lung bud

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tracheal bud

the outgrowth from the caudal end of the floor of the respiratory diverticulum.

res·pi·ra·to·ry di·ver·tic·u·lum

(res'pir-ă-tōr-ē dī'vĕr-tik'yū-lŭm)
Primordial pharynx that gives rise to the epithelial lining of the respiratory tract on glands of the bronchial tree.
Synonym(s): lung bud, tracheobronchial diverticulum.

lung bud

In the embryo, a pouch that grows out of each side of the developing foregut tube beginning at stage 12 (26 days). It pushes into the primitive pleural coeloms and continues to elongate and branch to become the embryonic lung.
See also: bud


either of the two main organs of respiration, lying on either side of the heart, within the chest cavity. The lungs supply the blood with oxygen inhaled from the outside air, and they dispose of waste carbon dioxide in the exhaled air, as a part of the process of respiration. They are usually divided into lobes, the left lung has up to three (cranial, middle and caudal), while the right lung has up to four (cranial, middle, caudal and accessory). Horse lungs are least subdivided; cat and dog lungs are deeply fissured into lobes.
The lungs are made of elastic tissue filled with interlacing networks of tubes and sacs carrying air, and with blood vessels carrying blood. The bronchi, which bring air to the lungs, branch out within the lungs into many smaller tubes, the bronchioles, which culminate in clusters of tiny air sacs called alveoli, whose total runs into millions. The alveoli are surrounded by a network of capillaries. Through the thin membranes of the capillaries, the air and blood make their exchange of oxygen and carbon dioxide. See also pulmonary, respiratory.
Enlarge picture
Lung lobes. By permission from Aspinall V, O'Reilly M, Introduction to Veterinary Anatomy and Physiology, Butterworth Heinemann, 2004

accessory lung
develop from an embryonic lung bud in an abnormal site, e.g. neck, abdomen.
lung birth changes
include dilation of the alveoli and the bronchial tree, marked pulmonary vasodilation, decreased resistance to blood flow through the lungs, constriction of the ductus arteriosus, removal of fluid from the fetal bronchial tree.
lung breath sounds
see breath sounds.
lung bud
blunt end of the respiratory diverticulum which grows ventrally out of the proximal end of the foregut, then extends caudally and divides into two, forming the origins of the bronchial tree.
lung consolidation
lung-digit syndrome
an uncommon condition in cats in which a primary lung tumor metastasizes to, usually multiple, digits as well as other sites.
ectopic lung
edematous, lobulated masses of lung tissue in the abdominal or thoracic cavities or in subcutaneous sites.
lung factor
closely related ipomeanols produced in rotting sweet potatoes by the catabolic activities of the fungus Perilla frutescens and other fungi of phytoalexins in the tubers. The factor is not toxic until it is activated by pulmonary microsomal enzymes.
lung fluke
lung hilus
that part of the lung that is not covered by pleura and through which blood vessels, bronchi, nerves and lymphatics enter and leave the lung.
lung lobe torsion
occurs uncommonly in dogs and cats, most often of the right middle lobe. May occur spontaneously, following trauma, or in association with pleural effusion. Impaired venous return causes engorgement and rapid necrosis. Clinical signs include coughing and hemoptysis.
lung meridian points
acupuncture points on the lung meridian.
lung perforation
may cause lung hemorrhage, emphysema, hemothorax or pneumothorax, or any combination of these conditions.
lung puller
appliance for pulling the pluck, the heart and lungs on the trachea, out of the thorax at the abattoir.
lung puncture
see lung perforation (above).
lung Qi deficiency
in acupuncture terminology is a deficiency of Qi or energy in the lungs manifested by recurrent illness, weak cough, rapid shallow respiration, dry cracked muzzle.
lung reflexes
hering-breuer reflexes.
lung resonance
resonant sound achieved on percussion of the chest wall over normal lung.
shock lung
see shock lung.
lung sounds absent
breath sounds audible on auscultation over normal lung are absent over consolidated, neoplastic and collapsed lung.
stiff lung
one with decreased compliance.
total lung capacity
the sum of the potential air spaces in the bronchioles and the alveoli.
lung volume
see total lung capacity (above), volume.