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Lillie MA, Vogl AW, Gerard SG, Raverty S, Shadwick RE. Retia mirabilia: Protecting the cetacean brain from locomotion-generated blood pressure pulses. Science 2022; 377:1452-1456. [PMID: 36137023 DOI: 10.1126/science.abn3315] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Cetaceans have massive vascular plexuses (retia mirabilia) whose function is unknown. All cerebral blood flow passes through these retia, and we hypothesize that they protect cetacean brains from locomotion-generated pulsatile blood pressures. We propose that cetaceans have evolved a pulse-transfer mechanism that minimizes pulsatility in cerebral arterial-to-venous pressure differentials without dampening the pressure pulses themselves. We tested this hypothesis using a computational model based on morphology from 11 species and found that the large arterial capacitance in the retia, coupled with the small extravascular capacitance in the cranium and vertebral canal, could protect the cerebral vasculature from 97% of systemic pulsatility. Evolution of the retial complex in cetaceans-likely linked to the development of dorsoventral fluking-offers a distinctive solution to adverse locomotion-generated vascular pulsatility.
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Affiliation(s)
- M A Lillie
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - A W Vogl
- Life Sciences Institute and Department of Cellular & Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - S G Gerard
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - S Raverty
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada.,Animal Health Centre, Ministry of Agriculture, Abbotsford, BC, Canada
| | - R E Shadwick
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
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2
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Sierra E, Ramírez T, Bernaldo de Quirós Y, Arregui M, Mompeó B, Rivero MA, Fernández A. Pulmonary and Systemic Skeletal Muscle Embolism in a Beaked Whale with a Massive Trauma of Unknown Aetiology. Animals (Basel) 2022; 12:ani12040508. [PMID: 35203216 PMCID: PMC8868372 DOI: 10.3390/ani12040508] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 02/15/2022] [Accepted: 02/16/2022] [Indexed: 12/02/2022] Open
Abstract
Simple Summary A severe trauma of unknown aetiology was suspected as the cause of death in an adult female Sowerby’s beaked whale found floating dead in the Canary Islands in December 2016. Many bruises in the skin and muscles (contusions) were observed in the chest wall and bone fractures, mainly located in the mandible and ribs. The broken rib bones also affected thoracic muscles, which escaped into the blood circulation once ruptured, reaching several organic locations, including the lungs, where they became trapped within the small lumen of pulmonary blood vessels, leading to a systemic and pulmonary skeletal muscle embolism. An embolism occurs when a piece of intravascular internal or foreign material obstructs the lumen of a blood vessel, starving tissues of blood and oxygen. An embolism necessarily needs cardiac function, indicating a survival time after trauma. This case report aimed to include the diagnosis of skeletal muscle embolism as a routine tool to determine if the traumatic event occurred before or after death. This is especially valuable when working with dead animals because no other evidence of traumatic injury may be recorded if carcasses are in advanced decay. Abstract An adult female Sowerby’s beaked whale was found floating dead in Hermigua (La Gomera, Canary Islands, Spain) on 7 December 2016. Severe traumas of unknown aetiology were attributed, and the gross and microscopic findings are consistent with catastrophic trauma as a cause of death. Rib fractures affected the intercostals, transverse thoracis skeletal muscles, and thoracic rete mirabile. Degenerated muscle fibres were extruded to flow into vascular and lymphatic vessels travelling to several anatomic locations into the thoracic cavity, including the lungs, where they occluded the small lumen of pulmonary microvasculature. A pulmonary and systemic skeletal muscle embolism was diagnosed, constituting the first description of this kind of embolism in an animal. The only previous description has been reported in a woman after peritoneal dialysis. Skeletal pulmonary embolism should be considered a valuable diagnostic for different types of trauma in vivo in wild animals. This is especially valuable when working with decomposed carcasses, as in those cases, it is not always feasible to assess other traumatic evidence.
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Affiliation(s)
- Eva Sierra
- Division of Histology and Animal Pathology, University Institute of Animal Health and Food Security (IUSA), Universidad de Las Palmas de Gran Canaria (ULPGC), 35413 Las Palmas, Canary Islands, Spain; (E.S.); (T.R.); (Y.B.d.Q.); (M.A.); (M.A.R.)
| | - Tania Ramírez
- Division of Histology and Animal Pathology, University Institute of Animal Health and Food Security (IUSA), Universidad de Las Palmas de Gran Canaria (ULPGC), 35413 Las Palmas, Canary Islands, Spain; (E.S.); (T.R.); (Y.B.d.Q.); (M.A.); (M.A.R.)
| | - Yara Bernaldo de Quirós
- Division of Histology and Animal Pathology, University Institute of Animal Health and Food Security (IUSA), Universidad de Las Palmas de Gran Canaria (ULPGC), 35413 Las Palmas, Canary Islands, Spain; (E.S.); (T.R.); (Y.B.d.Q.); (M.A.); (M.A.R.)
| | - Marina Arregui
- Division of Histology and Animal Pathology, University Institute of Animal Health and Food Security (IUSA), Universidad de Las Palmas de Gran Canaria (ULPGC), 35413 Las Palmas, Canary Islands, Spain; (E.S.); (T.R.); (Y.B.d.Q.); (M.A.); (M.A.R.)
| | - Blanca Mompeó
- Department of Morphology, Universidad de Las Palmas de Gran Canaria (ULPGC), 35016 Las Palmas, Canary Islands, Spain;
| | - Miguel A. Rivero
- Division of Histology and Animal Pathology, University Institute of Animal Health and Food Security (IUSA), Universidad de Las Palmas de Gran Canaria (ULPGC), 35413 Las Palmas, Canary Islands, Spain; (E.S.); (T.R.); (Y.B.d.Q.); (M.A.); (M.A.R.)
| | - Antonio Fernández
- Division of Histology and Animal Pathology, University Institute of Animal Health and Food Security (IUSA), Universidad de Las Palmas de Gran Canaria (ULPGC), 35413 Las Palmas, Canary Islands, Spain; (E.S.); (T.R.); (Y.B.d.Q.); (M.A.); (M.A.R.)
