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a membranous fold in a canal or passage that prevents backward flow of material passing through it.
aortic valve a semilunar valve that separates the left ventricle and the aorta; it opens with end diastole, causing the second heart sound.
atrioventricular v's the cardiac valves between the right atrium and right ventricle (tricuspid valve) and the left atrium and left ventricle (mitral valve).
bicuspid valve mitral valve.
bicuspid aortic valve a congenital anomaly of the aortic valve, caused by incomplete separation of two of the three cusps; it is generally asymptomatic early in life but is predisposed to calcification and stenosis later on.
Braschi valve a one-way valve put into the inspiratory limb of a ventilator circuit in order to measure the intrinsic positive end-expiratory pressure.
cardiac v's valves that control flow of blood through and from the heart.
coronary valve a valve at the entrance of the coronary sinus into the right atrium.
flail mitral valve a mitral valve having a cusp that has lost its normal support (as in ruptured chordae tendineae) and flutters in the blood stream.
heart v's cardiac valves.
Heimlich valve a small one-way valve used for chest drainage, emptying into a flexible collection device; the valve prevents return of gases or fluids into the pleural space. The Heimlich valve is less than 13 cm (5 inches) long and facilitates patient ambulation; it can be used in many patients instead of a traditional water seal drainage system.
ileocecal valve (ileocolic valve) the valve guarding the opening between the ileum and cecum.
mitral valve the cardiac valve between the left atrium and left ventricle, usually having two cusps (anterior and posterior). Called also bicuspid valve.
posterior urethral valve any of various types of congenital folds across the proximal part of the male urethra near the seminal colliculus, the most common cause of urethral obstruction in male infants.
pulmonary valve (pulmonic valve) the pocketlike cardiac valve that protects the orifice between the right ventricle and the pulmonary artery.
pyloric valve a prominent fold of mucous membrane at the pyloric orifice of the stomach.
thebesian valve coronary valve.
tricuspid valve the cardiac valve guarding the opening between the right atrium and right ventricle.
valve of vein (venous v's) any of the small cusps or folds found in the tunica intima of many veins, serving to prevent backflow of blood.
the valve at the entrance to the pulmonary trunk from the right ventricle; it consists of semilunar cusps (valvules), which are usually arranged in the adult in right anterior, left anterior, and posterior positions; however, they are named in accordance with their embryonic derivation; thus the posteriorly located cusp is designated as the left cusp, the right anteriorly located cusp is designated the right cusp, and the left anteriorly positioned cusp is called the anterior cusp.
a cardiac structure composed of three semilunar cusps that close during each heartbeat to prevent blood from flowing back into the right ventricle from the pulmonary trunk. The cusps are separated by sinuses that resemble tiny buckets when they are closed and filled with blood. These flaps grow from the lining of the pulmonary trunk. When they collapse from the ejection of ventricular blood, they open the valve and allow deoxygenated blood to flow through the pulmonary artery and on to the lungs. Compare aortic valve, mitral valve, tricuspid valve.
pul·mo·nar·y valve(pul'mŏ-nar-ē valv) [TA]
The valve at the entrance to the pulmonary trunk from the right ventricle; it consists of semilunar cusps (valvules) that are usually arranged in the adult in right anterior, left anterior, and posterior positions; however, they are named in accordance with their embryonic derivation; the posteriorly located cusp is designated as the left cusp, the right anteriorly located cusp is designated the right cusp, and the left anteriorly positioned cusp is called the anterior cusp.
The heart valve which is positioned between the right ventricle and the opening into the pulmonary artery.
pertaining to the lungs, or to the pulmonary artery. See also lung.
basic structural unit of the lung parenchyma; the gas exchange unit, supplied by a single terminal bronchiole and includes branches of the terminal bronchiole, alveolar ducts, alveolar sacs, alveoli and associated blood vessels. A pulmonary lobule consists of many acini.
incompatible with life; found only in fetal or neonatal necropsy specimens.
pulmonary alveolar microlithiasis
see microlithiasis alveolaris pulmonum.
pulmonary alveolar parenchyma
include epithelial cells (pneumonocytes or pneumocytes), alveolar capillary endothelial cells, and interstitial cells (fibroblasts) and alveolar macrophages.
pulmonary alveolar proteinosis
a disease of unknown etiology marked by chronic filling of the alveoli with a proteinaceous, lipid-rich, granular material consisting of surfactant and the debris of necrotic cells.
pulmonary artery wedge pressure
see wedge pressure.
the network of capillaries in lung tissue.
see microlithiasis alveolaris pulmonum.
see bronchial calculus.
see ovine pulmonary adenomatosis (below).
the circulation of blood to and from the lungs. Deoxygenated blood from the right ventricle flows through the right and left pulmonary arteries to the right and left lung. After entering the lungs, the branches subdivide, finally emerging as capillaries which surround the alveoli and release the carbon dioxide in exchange for oxygen. The capillaries unite gradually and assume the characteristics of veins. These veins join to form the pulmonary veins, which return the oxygenated blood to the left atrium. See also circulatory system.
a measure of the ability of the lung to distend in response to pressure without disruption. Expressed as the unit volume of change in the lung per unit of pressure. Compliance or distensibility of the lung is increased in conditions such as emphysema in which the lung distends more readily, and is decreased in fibrotic conditions in which the lung distends with difficulty. See also compliance.
