced) to generate a biological signal. This signal may be in the form of an action potential, if the chemoreceptor is a neuron, or in the form of a neurotransmitter that can activate a nerve fiber if the chemoreceptor is a specialized cell, such as taste receptors, or an internal peripheral chemoreceptor, such as the carotid bodies. In physiology, a chemoreceptor detects changes in the normal environment, such as an increase in blood levels of carbon dioxide (hy

thumb|upright|A Charles Lindbergh|Lindbergh perfusion pump, , an early device for simulating natural perfusion

test of blood taken from an artery that measures the amounts of certain dissolved gases

lipoprotein complex

maximum amount of air a person can expel from the lungs after a maximum inhalation

groupe of stereoisomers

breathing frequency; rate at which breathing occurs. This is usually measured in breaths per minute

Carboxyhemoglobin (carboxyhaemoglobin BrE) (symbol COHb or HbCO, also known as carbonylhemoglobin) is a stable complex of carbon monoxide and hemoglobin (Hb) that forms in red blood cells upon contact with carbon monoxide. Carboxyhemoglobin is often mistaken for the compound formed by the combination of carbon dioxide (carboxyl) and hemoglobin, which is actually carbaminohemoglobin. Carboxyhemoglobin terminology emerged when carbon monoxide was known by its historic name, "carbonic oxide", and evolved through Germanic and British English etymological influences; the preferred IUPAC nomenclatur

Deoxygenated blood increases the capacity for carbon dioxide transport

volume of air displaced between normal inhalation and exhalation

air that does not take part in gas exchange

Scientific phenomenon

thumb|Illustration depicting bronchoconstriction (Asthma) Bronchoconstriction is the constriction of the airways in the lungs due to the tightening of surrounding smooth muscle, with consequent coughing, wheezing, and shortness of breath.

breathing control

macrophage found in the pulmonary alveolus

ratio of volume change per pressure change in the lung

Biological reflex to prevent lung over-inflation

term in medicine

ability of a biological organ to distend

measurement representing the ratio of carbon dioxide produced by the body to oxygen consumed by the body

S-shaped curve produced when the percentage saturation of haemoglobin with oxygen is plotted against the partial pressure of oxygen (pO2), which is a measure of the oxygen concentration in the surrounding medium

ratio used in the diagnosis of lung disease

organisms capable of living at high altitudes

quantity of a gas taken up, by the pulmonary capillary blood from the alveolar gas, per minute per unit of average pressure of the gradient of the gas

volume of air in the lungs at the end of passive expiration

bypass of the pulmonary capillaries by deoxygenated blood

loss of consciousness caused by cerebral hypoxia towards the end of a breath-hold dive

respiratory parameter for differential diagnosis of hypoxemia

lung function test measuring effect of pressure oscillation on airflow

shift of chloride ion inside RBC due to movement of bicarbonate ion outside

protein-coding gene in the species Homo sapiens

physiological phenomenon in fish hemoglobin

Chemical reaction making 2,3-BPG

evolutionary adaptation of some poulations