- Correspondence:
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3
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Rowlands CE, McLellan WA, Rommel SA, Costidis AM, Yopak KE, Koopman HN, Glandon HL, Ann Pabst D. Comparative morphology of the spinal cord and associated vasculature in shallow versus deep diving cetaceans. J Morphol 2021; 282:1415-1431. [PMID: 34228354 DOI: 10.1002/jmor.21395] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 06/29/2021] [Accepted: 07/04/2021] [Indexed: 12/19/2022]
Abstract
The cetacean vertebral canal houses the spinal cord and arterial supply to and venous drainage from the entire central nervous system (CNS). Thus, unlike terrestrial mammals, the cetacean spinal cord lies within a highly vascularized space. We compared spinal cord size and vascular volumes within the vertebral canal across a sample of shallow and deep diving odontocetes. We predicted that the (a) spinal cord, a metabolically expensive tissue, would be relatively small, while (b) volumes of vascular structures would be relatively large, in deep versus shallow divers. Our sample included the shallow diving Tursiops truncatus (n = 2) and Delphinus delphis (n = 3), and deep diving Kogia breviceps (n = 2), Mesoplodon europaeus (n = 2), and Ziphius cavirostris (n = 1). Whole, frozen vertebral columns were cross-sectioned at each intervertebral disc, scaled photographs of vertebral canal contents acquired, and cross-sectional areas of structures digitally measured. Areas were multiplied by vertebral body lengths and summed to calculated volumes of neural and vascular structures. Allometric analyses revealed that the spinal cord scaled with negative allometry (b = 0.51 ± 0.13) with total body mass (TBM), and at a rate significantly lower than that of terrestrial mammals. As predicted, the spinal cord represented a smaller percentage of the total vertebral canal volume in the deep divers relative to shallow divers studied, as low as 2.8% in Z. cavirostris. Vascular volume scaled with positive allometry (b = 1.2 ± 0.22) with TBM and represented up to 96.1% (Z. cavirostris) of the total vertebral canal volume. The extreme deep diving beaked whales possessed 22-35 times more vascular volume than spinal cord volume within the vertebral canal, compared with the 6-10 ratio in the shallow diving delphinids. These data offer new insights into morphological specializations of neural and vascular structures that may contribute to differential diving capabilities across odontocete cetaceans.
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Affiliation(s)
- Carrie E Rowlands
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, North Carolina, USA
| | - William A McLellan
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, North Carolina, USA
| | - Sentiel A Rommel
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, North Carolina, USA
| | - Alexander M Costidis
- Virginia Aquarium Stranding Response Program, Virginia Aquarium and Marine Science Center, Virginia Beach, Virginia, USA
| | - Kara E Yopak
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, North Carolina, USA
| | - Heather N Koopman
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, North Carolina, USA
| | - Hillary L Glandon
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, North Carolina, USA
| | - D Ann Pabst
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, North Carolina, USA
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Arregui M, Singleton EM, Saavedra P, Pabst DA, Moore MJ, Sierra E, Rivero MA, Câmara N, Niemeyer M, Fahlman A, McLellan WA, Bernaldo de Quirós Y. Myoglobin Concentration and Oxygen Stores in Different Functional Muscle Groups from Three Small Cetacean Species. Animals (Basel) 2021; 11:ani11020451. [PMID: 33572177 PMCID: PMC7915992 DOI: 10.3390/ani11020451] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 01/30/2021] [Accepted: 02/02/2021] [Indexed: 01/18/2023] Open
Abstract
Simple Summary Marine mammals display several physiological adaptations to their marine environment. Higher myoglobin concentrations in their muscles compared to terrestrial mammals allow them to increase their onboard oxygen stores, enhancing the time available to dive. Most previous studies have calculated cetaceans’ onboard oxygen stores by assuming the myoglobin concentration of a single muscle to be representative of all the muscles in the body. In this study, we analyzed this assumption by comparing it to a more precise method that weighs all body muscles and measures myoglobin concentration in different functional groups. Abstract Compared with terrestrial mammals, marine mammals possess increased muscle myoglobin concentrations (Mb concentration, g Mb · 100g−1 muscle), enhancing their onboard oxygen (O2) stores and their aerobic dive limit. Although myoglobin is not homogeneously distributed, cetacean muscle O2 stores have been often determined by measuring Mb concentration from a single muscle sample (longissimus dorsi) and multiplying that value by the animal’s locomotor muscle or total muscle mass. This study serves to determine the accuracy of previous cetacean muscle O2 stores calculations. For that, body muscles from three delphinid species: Delphinus delphis, Stenella coeruleoalba, and Stenella frontalis, were dissected and weighed. Mb concentration was calculated from six muscles/muscle groups (epaxial, hypaxial and rectus abdominis; mastohumeralis; sternohyoideus; and dorsal scalenus), each representative of different functional groups (locomotion powering swimming, pectoral fin movement, feeding and respiration, respectively). Results demonstrated that the Mb concentration was heterogeneously distributed, being significantly higher in locomotor muscles. Locomotor muscles were the major contributors to total muscle O2 stores (mean 92.8%) due to their high Mb concentration and large muscle masses. Compared to this method, previous studies assuming homogenous Mb concentration distribution likely underestimated total muscle O2 stores by 10% when only considering locomotor muscles and overestimated them by 13% when total muscle mass was considered.
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Affiliation(s)
- Marina Arregui
- Atlantic Center for Cetacean Research, Institute of Animal Health and Food Safety (IUSA), Veterinary School, University of Las Palmas de Gran Canaria, C/Transmontaña s/n, 35413 Las Palmas, Spain; (M.A.); (M.A.R.); (N.C.); (Y.B.d.Q.)
| | - Emily M. Singleton
- Department of Biology and Marine Biology, University of North Carolina Wilmington, 601 S. College Road, Wilmington, NC 28403, USA; (E.M.S.); (D.A.P.); (W.A.M.)
| | - Pedro Saavedra
- Department of Mathematics, Campus de Tafira s/n, University of Las Palmas de Gran Canaria, 35017 Las Palmas, Spain;
| | - D. Ann Pabst
- Department of Biology and Marine Biology, University of North Carolina Wilmington, 601 S. College Road, Wilmington, NC 28403, USA; (E.M.S.); (D.A.P.); (W.A.M.)
| | - Michael J. Moore
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA;
| | - Eva Sierra
- Atlantic Center for Cetacean Research, Institute of Animal Health and Food Safety (IUSA), Veterinary School, University of Las Palmas de Gran Canaria, C/Transmontaña s/n, 35413 Las Palmas, Spain; (M.A.); (M.A.R.); (N.C.); (Y.B.d.Q.)
- Correspondence: ; Tel.: +34-928-4597-08
| | - Miguel A. Rivero
- Atlantic Center for Cetacean Research, Institute of Animal Health and Food Safety (IUSA), Veterinary School, University of Las Palmas de Gran Canaria, C/Transmontaña s/n, 35413 Las Palmas, Spain; (M.A.); (M.A.R.); (N.C.); (Y.B.d.Q.)
| | - Nakita Câmara
- Atlantic Center for Cetacean Research, Institute of Animal Health and Food Safety (IUSA), Veterinary School, University of Las Palmas de Gran Canaria, C/Transmontaña s/n, 35413 Las Palmas, Spain; (M.A.); (M.A.R.); (N.C.); (Y.B.d.Q.)
| | - Misty Niemeyer
- International Fund for Animal Welfare, Yarmouth Port, MA 02675, USA;
| | - Andreas Fahlman
- Global Diving Research Inc., Ottawa, ON K2J 5E8, Canada;
- Fundación Oceanogràphic, Department of Research, Ciutat de les Arts i de les Ciències, Carrer d’Eduardo Primo Yúfera, 1B, 46013 Valencia, Spain
- Department of Life Sciences, Texas A&M University-Corpus Christi, 6300 Ocean Drive, Unit 5892, Corpus Christi, TX 78412, USA
| | - William A. McLellan
- Department of Biology and Marine Biology, University of North Carolina Wilmington, 601 S. College Road, Wilmington, NC 28403, USA; (E.M.S.); (D.A.P.); (W.A.M.)
| | - Yara Bernaldo de Quirós
- Atlantic Center for Cetacean Research, Institute of Animal Health and Food Safety (IUSA), Veterinary School, University of Las Palmas de Gran Canaria, C/Transmontaña s/n, 35413 Las Palmas, Spain; (M.A.); (M.A.R.); (N.C.); (Y.B.d.Q.)
