Aalkjær Christian, Wang Tobias
Department of Biomedicine, Aarhus University, 8000, Aarhus C, Denmark.
Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark.
J Muscle Res Cell Motil. 2023 Jun;44(2):53-60. doi: 10.1007/s10974-022-09626-0. Epub 2022 Jul 25.
Giraffes are the highest living animals on Earth and therefore are challenged by gravity more than any other species. In particular the cardiovascular system needs to adapt to this challenge. Giraffes have a mean blood pressure around 200 mmHg, which ensures a mean arterial pressure near the head of 100 mmHg when the giraffe is standing with the neck in a near vertical position. This immediately raises several questions. How do giraffes avoid edema in the legs where the arterial pressure is 300 mmHg or higher? How does the heart produce a pressure of 200 mmHg, and what is the energy required for this endeavor? How can the kidney tolerate a pressure of about 200 mmHg and does this mean that giraffes have a high glomerular filtration rate? What is the arterial pressure in the head of giraffes when they drink, and how is perfusion of the brain maintained when they lift their head after drinking? In this short review, we present some answers to these questions.
长颈鹿是地球上现存最高的动物，因此比其他任何物种都更容易受到重力的挑战。特别是心血管系统需要适应这一挑战。长颈鹿的平均血压约为200毫米汞柱，当长颈鹿颈部接近垂直站立时，这能确保头部附近的平均动脉压为100毫米汞柱。这立即引发了几个问题。长颈鹿如何避免腿部动脉压为300毫米汞柱或更高时出现水肿？心脏如何产生200毫米汞柱的压力，以及为此需要多少能量？肾脏如何耐受约200毫米汞柱的压力，这是否意味着长颈鹿有较高的肾小球滤过率？长颈鹿饮水时头部的动脉压是多少，饮水后抬起头时大脑的灌注是如何维持的？在这篇简短的综述中，我们给出了这些问题的一些答案。
