Home About us Contact
|
Home About us Contact | ||
|
|
||
Respiratory Unit (respiratory + unit)
Selected AbstractsRespiratory units of motor production and song imitation in the zebra finchDEVELOPMENTAL NEUROBIOLOGY, Issue 2 2002Michele Franz Abstract Juvenile male zebra finches (Taeniopygia guttata) learn a stereotyped song by imitating sounds from adult male tutors. Their song is composed of a series of syllables, which are separated by silent periods. How acoustic units of song are translated into respiratory and syringeal motor gestures during the song learning process is not well understood. To learn about the respiratory contribution to the imitation process, we recorded air sac pressure in 38 male zebra finches and compared the acoustic structures and air sac pressure patterns of similar syllables qualitatively and quantitatively. Acoustic syllables correspond to expiratory pressure pulses and most often (74%) entire syllables are copied using similar air sac pressure patterns. Even notes placed within different syllables are generated with similar air sac pressure patterns when only segments of syllables are copied (9%). A few of the similar syllables (17%) are generated with a modified pressure pattern, typically involving addition or deletion of an inspiration. The high similarity of pressure patterns for like syllables indicates that generation of particular sounds is constrained to a narrow range of air sac pressure conditions. Following presentation of stroboscope flashes, song was typically interrupted at the end of an expiratory pressure pulse, confirming that expirations and, therefore, syllables are the smallest unit of motor production of song. Silent periods, which separate syllables acoustically, are generated by switching from expiration to inspiration. Switching between respiratory phases, therefore, appears to play a dominant role in organizing the stereotyped motor program for song production. © 2002 Wiley Periodicals, Inc. J Neurobiol 51: 129,141, 2002 [source] Effects of fetal growth restriction on lung development before and after birth: A morphometric analysisPEDIATRIC PULMONOLOGY, Issue 3 2001G.S. Maritz PhD Abstract Our aim was to determine the effects of fetal growth restriction (FGR) during late gestation on the structure of the lungs in the fetus near term and at 8 weeks after birth. The studies were performed using two groups of pregnant sheep and their offspring. In both groups, FGR was induced by umbilico-placental embolisation (UPE); for fetal studies, UPE was performed from 120 days of gestation until 140 days (term, ,146 days), when fetuses were killed for tissue analysis. For postnatal studies, UPE continued from 120 days until delivery at term; postnatal lambs were killed at 8 weeks after birth for tissue analysis. UPE led to a thicker pulmonary blood-air barrier at 140 days of gestation and this difference, which was due to a thickened basement membrane, was still present at 8 weeks after birth. At 8 weeks, we also observed a smaller number of alveoli per respiratory unit, thicker interalveolar septa, and a greater volume density of lung tissue in FGR lambs compared to controls. These changes would be expected to impair gas exchange and alter the mechanical properties of the lungs. Our data show that structural alterations in the lungs induced by placental insufficiency were more evident at 8 weeks of postnatal age than near term, indicating that the effects of FGR on the lung may become more serious with age and may affect respiratory health later in life. Pediatr Pulmonol. 2001; 32:201,210. © 2001 Wiley-Liss, Inc. [source] Bullous lung disease due to marijuanaRESPIROLOGY, Issue 1 2008Su W. HII Background and objective: In contrast to the well-described effects of tobacco smoking upon pulmonary emphysema, with ,15% of smokers being affected at the age of 65 years, the effects of marijuana smoking are rarely reported and poorly understood. Methods: We report a series of 10 patients (mean age 41 ± 9 years, eight male, two female), who presented over a period of 12 months to our respiratory unit with new respiratory symptoms, and who admitted to regular chronic marijuana smoking (>1 year continuously). Symptoms on presentation were dyspnoea (n = 4), pneumothorax (n = 4) and chest infection (n = 2). Results: High-resolution CT revealed asymmetrical, variably sized, emphysematous bullae in the upper and mid zones. However, the CXR was normal in four patients and lung function was normal in five. Conclusions: Marijuana smoking leads to asymmetrical bullous disease, often in the setting of normal CXR and lung function. In subjects who smoke marijuana, these pathological changes occur at a younger age (approximately 20 years earlier) than in tobacco smokers. [source] Three-Dimensional Serial Section Computer Reconstruction of the Arrangement of the Structural Components of the Parabronchus of the Ostrich, Struthio Camelus LungTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 11 2009John N. Maina ,Cubed' three-dimensional computer reconstruction (from serial sections) of the exchange tissue (parenchyma) of the lung of the ostrich, Struthio camelus showing the profuse anastomoses of the air capillaries (shown in cyan) and the blood capillaries (shown in red). While the two terminal respiratory units interdigitate very copiously as they interface intimately, thereby optimizing the respiratory surface area, regarding their size and shape, they are not mirror images as has previously been reported nor do they spatially form a counter-current arrangement, as they have been commonly modelled. See Maina et al., "Three-Dimensional Serial Section Computer Reconstruction of the Arrangement of the Structural Components of the Parabronchus of the Ostrich, Struthio Camelus Lung," on page 1685, in this issue. [source] | |||||||||||||