- Department of Life Sciences, Texas A&M University-Corpus Christi, 6300 Ocean Drive, Unit 5892, Corpus Christi, TX 78412, USA
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5
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Kroeger JP, McLellan WA, Arthur LH, Velten BP, Singleton EM, Kinsey ST, Pabst DA. Locomotor muscle morphology of three species of pelagic delphinids. J Morphol 2020; 281:170-182. [DOI: 10.1002/jmor.21089] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 07/31/2019] [Accepted: 09/09/2019] [Indexed: 12/20/2022]
Affiliation(s)
- Jacqueline P. Kroeger
- Department of Biology and Marine BiologyUniversity of North Carolina Wilmington Wilmington North Carolina
| | - William A. McLellan
- Department of Biology and Marine BiologyUniversity of North Carolina Wilmington Wilmington North Carolina
| | - Logan H. Arthur
- Department of Biology and Marine BiologyUniversity of North Carolina Wilmington Wilmington North Carolina
| | - Brandy P. Velten
- Department of Biology and Marine BiologyUniversity of North Carolina Wilmington Wilmington North Carolina
| | - Emily M. Singleton
- Department of Biology and Marine BiologyUniversity of North Carolina Wilmington Wilmington North Carolina
| | - Stephen T. Kinsey
- Department of Biology and Marine BiologyUniversity of North Carolina Wilmington Wilmington North Carolina
| | - D. Ann Pabst
- Department of Biology and Marine BiologyUniversity of North Carolina Wilmington Wilmington North Carolina
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ESTABLISHING MARGINAL LYMPH NODE ULTRASONOGRAPHIC CHARACTERISTICS IN HEALTHY BOTTLENOSE DOLPHINS ( TURSIOPS TRUNCATUS). J Zoo Wildl Med 2019; 48:961-971. [PMID: 29297828 DOI: 10.1638/2016-0251.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Pulmonary disease has been well documented in wild and managed dolphin populations. The marginal lymph nodes of the dolphin thorax provide lymphatic drainage to the lungs and can indicate pulmonary disease. This study standardized a technique for rapid, efficient, and thorough ultrasonographic evaluation of the marginal lymph nodes in bottlenose dolphins ( Tursiops truncatus). Thoracic ultrasonography was performed on 29 clinically healthy adult bottlenose dolphins. Reference intervals for lymph node dimensions and ultrasonographic characteristics of marginal lymph nodes were determined from four transducer orientations: longitudinal, transverse, oblique, and an orientation optimized to the ultrasonographer's eye. The relationship between lymph node dimensions and dolphin age, sex, length, weight, origin, and management setting (pool versus ocean enclosure) were also evaluated. The mean marginal lymph nodes measured 5.26 cm in length (SD = 1.10 cm, minimum = 3.04 cm, maximum = 7.61 cm, reference interval [10th to 90th percentiles per node dimension] 3.78-6.55 cm) and 3.72 cm in depth (SD = 0.59 cm, minimum = 2.64, maximum = 5.38 cm, reference interval 2.98-4.50 cm). Sex, dolphin length, weight, and management setting had no effect on lymph node dimensions. Dolphins >30 yr of age had longer node lengths than dolphins 5-10 yr old. Node dimensions did differ between dolphins from various origins. Most commonly, the lymph node was found to be hyperechoic relative to surrounding soft tissues (98%) and to have irregular caudal borders (84%), ill-defined deep borders (83%), flat superficial border (67%), triangular or rounded triangle shape (59%), irregular cranial border (55%), and moderate heterogeneity (34%). The data reported in this study serve as a baseline reference that may contribute to earlier detection of pleural and pulmonary disease of managed and wild cetacean populations.
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Fahlman A, Brodsky M, Miedler S, Dennison S, Ivančić M, Levine G, Rocho-Levine J, Manley M, Rocabert J, Borque-Espinosa A. Ventilation and gas exchange before and after voluntary static surface breath-holds in clinically healthy bottlenose dolphins, Tursiops truncatus. ACTA ACUST UNITED AC 2019; 222:jeb.192211. [PMID: 30760549 DOI: 10.1242/jeb.192211] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 02/05/2019] [Indexed: 01/14/2023]
Abstract
We measured respiratory flow (V̇), breathing frequency (f R), tidal volume (V T), breath duration and end-expired O2 content in bottlenose dolphins (Tursiops truncatus) before and after static surface breath-holds ranging from 34 to 292 s. There was considerable variation in the end-expired O2, V T and f R following a breath-hold. The analysis suggests that the dolphins attempt to minimize recovery following a dive by altering V T and f R to rapidly replenish the O2 stores. For the first breath following a surface breath-hold, the end-expired O2 decreased with dive duration, while V T and f R increased. Throughout the recovery period, end-expired O2 increased while the respiratory effort (V T, f R) decreased. We propose that the dolphins alter respiratory effort following a breath-hold according to the reduction in end-expired O2 levels, allowing almost complete recovery after 1.2 min.
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Affiliation(s)
- Andreas Fahlman
- Departamento de investigación, Fundación Oceanogràfic de la Comunitat Valenciana, Gran Vía Marqués del Turia 19, 46005 Valencia, Spain .,Departamento de Zoología, Grupo de Investigación Biomédica en Imagen GIBI230, Instituto de Investigación Sanitaria La Fe, Av. Fernando Abril Martorell 106, 46026 Valencia, Spain
| | - Micah Brodsky
- Micah Brodsky, V.M.D. Consulting, 1287 NE 96th Street, Miami Shores, FL 33138, USA
| | - Stefan Miedler
- Departamento de investigación, Fundación Oceanogràfic de la Comunitat Valenciana, Gran Vía Marqués del Turia 19, 46005 Valencia, Spain
| | - Sophie Dennison
- TeleVet Imaging Solutions, PLLC, PO BOX 3344, Oakton, VA 22124, USA
| | - Marina Ivančić
- Chicago Zoological Society, 3300 Golf Road, Brookfield, IL 60513, USA
| | - Gregg Levine
- Dolphin Quest, Oahu, 5000 Kahala Ave, Honolulu, HI 96816, USA
| | | | - Mercy Manley
- Siegfried & Roy's Secret Garden and Dolphin Habitat, The Mirage, Las Vegas, NV 89109, USA
| | - Joan Rocabert
- Mellow Design, C/ Bany dels pavesos 3, 46001 Valencia, Spain
| | - Alicia Borque-Espinosa
- Departamento de investigación, Fundación Oceanogràfic de la Comunitat Valenciana, Gran Vía Marqués del Turia 19, 46005 Valencia, Spain.,Departamento de Zoología, Grupo de Investigación Biomédica en Imagen GIBI230, Instituto de Investigación Sanitaria La Fe, Av. Fernando Abril Martorell 106, 46026 Valencia, Spain.,Universidad de Valencia, Av. de Blasco Ibáñez, 13, 46010 Valencia, Spain
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Fogarty MJ, Sieck GC. Evolution and Functional Differentiation of the Diaphragm Muscle of Mammals. Compr Physiol 2019; 9:715-766. [PMID: 30873594 PMCID: PMC7082849 DOI: 10.1002/cphy.c180012] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Symmorphosis is a concept of economy of biological design, whereby structural properties are matched to functional demands. According to symmorphosis, biological structures are never over designed to exceed functional demands. Based on this concept, the evolution of the diaphragm muscle (DIAm) in mammals is a tale of two structures, a membrane that separates and partitions the primitive coelomic cavity into separate abdominal and thoracic cavities and a muscle that serves as a pump to generate intra-abdominal (Pab ) and intrathoracic (Pth ) pressures. The DIAm partition evolved in reptiles from folds of the pleural and peritoneal membranes that was driven by the biological advantage of separating organs in the larger coelomic cavity into separate thoracic and abdominal cavities, especially with the evolution of aspiration breathing. The DIAm pump evolved from the advantage afforded by more effective generation of both a negative Pth for ventilation of the lungs and a positive Pab for venous return of blood to the heart and expulsive behaviors such as airway clearance, defecation, micturition, and child birth. © 2019 American Physiological Society. Compr Physiol 9:715-766, 2019.
