Inhalation (also known as inspiration ) is the movement of air from the external environment, through the air ways, and into the alveoli An alveolus is an anatomical structure that has the form of a hollow cavity. Found in the lung, the pulmonary alveoli are spherical outcroppings of the respiratory sites of gas exchange with the blood. Alveoli are particular to mammalian lungs. Different structures are involved in gas exchange in other vertebrates. The alveolar membrane is the gas- .
Inhalation begins with the onset of contraction of the diaphragm In the anatomy of mammals, the thoracic diaphragm or sometime simply, the diaphragm, is a sheet of internal muscle that extends across the bottom of the rib cage. The diaphragm separates the thoracic cavity from the abdominal cavity and performs an important function in respiration. A diaphragm in anatomy can refer to other flat structures such as , which results in expansion of the intrapleural space and an increase in negative pressure according to Boyle's Law Boyle's law is one of several gas laws and a special case of the ideal gas law. Boyle's law describes the inversely proportional relationship between the absolute pressure and volume of a gas, if the temperature is kept constant within a closed system. The law was named after chemist and physicist Robert Boyle, who published the original law in 166 . These negative pressure generates airflow because of the pressure difference between the atmosphere and alveolus. Air enters, inflating the lung through either the nose Physically a nose is an organ on the face. Anatomically, a nose is a protuberance in vertebrates that houses the nostrils, or nares, which admit and expel air for respiration in conjunction with the mouth. Behind the nose is the olfactory mucosa and the sinuses. Behind the nasal cavity, air next passes through the pharynx, shared with the or the mouth The mouth is the first portion of the alimentary canal that receives food and begins digestion by mechanically breaking up the solid food particles into smaller pieces and mixing them with saliva. The oral mucosa is the mucous membrane epithelium lining the inside of the mouth into the pharynx The pharynx is the part of the neck and throat situated immediately posterior to (behind) the mouth and nasal cavity, and cranial, or superior, to the esophagus, larynx, and trachea (throat In vertebrate anatomy, the throat is the anterior part of the neck, in front of the vertebral column. It consists of the pharynx and larynx. An important feature of the throat is the epiglottis, a flap which separates the esophagus from the trachea and prevents inhalation of food or drink ) and trachea The trachea, or windpipe, is a tube that connects to the pharynx or larynx, allowing the passage of air to the lungs. It is lined with pseudostratified ciliated columnar epithelium cells with mucosal goblet cells which produce mucus. This mucus lines the cells of the trachea to trap inhaled foreign particles which the cilia then waft upwards before entering the alveoli.
Other muscles that can be involved in inhalation include[1]
Hyperaeration
Lungs and breathing activity
Bradypnea Bradypnea , British English spelling bradypnoea refers to an abnormally slow breathing rate. The rate at which bradypnea is diagnosed depends upon the age of the patient - decreased breathing rate
Dyspnea Dyspnea or dyspnoea , (from Latin dyspnoea, from Greek dyspnoia from dyspnoos, shortness of breath), also called shortness of breath (SOB) or air hunger, is a debilitating symptom that is the experience of unpleasant or uncomfortable respiratory sensations. It is a common symptom of numerous medical disorders, particularly those involving the or shortness of breath - sensation of respiratory distress
Eupnea - normal breathing
Hyperaeration /Hyperinflation - increased lung volume
Hyperpnea Hyperpnea is increased depth of breathing when required to meet demand, as during or following exercise or when the body lacks oxygen , for instance in high altitude or as a result of anaemia - faster and/or deeper breathing
Hyperventilation In medicine, hyperventilation is the state of breathing faster and/or deeper than necessary. It can result from a psychological state such as a panic attack, from a physiological condition such as metabolic acidosis, or can be brought about voluntarily - increased breathing that causes CO2 loss
Labored breathing - physical presentation of respiratory distress
Tachypnea It is not identical with hyperventilation - tachypnea may be necessary for a sufficient gas-exchange of the body, for example after exercise, in which case it is not hyperventilation - increased breathing rate
Hyperaeration or hyperinflation is where the lung volume is abnormally increased, with increased filling of the alveoli. This results in an increased radiolucency Radiodensity is the property of relative transparency to the passage of X-rays through a material. Radiolucent indicates greater transparency or "transradiancy" to X-ray photons.:4 Radiodense indicates greater opacity to X-ray photons on X-ray, a reduction in lung markings and depression of the diaphragm. It may occur in partial obstruction of a large airway, as in e.g. congenital lobar emphysema , bronchial atresia and mucous plugs in asthma Asthma is a common chronic inflammatory disease of the airways characterized by variable and recurring symptoms, airflow obstruction, and bronchospasm. Symptoms include wheezing, coughing, chest tightness, and shortness of breath .[2]
It causes one form of overexpansion of the lung. Overexpansion, however, can also be caused by increase in lung mass itself.