caused by engorgement of the pulmonary vascular bed and it may precede pulmonary edema when the intravascular fluid escapes into the parenchyma and the alveoli. There is a loss of air space and the development of respiratory embarrassment.
may be congenital or acquired, caused by trauma, parasites (Paragonimus spp.), or associated with bronchiectasis. Rarely, metastatic tumors cavitate forming cysts.
pulmonary defense mechanisms
include aerodynamic filtration in nasal cavities, sneezing, local nasal antibody, laryngeal and cough reflexes, mucociliary transport mechanisms, alveolar macrophages, systemic and local antibody systems.
an effusion of serous fluid into the pulmonary interstitial tissues and alveoli. Preceded by pulmonary congestion (see above). If the extravascular exudation is sufficiently severe a critical level of hypoxia may be reached. The breathing will then be labored, the normal breath sounds on auscultation may be absent, and a frothy nasal discharge, often blood-tinged, may appear. At this stage the animal's life is about to terminate.
obstruction of the pulmonary artery or one of its branches by an embolus. The embolus usually is a blood clot swept into circulation from a large peripheral vein.
Signs vary greatly, depending on the extent to which the lung is involved. Simple, uncomplicated embolism produces such cardiopulmonary signs as dyspnea, tachypnea, persistent cough, pleuritic pain and hemoptysis. On rare occasions the cardiopulmonary signs may be acute, occurring suddenly and quickly producing cyanosis and shock. A septic embolus can lead to local pulmonary abscess or an extension to pneumonia as in caudal vena caval syndrome. See also caudal vena caval thrombosis, pulmonary abscess (above).
pulmonary eosinophilic granulomatosis
a lesion common in heartworm disease; eosinophiles and neutrophils surround trapped microfilariae causing nodules as large as 3 inches diameter. May be preceded by lesions of allergic pneumonitis.
exercise-induced pulmonary hemorrhage
traces of blood can be found in about 60% of horses after racing. Less than 1% of these bleed from the nostrils. See also epistaxis.
pulmonary function tests
tests used to evaluate lung mechanics, gas exchange, pulmonary blood flow and blood acid-base balance. Pulmonary function testing is used to detect emphysema and chronic obstructive bronchitis at an early stage.
as distinct from hemothorax, is recognized because of a syndrome of dyspnea, increased lung density radiographically, and hemorrhagic anemia. If a large vessel ruptures into an abscess cavity there is usually a massive hemoptysis and instant death. Frothy blood-stained nasal discharge is an indication of pulmonary edema rather than of pulmonary hemorrhage. See also exercise-induced pulmonary hemorrhage (above).
pulmonary horse sickness
the predominantly pulmonary form of african horse sickness.
pulmonary hypertrophic osteoarthropathy
see hypertrophic osteopathy.
a congenital defect resulting in decreased lung development.
see pulmonary infarction, pulmonary embolus (above).
pulmonary infiltration with eosinophilia (PIE)
see pie syndrome.
includes accessory lungs, pulmonary hypoplasia, pulmonary agenesis, congenital pulmonary cysts, endodermal heteroplasia, respiratory distress syndrome, neonatal maladjustment syndrome, immotile cilia syndrome.
includes aspergillosis, mortierellosis, blastomycosis, cryptococcosis, coccidioidomycosis.
many types are recorded in all species but the prevalence is very low in food animals. A common site for metastases in companion animals. Characterized clinically by decreased exercise tolerance, progressive dyspnea, chronic cough and emaciation. Most diagnoses result from radiographic examination of the thorax for secondary growths.
neurogenic pulmonary edema
results from head trauma, central nervous system lesions and toxins, which may cause increased pulmonary blood pressure and alteration to sympathetic innervation leading to fluid leakage from vessels.
overriding pulmonary artery
see overriding pulmonary artery.
ovine pulmonary adenomatosis
a very chronic progressive pneumonia of sheep and goats caused by a retrovirus. Dyspnea, emaciation and a profuse nasal discharge are the cardinal signs, but coughing is not evident. The disease is always fatal. It is of great importance if it occurs in flocks that are housed for long periods. Characteristically the extensive lung involvement includes large areas of neoplastic tissue. Called also jaagsiekte, pulmonary carcinomatosis.
see alveologram pattern, bronchial pattern.
re-expansion pulmonary edema
edema, emphysematous bullae and serosanguinous fluid in the airways with generalized pulmonary capillary endothelial damage; associated with chronic pulmonary collapse and removal of pleural effusions or pneumothorax with rapid re-expansion.
traumatic, especially when there is rib fracture, or spontaneous due to coughing and a weak parenchyma. The most common cause of pneumothorax.
pulmonary thromboembolic disease
thromboembolism causing blockage of large sections of the pulmonary vascular bed will result in at least temporary severe dyspnea. It may also lead to right heart congestive failure, i.e. cor pulmonale.
the pocket-like structure that guards the orifice between the right ventricle and the pulmonary artery.
pulmonary valve stenosis
causes right ventricular hypertrophy and a poststenotic dilatation of the pulmonary artery. There is a systolic murmur and thrill on the left side of the chest. A common congenital defect in dogs.
the large vein (right and left branches) that carries oxygenated blood from the lungs to the left atrium of the heart.
pulmonary wedge pressure
see wedge pressure.