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Affiliation(s)
- Matthew J Fogarty
- Mayo Clinic, Department of Physiology & Biomedical Engineering, Rochester, Minnesota, USA
| | - Gary C Sieck
- Mayo Clinic, Department of Physiology & Biomedical Engineering, Rochester, Minnesota, USA
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9
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Bonato M, Bagnoli P, Centelleghe C, Maric M, Brocca G, Mazzariol S, Cozzi B. Dynamics of blood circulation during diving in the bottlenose dolphin ( Tursiops truncatus): the role of the retia mirabilia. ACTA ACUST UNITED AC 2019; 222:jeb.198457. [PMID: 30760548 DOI: 10.1242/jeb.198457] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 02/01/2019] [Indexed: 11/20/2022]
Abstract
The retia mirabilia are vascular nets composed of small vessels dispersed among numerous veins, allowing blood storage, regulation of flow and pressure damping effects. Here, we investigated their potential role during the diving phase of the bottlenose dolphin (Tursiops truncatus). To this effect, the whole vertebral retia mirabilia of a series of dolphins were removed during post-mortem analysis and examined to assess vessel diameters, and estimate vascular volume and flow rate. We formulated a new hemodynamic model to help clarify vascular dynamics throughout the diving phase, based on the total blood volume of a bottlenose dolphin, and using data available about the perfusion of the main organs and body systems. We computed the minimum blood perfusion necessary to the internal organs, and the stroke volume and cardiac output during the surface state. We then simulated breath-holding conditions and perfusion of the internal organs under the diving-induced bradycardia and reduction of stroke volume and cardiac output, using 10 beats min-1 as the limit for the heart rate for an extended dive of over 3 min. Within these simulated conditions, the retia mirabilia play a vital role as reservoirs of oxygenated blood that permit functional performances and survival of the heart and brain. Our theoretical model, based on the actual blood capacity of the retia mirabilia and available data on organ perfusion, considers the dynamic trend of vasoconstriction during the diving phase and may represent a baseline for future studies on the diving physiology of dolphins and especially for the blood supply to their brain.
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Affiliation(s)
- Marco Bonato
- Department of Comparative Biomedicine and Food Science, University of Padova, 35020 Legnaro (PD), Italy.,Department of Biology, University of Padova, 35100 Padova (PD), Italy
| | - Paola Bagnoli
- Technology Transfer Office, Politecnico di Milano, 20133 Milan, Italy
| | - Cinzia Centelleghe
- Department of Comparative Biomedicine and Food Science, University of Padova, 35020 Legnaro (PD), Italy
| | - Mike Maric
- Department of Public Health, Experimental and Forensic Medicine, University of Pavia, 27100 Pavia (PV), Italy
| | - Ginevra Brocca
- Department of Comparative Biomedicine and Food Science, University of Padova, 35020 Legnaro (PD), Italy
| | - Sandro Mazzariol
- Department of Comparative Biomedicine and Food Science, University of Padova, 35020 Legnaro (PD), Italy
| | - Bruno Cozzi
- Department of Comparative Biomedicine and Food Science, University of Padova, 35020 Legnaro (PD), Italy
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10
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Fetherston T, Turner S, Mitchell G, Guzas E. Marine Mammal Lung Dynamics when Exposed to Underwater Explosion Impulse. Anat Rec (Hoboken) 2018; 302:718-734. [DOI: 10.1002/ar.24033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 02/22/2018] [Accepted: 04/16/2018] [Indexed: 11/10/2022]
Affiliation(s)
- Thomas Fetherston
- Naval Undersea Warfare Center 1176 Howell St., Newport Rhode Island 02841
| | - Stephen Turner
- Naval Undersea Warfare Center 1176 Howell St., Newport Rhode Island 02841
| | - Glenn Mitchell
- Naval Undersea Warfare Center 1176 Howell St., Newport Rhode Island 02841
| | - Emily Guzas
- Naval Undersea Warfare Center 1176 Howell St., Newport Rhode Island 02841
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11
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Ichikawa H, Matsuo T, Higurashi Y, Nagahisa H, Miyata H, Sugiura T, Wada N. Characteristics of Muscle Fiber-Type Distribution in Moles. Anat Rec (Hoboken) 2018; 302:1010-1023. [PMID: 30376699 DOI: 10.1002/ar.24008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 06/09/2018] [Accepted: 07/03/2018] [Indexed: 12/20/2022]
Abstract
Moles are a strictly fossorial Soricomorpha species and possess a suite of specialized adaptations to subterranean life. However, the contractile function of skeletal muscles in moles remains unclear. We compared muscle fiber-type distribution in two mole species (the large Japanese mole and lesser Japanese mole) with that in four other Soricomorpha species that are semi-fossorial, terrestrial, or semi-aquatic (the Japanese shrew-mole, house shrew, Japanese white-toothed shrew, and Japanese water shrew). For a single species, the fiber-type distribution in up to 38 muscles was assessed using immunohistochemical staining and/or gel electrophoresis. We found that slow and fatigue-resistant Type I fibers were absent in almost all muscles of all species studied. Although, the two methods of determining the fiber type did not give identical results, they both revealed that fast Type IIb fibers were absent in mole muscles. The fiber-type distribution was similar among different anatomical regions in the moles. This study demonstrated that the skeletal muscles of moles have a homogenous fiber-type distribution compared with that in Soricomorpha species that are not strictly fossorial. Mole muscles are composed of Type IIa fibers alone or a combination of Type IIa and relatively fast Type IIx fibers. The homogenous fiber-type distribution in mole muscles may be an adaptation to structurally simple subterranean environments, where there is no need to support body weight with the limbs, or to move at high speeds to pursue prey or to escape from predators. Anat Rec, 302:1010-1023, 2019. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Hiroshi Ichikawa
- Division of Basic Veterinary Sciences, the United Graduate School of Veterinary Science, Yamaguchi University, 1677-1 Yoshida, Yamaguchi, Yamaguchi, 753-8515, Japan
| | - Taiki Matsuo
- Division of Basic Veterinary Sciences, the United Graduate School of Veterinary Science, Yamaguchi University, 1677-1 Yoshida, Yamaguchi, Yamaguchi, 753-8515, Japan
| | - Yasuo Higurashi
- Laboratory of System Physiology, Division of Basic Veterinary Sciences, Joint Faculty of Veterinary Medicine, Yamaguchi University, 1677-1 Yoshida, Yamaguchi, Yamaguchi, 753-8515, Japan
| | - Hiroshi Nagahisa
- Department of Biological Sciences, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, 1677-1 Yoshida, Yamaguchi, Yamaguchi, 753-8515, Japan
| | - Hirofumi Miyata
- Department of Biological Sciences, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, 1677-1 Yoshida, Yamaguchi, Yamaguchi, 753-8515, Japan
| | - Takao Sugiura