See also
References
^ Physiology at MCG The Medical College of Georgia, also known as MCG, is a public medical research university located in downtown Augusta, Georgia. It is the state's only health sciences university. The university has five schools: Schools of Allied Health Sciences, Dentistry, Graduate Studies, Medicine and Nursing. Its mission is to improve health and reduce the 4/4ch2/s4ch2_10 ^ Hyperinflation medcyclopaedia.com --> Hyperinflation] Retrieved on June 5, 2009
Respiratory system The respiratory system's function is to allow oxygen exchange through all parts of the body. The space between the alveoli and the capillaries, the anatomy or structure of the exchange system, and the precise physiological uses of the exchanged gases vary depending on organism. In humans and other mammals, for example, the anatomical features of , physiology Human physiology is the science of the mechanical, physical, and biochemical functions of humans in good health, their organs, and the cells of which they are composed. The principal level of focus of physiology is at the level of organs and systems. Most aspects of human physiology are closely homologous to corresponding aspects of animal : respiratory physiology Where Pel equals the product of elastance E and volume of the system V, Pre equals the product of flow resistance R and time derivate of volume V (which is equivalent to the flow), Pin equals the product of inertance I and second time derivate of V. R and I are sometimes referred to as Rohrer's constants
Lung volumes The average lung of human lungs can hold about 6 litres of air, but only a small amount of this capacity is used during normal breathing
VC A person's vital capacity can be measured by a spirometer which can be a wet or regular spirometer. In combination with other physiological measurements, the vital capacity can help make a diagnosis of underlying lung disease. The unit that is used to determine this vital capacity is millilitres · FRC Functional Residual Capacity is the volume of air present in the lungs at the end of passive expiration. At FRC, the elastic recoil forces of the lungs and chest wall are equal but opposite and there is no exertion by the diaphragm or other respiratory muscles · Vt Tidal volume is the lung volume representing the normal volume of air displaced between normal inspiration and expiration when extra effort is not applied. Typical values are around 500ml or 7ml/kg bodyweight · dead space In physiology, dead space is air that is inhaled by the body in breathing, but does not take part in gas exchange. Not all the air in each breath is able to be used for the exchange of oxygen and carbon dioxide. About a third of every resting breath is exhaled exactly as it came into the body. In adults, it is usually in the range of 150 mL · CC The closing capacity is the volume in the lungs at which its smallest airways, the alveoli collapse. The alveoli lack supporting cartilage and so depend on other factors to keep them open. The closing capacity is usually less than the residual volume (RV), the amount of gas that normally remains in the lungs during respiration. This means that
calculations: respiratory minute volume Respiratory minute volume is the volume of air which can be inhaled (inhaled minute volume) or exhaled (exhaled minute volume) from a person's lungs in one minute. This is normally registered when a person has a ventilator supporting the person's breathing due to a sickness or injury · FEV1/FVC ratio The FEV1/FVC ratio is a calculated ratio used in the diagnosis of obstructive and restrictive lung disease
devices: spirometry Spirometry is the most common of the Pulmonary Function Tests (PFTs), measuring lung function, specifically the measurement of the amount (volume) and/or speed (flow) of air that can be inhaled and exhaled. Spirometry is an important tool used for generating pneumotachographs which are helpful in assessing conditions such as asthma, pulmonary · body plethysmography Body plethysmography is a very sensitive lung measurement used to detect lung pathology that might be missed with conventional pulmonary function tests. This method of obtaining the absolute volume of air within one's lungs may also be used in situations where several repeated trials are required or where the patient is unable to perform the · peak flow meter A peak flow meter is a small, hand-held device used to monitor a person's ability to breathe out air. It measures the airflow through the bronchi and thus the degree of obstruction in the airways
Airways/
ventilation (V) In respiratory physiology, ventilation is the rate at which gas enters or leaves the lung. It is categorised under the following definitions:
