Premium
The structure of giraffe resistance arteries from muscular beds correlates with the height above ground
Author(s) -
Aalkjaer Christian,
Broegger Torbjoern,
Tilenius Niklas,
Broendum Emil Toft
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.1071.14
Subject(s) - myograph , anatomy , medicine , artery , cardiology
The arterial pressure varies substantially within a giraffe. Giraffes, thus, provide ideal animals to test whether the structure of the resistance arteries reflects the transmural pressure. We dissected out small arteries from biopsies of leg muscles (ca. 80 cm above ground) and muscles from lower and upper neck (40 cm and 150 cm above the heart, neck1 and neck2, respectively from six male giraffes ( Giraffa camleopardalis). The transmural pressures in the conduits at the three levels are ca. 300, 170 and 100 mmHg, respectively. The arteries were mounted in a myograph and normalized based on the passive length‐tension relationship. The normalized diameters of the arteries were 171±17 μm, 192±6 μm, 187±24 μm leg, neck1 and neck2, respectively, and did not differ, whereas the media thickness and force production (expressed as equivalent pressure) decreased significantly with the height above ground and were media thickness: 25±2 μm, 16±1 μm and 12±0 μm, leg, neck1 and neck2, respectively and equivalent pressure: 66±6 kPa, 52±6 kPa and 41±6 kPa, leg, neck1 and neck2, respectively. We conclude that resistance artery structure and consequently their function follows the transmural pressure.