- Department of Health and Sports Sciences, Faculty of Education, Yamaguchi University, 1677-1 Yoshida, Yamaguchi, Yamaguchi, 753-8513, Japan
| | - Naomi Wada
- Laboratory of System Physiology, Division of Basic Veterinary Sciences, Joint Faculty of Veterinary Medicine, Yamaguchi University, 1677-1 Yoshida, Yamaguchi, Yamaguchi, 753-8515, Japan
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12
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Lillie MA, Vogl AW, Raverty S, Haulena M, McLellan WA, Stenson GB, Shadwick RE. The caval sphincter in cetaceans and its predicted role in controlling venous flow during a dive. ACTA ACUST UNITED AC 2018; 221:jeb.177212. [PMID: 29674378 DOI: 10.1242/jeb.177212] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 04/10/2018] [Indexed: 11/20/2022]
Abstract
A sphincter on the inferior vena cava can protect the heart of a diving mammal from overload when elevated abdominal pressures increase venous return, yet sphincters are reported incompetent or absent in some cetacean species. We previously hypothesized that abdominal pressures are elevated and pulsatile in fluking cetaceans, and that collagen is deposited on the diaphragm according to pressure levels to resist deformation. Here, we tested the hypothesis that cetaceans generating high abdominal pressures need a more robust sphincter than those generating low pressures. We examined diaphragm morphology in seven cetacean and five pinniped species. All odontocetes had morphologically similar sphincters despite large differences in collagen content, and mysticetes had muscle that could modulate caval flow. These findings do not support the hypothesis that sphincter structure correlates with abdominal pressures. To understand why a sphincter is needed, we simulated the impact of oscillating abdominal pressures on caval flow. Under low abdominal pressures, simulated flow oscillated with each downstroke. Under elevated pressures, a vascular waterfall formed, greatly smoothing flow. We hypothesize that cetaceans maintain high abdominal pressures to moderate venous return and protect the heart while fluking, and use their sphincters only during low-fluking periods when abdominal pressures are low. We suggest that pinnipeds, which do not fluke, maintain low abdominal pressures. Simulations also showed that retrograde oscillations could be transmitted upstream from the cetacean abdomen and into the extradural veins, with potentially adverse repercussions for the cerebral circulation. We propose that locomotion-generated pressures have influenced multiple aspects of the cetacean vascular system.
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Affiliation(s)
- Margo A Lillie
- Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - A Wayne Vogl
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Stephen Raverty
- Animal Health Centre, 1767 Angus Campbell Road, Abbotsford, BC V3G 2M3, Canada
| | - Martin Haulena
- Vancouver Aquarium Marine Science Centre, PO Box 3232, Vancouver, BC V6G 3E2, Canada
| | - William A McLellan
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, NC 28403, USA
| | | | - Robert E Shadwick
- Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
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13
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Tanaka Y, Abella J, Aguirre-Fernández G, Gregori M, Fordyce RE. A new tropical Oligocene dolphin from Montañita/Olón, Santa Elena, Ecuador. PLoS One 2017; 12:e0188380. [PMID: 29261688 PMCID: PMC5737981 DOI: 10.1371/journal.pone.0188380] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 10/31/2017] [Indexed: 11/18/2022] Open
Abstract
A new small probable Oligocene dolphin from Ecuador represents a new genus and species, Urkudelphis chawpipacha. The new taxon is known from a single juvenile skull and earbones; it differs from other archaic dolphins in features including widely exposed frontals at the vertex, a dorsally wide open vomer at the mesorostral groove, and a strongly projected and pointed lateral tuberosity of the periotic. Phylogenetic analysis places it toward the base of the largely-extinct clade Platanistoidea. The fossil is one of a few records of tropical fossil dolphins.
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Affiliation(s)
- Yoshihiro Tanaka
- Osaka Museum of Natural History, Osaka, Japan
- Numata Fossil Museum, Hokkaido, Japan
- Division of Academic Resources and Specimens, Hokkaido University Museum, Sapporo, Hokkaido, Japan
| | - Juan Abella
- Facultad de Ciencias del Mar, Universidad Estatal Península de Santa Elena, Santa Elena, Ecuador
- Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona, Edifici ICP, Campus de la UAB, Cerdanyola del Vallès, Barcelona, Spain
| | | | - Maria Gregori
- Facultad de Ciencias del Mar, Universidad Estatal Península de Santa Elena, Santa Elena, Ecuador
| | - R. Ewan Fordyce
- Department of Geology, University of Otago, Dunedin, New Zealand
- Departments of Paleobiology and Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, United States of America
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14
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Lillie MA, Vogl AW, Raverty S, Haulena M, McLellan WA, Stenson GB, Shadwick RE. Controlling thoracic pressures in cetaceans during a breath-hold dive: importance of the diaphragm. J Exp Biol 2017; 220:3464-3477. [DOI: 10.1242/jeb.162289] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 07/17/2017] [Indexed: 11/20/2022]
Abstract
ABSTRACT
Internal pressures change throughout a cetacean's body during swimming or diving, and uneven pressures between the thoracic and abdominal compartments can affect the cardiovascular system. Pressure differentials could arise from ventral compression on each fluke downstroke or by a faster equilibration of the abdominal compartment with changing ambient ocean pressures compared with the thoracic compartment. If significant pressure differentials do develop, we would expect the morphology of the diaphragm to adapt to its in vivo loading. Here, we tested the hypothesis that significant pressure differentials develop between the thoracic and abdominal cavities in diving cetaceans by examining diaphragms from several cetacean and pinniped species. We found that: (1) regions of cetacean diaphragms possess subserosal collagen fibres that would stabilize the diaphragm against craniocaudal stretch; (2) subserosal collagen covers 5–60% of the thoracic diaphragm surface, and area correlates strongly with published values for swimming speed of each cetacean species (P<0.001); and (3) pinnipeds, which do not locomote by vertical fluking, do not possess this subserosal collagen. These results strongly suggest that this collagen is associated with loads experienced during a dive, and they support the hypothesis that diving cetaceans experience periods during which abdominal pressures significantly exceed thoracic pressures. Our results are consistent with the generation of pressure differentials by fluking and by different compartmental equilibration rates. Pressure differentials during diving would affect venous and arterial perfusion and alter transmural pressures in abdominal arteries.