positive pressure ventilation In emergency medicine positive pressure ventilation refers to the process of forcing air into the lungs of a (usually apneic or dyspneic) patient, usually using a bag valve mask (BVM) or mechanical ventilator · breath Breathing is the process that takes oxygen in and carbon dioxide in and then out of the lungs. Aerobic organisms require oxygen to release energy via respiration, in the form of the metabolism of energy-rich molecules such as glucose. The medical term for normal relaxed breathing is eupnea (inhalation , exhalation Exhalation is the movement of air out of the bronchial tubes, through the airways, to the external environment during breathing ) · respiratory rate Respiratory rate (aka respiration rate, pulmonary ventilation rate or ventilation rate) is the number of breaths a living being, such as a human, takes within a certain amount of time (frequently given in breaths per minute) · respirometer A respirometer is a device used to measure the rate of respiration of a living organism by measuring its rate of exchange of oxygen and/or carbon dioxide. They allow investigation into how factors such as age, chemicals or the effect of light affect the rate of respiration. Respirometers are designed to measure respiration either on the level of a · pulmonary surfactant Pulmonary surfactant is a surface-active lipoprotein complex formed by type II alveolar cells. The proteins and lipids that surfactant comprises have both a hydrophilic region and a hydrophobic region. By adsorbing to the air-water interface of alveoli with the hydrophilic headgroups in the water and the hydrophobic tails facing towards the air, · compliance Pulmonary compliance is the ability of the lungs to stretch during a change in volume relative to an applied change in pressure · hysteresivity Hysteresivity derives from “hysteresis”, meaning “lag”. It is the tendency to react slowly to an outside force, or to not return completely to its original state. Whereas the area within a hysteresis loop represents energy dissipated to heat and is an extensive quantity with units of energy, the hysteresivity represents the fraction of the · airway resistance Airway resistance is a concept used in respiratory physiology to describe mechanical factors which limit the access of inspired air to the pulmonary alveoli, and thus determine airflow · bronchial hyperresponsiveness Bronchial hyperresponsiveness is a state characterised by easily triggered bronchospasm (contraction of the bronchioles or small airways) · bronchial challenge test A bronchial challenge test is a medical test used to assist in the diagnosis of asthma. The patient breathes in nebulized methacholine or histamine. Thus the test may also be called a methacholine challenge test or histamine challenge test respectively. Both drugs provoke bronchoconstriction, or narrowing of the airways. The degree of narrowing · bronchoconstriction Bronchoconstriction is the constriction of the airways in the lungs due to the tightening of surrounding fibdh, with consequent coughing, wheezing, and shortness of breath. Bronchoconstriction can also be due to an accumulation of thick mucus /bronchodilation
Blood/
perfusion (Q)
pulmonary circulation · hypoxic pulmonary vasoconstriction · pulmonary shunt
Interactions/
ventilation/perfusion ratio (V/Q)
ventilation/perfusion scan · zones of the lung · gas exchange · pulmonary gas pressures · alveolar gas equation · alveolar-arterial gradient · hemoglobin · oxygen-haemoglobin dissociation curve (2,3-DPG , Bohr effect , Haldane effect ) · carbonic anhydrase (chloride shift ) · oxyhemoglobin · respiratory quotient · arterial blood gas · diffusion capacity (DLCO )
Control of respiration
pons pneumotaxic center , apneustic center ) · medulla dorsal respiratory group , ventral respiratory group ) · chemoreceptors central , peripheral ) · pulmonary stretch receptors (Hering-Breuer reflex )
Insufficiency
high altitude · oxygen toxicity · hypoxia
: RES
anat(,,,)//
()//, /,
, drug(/////)
Categories: Respiration | Respiratory physiology
Personal tools
New features
Log in / create account
Namespaces
">
Variants
Views
">
Actions
Search"> Search Navigation
Interaction
About Wikipedia
Community portal
Recent changes
Contact Wikipedia
Donate to Wikipedia
Help
Toolbox
What links here
Related changes
Upload file
Special pages
Permanent link
Cite this page
Print/export
Create a book Download as PDF Printable version Languages
العربية
Català
Deutsch
Español
Esperanto
Français
Nederlands
日本語
Norsk (bokmål)
Polski
Português
Русский
Simple English
Türkmençe
Українська
中文