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Affiliation(s)
- Margo A. Lillie
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
| | - A. Wayne Vogl
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada V6T 1Z3
| | - Stephen Raverty
- Animal Health Centre, 1767 Angus Campbell Road, Abbotsford, BC, Canada V3G 2M3
| | - Martin Haulena
- Vancouver Aquarium Marine Science Centre, PO Box 3232, Vancouver, BC, Canada V6G 3E2
| | - William A. McLellan
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, NC 28403, USA
| | | | - Robert E. Shadwick
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
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15
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Thometz NM, Dearolf JL, Dunkin RC, Noren DP, Holt MM, Sims OC, Cathey BC, Williams TM. Comparative physiology of vocal musculature in two odontocetes, the bottlenose dolphin (Tursiops truncatus) and the harbor porpoise (Phocoena phocoena). J Comp Physiol B 2017; 188:177-193. [PMID: 28569355 DOI: 10.1007/s00360-017-1106-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 05/11/2017] [Indexed: 10/19/2022]
Abstract
The mechanism by which odontocetes produce sound is unique among mammals. To gain insight into the physiological properties that support sound production in toothed whales, we examined myoglobin content ([Mb]), non-bicarbonate buffering capacity (β), fiber-type profiles, and myosin heavy chain expression of vocal musculature in two odontocetes: the bottlenose dolphin (Tursiops truncatus; n = 4) and the harbor porpoise (Phocoena phocoena; n = 5). Both species use the same anatomical structures to produce sound, but differ markedly in their vocal repertoires. Tursiops produce both broadband clicks and tonal whistles, while Phocoena only produce higher frequency clicks. Specific muscles examined in this study included: (1) the nasal musculature around the phonic lips on the right (RNM) and left (LNM) sides of the head, (2) the palatopharyngeal sphincter (PPS), which surrounds the larynx and aids in pressurizing cranial air spaces, and (3) the genioglossus complex (GGC), a group of muscles positioned ventrally within the head. Overall, vocal muscles had significantly lower [Mb] and β than locomotor muscles from the same species. The PPS was predominately composed of small diameter slow-twitch fibers. Fiber-type and myosin heavy chain analyses revealed that the GGC was comprised largely of fast-twitch fibers (Tursiops: 88.6%, Phocoena: 79.7%) and had the highest β of all vocal muscles. Notably, there was a significant difference in [Mb] between the RNM and LNM in Tursiops, but not Phocoena. Our results reveal shared physiological characteristics of individual vocal muscles across species that enhance our understanding of key functional roles, as well as species-specific differences which appear to reflect differences in vocal capacities.
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Affiliation(s)
- Nicole M Thometz
- Department of Biology, University of San Francisco, 2130 Fulton St, San Francisco, CA, 94117, USA. .,Department of Ecology and Evolutionary Biology, Long Marine Laboratory, University of California at Santa Cruz, 115 McAllister Way, Santa Cruz, CA, 95060, USA.
| | - Jennifer L Dearolf
- Biology Department, Hendrix College, 1600 Washington Ave., Conway, AR, 72032, USA
| | - Robin C Dunkin
- Department of Ecology and Evolutionary Biology, Long Marine Laboratory, University of California at Santa Cruz, 115 McAllister Way, Santa Cruz, CA, 95060, USA
| | - Dawn P Noren
- Conservation Biology Division, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 2725 Montlake Boulevard East, Seattle, WA, 98112, USA
| | - Marla M Holt
- Conservation Biology Division, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 2725 Montlake Boulevard East, Seattle, WA, 98112, USA
| | - Olivia C Sims
- Biology Department, Hendrix College, 1600 Washington Ave., Conway, AR, 72032, USA
| | - Brandon C Cathey
- Biology Department, Hendrix College, 1600 Washington Ave., Conway, AR, 72032, USA
| | - Terrie M Williams
- Department of Ecology and Evolutionary Biology, Long Marine Laboratory, University of California at Santa Cruz, 115 McAllister Way, Santa Cruz, CA, 95060, USA
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16
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Fahlman A, Moore MJ, Garcia-Parraga D. Respiratory function and mechanics in pinnipeds and cetaceans. J Exp Biol 2017; 220:1761-1773. [DOI: 10.1242/jeb.126870] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
ABSTRACT
In this Review, we focus on the functional properties of the respiratory system of pinnipeds and cetaceans, and briefly summarize the underlying anatomy; in doing so, we provide an overview of what is currently known about their respiratory physiology and mechanics. While exposure to high pressure is a common challenge among breath-hold divers, there is a large variation in respiratory anatomy, function and capacity between species – how are these traits adapted to allow the animals to withstand the physiological challenges faced during dives? The ultra-deep diving feats of some marine mammals defy our current understanding of respiratory physiology and lung mechanics. These animals cope daily with lung compression, alveolar collapse, transient hyperoxia and extreme hypoxia. By improving our understanding of respiratory physiology under these conditions, we will be better able to define the physiological constraints imposed on these animals, and how these limitations may affect the survival of marine mammals in a changing environment. Many of the respiratory traits to survive exposure to an extreme environment may inspire novel treatments for a variety of respiratory problems in humans.
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Affiliation(s)
- Andreas Fahlman
- Fundación Oceanográfic de la Comunidad Valenciana, Gran Vía Marques del Turia 19, Valencia 46005, Spain
- Department of Life Sciences, Texas A&M University-Corpus Christi, 6300 Ocean Drive, Corpus Christi, TX 78412, USA
| | - Michael J. Moore
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Daniel Garcia-Parraga
- Fundación Oceanográfic de la Comunidad Valenciana, Gran Vía Marques del Turia 19, Valencia 46005, Spain
- Oceanográfic-Avanqua, Ciudad de las Artes y las Ciencias, Valencia 46013, Spain
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17
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Fahlman A, Loring SH, Levine G, Rocho-Levine J, Austin T, Brodsky M. Lung mechanics and pulmonary function testing in cetaceans. J Exp Biol 2015; 218:2030-8. [DOI: 10.1242/jeb.119149] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
ABSTRACT
We measured esophageal pressures, respiratory flow rates, and expired O2 and CO2 in six adult bottlenose dolphins (Tursiops truncatus) during voluntary breaths and maximal (chuff) respiratory efforts. The data were used to estimate the dynamic specific lung compliance (sCL), the O2 consumption rate (V̇O2) and CO2 production rates (V̇CO2) during rest. Our results indicate that bottlenose dolphins have the capacity to generate respiratory flow rates that exceed 130 l s−1 and 30 l s−1 during expiration and inspiration, respectively. The esophageal pressures indicated that expiration is passive during voluntary breaths, but active during maximal efforts, whereas inspiration is active for all breaths. The average sCL of dolphins was 0.31±0.04 cmH2O−1, which is considerably higher than that of humans (0.08 cmH2O−1) and that previously measured in a pilot whale (0.13 cmH2O−1). The average estimated V̇O2 and V̇CO2 using our breath-by-breath respirometry system ranged from 0.857 to 1.185 l O2 min−1 and 0.589 to 0.851 l CO2 min−1, respectively, which is similar to previously published metabolic measurements from the same animals using conventional flow-through respirometry. In addition, our custom-made system allows us to approximate end tidal gas composition. Our measurements provide novel data for respiratory physiology in cetaceans, which may be important for clinical medicine and conservation efforts.
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Affiliation(s)
- Andreas Fahlman
- Department of Life Science, Texas A&M University-Corpus Christi, 6300 Ocean Drive, Corpus Christi, TX 78412, USA
| | - Stephen H. Loring
- Department of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
| | - Gregg Levine
- Dolphin Quest, Oahu, 5000 Kahala Ave, Honolulu, HI 96816, USA
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18
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Moore CD, Crocker DE, Fahlman A, Moore MJ, Willoughby DS, Robbins KA, Kanatous SB, Trumble SJ. Ontogenetic changes in skeletal muscle fiber type, fiber diameter and myoglobin concentration in the Northern elephant seal (Mirounga angustirostris). Front Physiol 2014; 5:217. [PMID: 24959151 PMCID: PMC4050301 DOI: 10.3389/fphys.2014.00217] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2014] [Accepted: 05/20/2014] [Indexed: 11/13/2022] Open
Abstract
Northern elephant seals (Mirounga angustirostris) (NES) are known to be deep, long-duration divers and to sustain long-repeated patterns of breath-hold, or apnea. Some phocid dives remain within the bounds of aerobic metabolism, accompanied by physiological responses inducing lung compression, bradycardia, and peripheral vasoconstriction. Current data suggest an absence of type IIb fibers in pinniped locomotory musculature. To date, no fiber type data exist for NES, a consummate deep diver. In this study, NES were biopsied in the wild. Ontogenetic changes in skeletal muscle were revealed through succinate dehydrogenase (SDH) based fiber typing. Results indicated a predominance of uniformly shaped, large type I fibers and elevated myoglobin (Mb) concentrations in the longissimus dorsi (LD) muscle of adults. No type II muscle fibers were detected in any adult sampled. This was in contrast to the juvenile animals that demonstrated type II myosin in Western Blot analysis, indicative of an ontogenetic change in skeletal muscle with maturation. These data support previous hypotheses that the absence of type II fibers indicates reliance on aerobic metabolism during dives, as well as a depressed metabolic rate and low energy locomotion. We also suggest that the lack of type IIb fibers (adults) may provide a protection against ischemia reperfusion (IR) injury in vasoconstricted peripheral skeletal muscle.
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Affiliation(s)
- Colby D Moore
- Department of Biology, Baylor University Waco, TX, USA
| | - Daniel E Crocker
- Department of Biology, Sonoma State University Rohnert Park, CA, USA
| | - Andreas Fahlman
- Department of Life Sciences, Texas A&M University Corpus Christi, TX, USA
| | - Michael J Moore
- Department of Biology, Woods Hole Oceanographic Institution Woods Hole, MA, USA
| | - Darryn S Willoughby
- Department of Health, Human Performance and Recreation, Baylor University Waco, TX, USA
| | | | - Shane B Kanatous
- Department of Biology, College of Natural Sciences, Colorado State University Fort Collins, CO, USA
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19
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Ivančić M, Solano M, Smith CR. Computed tomography and cross-sectional anatomy of the thorax of the live bottlenose dolphin (Tursiops truncatus). Anat Rec (Hoboken) 2014; 297:901-15. [PMID: 24596254 DOI: 10.1002/ar.22900] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2013] [Accepted: 01/07/2014] [Indexed: 12/20/2022]
Abstract
Pulmonary disease is one of the leading causes of cetacean morbidity and mortality in the wild and in managed collections. The purpose of this study was to present the computed tomographic (CT) appearance of the thorax of the live bottlenose dolphin (Tursiops truncatus) out-of-water and to describe the technical and logistical parameters involved in CT image acquisition in this species. Six thoracic CT evaluations of four conscious adult bottlenose dolphins were performed between April 2007 and May 2012. Animals were trained to slide out of the water onto foam pads and were transported in covered trucks to a human CT facility. Under light sedation, animals were secured in sternal recumbency for acquisition of CT data. Non-contrast helical images were obtained during an end-inspiratory breath hold. Diagnostic, high quality images were obtained in all cases. Respiratory motion was largely insignificant due to the species' apneustic respiratory pattern. CT findings characteristic of this species include the presence of a bronchus trachealis, absence of lung lobation, cranial cervical extension of the lung, lack of conspicuity of intrathoracic lymph nodes, and presence of retia mirabilia. Dorsoventral narrowing of the heart relative to the thorax was seen in all animals and is suspected to be an artifact of gravity loading. Diagnostic thoracic computed tomography of live cetaceans is feasible and likely to prove clinically valuable. A detailed series of cross-sectional reference images is provided.
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Affiliation(s)
- Marina Ivančić
- National Marine Mammal Foundation, San Diego, California
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20
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Piscitelli MA, Raverty SA, Lillie MA, Shadwick RE. A review of cetacean lung morphology and mechanics. J Morphol 2013; 274:1425-40. [DOI: 10.1002/jmor.20192] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Revised: 06/25/2013] [Accepted: 08/05/2013] [Indexed: 12/20/2022]
Affiliation(s)
- Marina A. Piscitelli
- Department of Zoology; University of British Columbia; Vancouver British Columbia Canada V6T 1Z4
| | - Stephen A. Raverty
- Department of Zoology; University of British Columbia; Vancouver British Columbia Canada V6T 1Z4
- Division of Plant and Animal Health; British Columbia Ministry of Agriculture; Abbotsford British Columbia Canada V3G 2M3
| | - Margo A. Lillie
- Department of Zoology; University of British Columbia; Vancouver British Columbia Canada V6T 1Z4
| | - Robert E. Shadwick
- Department of Zoology; University of British Columbia; Vancouver British Columbia Canada V6T 1Z4
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21
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Lillie MA, Piscitelli MA, Vogl AW, Gosline JM, Shadwick RE. Cardiovascular design in fin whales: high-stiffness arteries protect against adverse pressure gradients at depth. J Exp Biol 2013; 216:2548-63. [DOI: 10.1242/jeb.081802] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
SUMMARY
Fin whales have an incompliant aorta, which, we hypothesize, represents an adaptation to large, depth-induced variations in arterial transmural pressures. We hypothesize these variations arise from a limited ability of tissues to respond to rapid changes in ambient ocean pressures during a dive. We tested this hypothesis by measuring arterial mechanics experimentally and modelling arterial transmural pressures mathematically. The mechanical properties of mammalian arteries reflect the physiological loads they experience, so we examined a wide range of fin whale arteries. All arteries had abundant adventitial collagen that was usually recruited at very low stretches and inflation pressures (2–3 kPa), making arterial diameter largely independent of transmural pressure. Arteries withstood significant negative transmural pressures (−7 to −50 kPa) before collapsing. Collapse was resisted by recruitment of adventitial collagen at very low stretches. These findings are compatible with the hypothesis of depth-induced variation of arterial transmural pressure. Because transmural pressures depend on thoracic pressures, we modelled the thorax of a diving fin whale to assess the likelihood of significant variation in transmural pressures. The model predicted that deformation of the thorax body wall and diaphragm could not always equalize thoracic and ambient pressures because of asymmetrical conditions on dive descent and ascent. Redistribution of blood could partially compensate for asymmetrical conditions, but inertial and viscoelastic lag necessarily limits tissue response rates. Without pressure equilibrium, particularly when ambient pressures change rapidly, internal pressure gradients will develop and expose arteries to transient pressure fluctuations, but with minimal hemodynamic consequence due to their low compliance.
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Affiliation(s)
- M. A. Lillie
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
| | - M. A. Piscitelli
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
| | - A. W. Vogl
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
| | - J. M. Gosline
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
| | - R. E. Shadwick
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
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22
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Hirasawa T, Kuratani S. A new scenario of the evolutionary derivation of the mammalian diaphragm from shoulder muscles. J Anat 2013; 222:504-17. [PMID: 23448284 PMCID: PMC3633340 DOI: 10.1111/joa.12037] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/14/2013] [Indexed: 12/30/2022] Open
Abstract
The evolutionary origin of the diaphragm remains unclear, due to the lack of a comparable structure in other extant taxa. However, recent researches into the developmental mechanism of this structure have yielded new insights into its origin. Here we summarize current understanding regarding the development of the diaphragm, and present a possible scenario for the evolutionary acquisition of this uniquely mammalian structure. Recent developmental analyses indicate that the diaphragm and forelimb muscles are derived from a shared cell population during embryonic development. Therefore, the embryonic positions of forelimb muscle progenitors, which correspond to the position of the brachial plexus, likely played an important role in the evolution of the diaphragm. We surveyed the literature to reexamine the position of the brachial plexus among living amniotes and confirmed that the cervico-thoracic transition in ribs reflects the brachial plexus position. Using this osteological correlate, we concluded that the anterior borders of the brachial plexuses in the stem synapsids were positioned at the level of the fourth spinal nerve, suggesting that the forelimb buds were laid in close proximity of the infrahyoid muscles. The topology of the phrenic and suprascapular nerves of mammals is similar to that of subscapular and supracoracoid nerves, respectively, of the other amniotes, suggesting that the diaphragm evolved from a muscle positioned medial to the pectoral girdle (cf. subscapular muscle). We hypothesize that the diaphragm was acquired in two steps: first, forelimb muscle cells were incorporated into tissues to form a primitive diaphragm in the stem synapsid grade, and second, the diaphragm in cynodonts became entrapped in the region controlled by pulmonary development.
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Affiliation(s)
- Tatsuya Hirasawa
- Laboratory for Evolutionary Morphology, RIKEN Center for Developmental Biology, Kobe, Japan.
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23
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Kielhorn CE, Dillaman RM, Kinsey ST, McLellan WA, Mark Gay D, Dearolf JL, Ann Pabst D. Locomotor muscle profile of a deep (Kogia breviceps) versus shallow (Tursiops truncatus) diving cetacean. J Morphol 2013; 274:663-75. [DOI: 10.1002/jmor.20124] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 10/31/2012] [Accepted: 12/16/2012] [Indexed: 01/08/2023]
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Velten BP, Dillaman RM, Kinsey ST, McLellan WA, Pabst DA. Novel locomotor muscle design in extreme deep-diving whales. J Exp Biol 2013; 216:1862-71. [DOI: 10.1242/jeb.081323] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Summary
Most marine mammals are hypothesized to routinely dive within their aerobic dive limit (ADL). Mammals that regularly perform deep, long-duration dives have locomotor muscles with elevated myoglobin concentrations and are composed of predominantly large, slow-twitch (Type I) fibers with low mitochondrial volume densities (Vmt). These features contribute to extending ADL by increasing oxygen stores and decreasing metabolic rate. Recent tagging studies, however, have challenged the view that two groups of extreme deep-diving cetaceans dive within their ADLs. Beaked whales (Ziphius cavirostris, Cuvier and Mesoplodon densirostris, Blainville) routinely perform the deepest and longest average dives of any air-breathing vertebrate, and short-finned pilot whales (Globicephala macrorhynchus, Gray) perform high-speed sprints at depth. We investigated the locomotor muscle morphology and estimated total body oxygen stores of these cetaceans to determine whether they (a) shared muscle design features with other deep-divers and (b) performed dives within their calculated ADLs. Muscle of both cetaceans displayed high myoglobin concentrations and large fibers, as predicted, but novel fiber profiles for diving mammals. Beaked whales possessed a sprinter's fiber-type profile, composed of approximately 80% fast-twitch (Type II) fibers with low Vmt. Approximately one-third of the muscle fibers of short-finned pilot whales were slow-twitch, oxidative, glycolytic fibers, a rare fiber-type for any mammal. The muscle morphology of beaked whales likely decreases the energetic cost of diving, while that of short-finned pilot whales supports high activity events. Calculated ADLs indicate that, at low metabolic rates, both cetaceans carry sufficient onboard oxygen to aerobically support their dives.
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Moore C, Moore M, Trumble S, Niemeyer M, Lentell B, McLellan W, Costidis A, Fahlman A. A comparative analysis of marine mammal tracheas. J Exp Biol 2013; 217:1154-66. [DOI: 10.1242/jeb.093146] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Summary
In 1940, Scholander suggested that stiffened upper airways remained open and received air from highly compressible alveoli during marine mammal diving. There are little data available on the structural and functional adaptations of the marine mammal respiratory system. The aim of this research was to investigate the anatomical (gross) and structural (compliance) characteristics of excised marine mammal tracheas. Here we defined different types of tracheal structures, categorizing pinniped tracheas by varying degrees of continuity of cartilage (categories 1-4) and cetacean tracheas by varying compliance values (categories 5A and 5B). Some tracheas fell into more than one category, along their length, for example, the harbor seal (Phoca vitulina) demonstrated complete rings cranially, and as the trachea progressed caudally tracheal rings changed morphology. Dolphins and porpoises had less stiff, more compliant spiraling rings while beaked whales had very stiff, less compliant spiraling rings. The pressure-volume (P-V) relationships of isolated tracheas from different species were measured to assess structural differences between species. These findings lend evidence for pressure-induced collapse and re-inflation of lungs, perhaps influencing variability in dive depth or ventilation rates of the species investigated.
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Piscitelli MA, McLellan WA, Rommel SA, Blum JE, Barco SG, Pabst DA. Lung size and thoracic morphology in shallow- and deep-diving cetaceans. J Morphol 2010; 271:654-73. [DOI: 10.1002/jmor.10823] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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