Hey guys, This came up in my recent preparation for an upcoming physiology exam.
ID: 3519927 • Letter: H
Question
Hey guys, This came up in my recent preparation for an upcoming physiology exam. Can someone please explain in full. Thank you in advance! Q20. The fact that giraffes have the ability to lower their heads and raise them without a discernable effect on their mean arterial pressure (MAP) has baffled veterinarians and researchers for many years. However, important clues are being revealed. One approach to understanding this phenomenon, for example, has been to make anatomical observations of the giraffe’s heart. Such studies have revealed that the left ventricular wall of a giraffe is much thicker relative to its body mass compared with other species (including humans).
i) How may a thicker left ventricular wall contribute to the higher arterial pressure observed in a giraffe? Include your physiological reasoning [2 marks].
ii) Another observation is that the skin of the giraffe is extremely thick and tight, particularly in their lower extremities. How may this skin property influence the arterial pressures observed in a giraffe? [3 marks].
iii) List ONE other possible mechanism that could contribute to high resting blood pressure in a giraffe (or a human)? Briefly explain this mechanism [2 marks].
Explanation / Answer
(i( In case of Giraffes higher atrial pressure which may exceed up to 300mmHg.In giraffe intraventicular cavity of heart is small however ventricular wall is thick which lead to the high atrial pressure at left ventricular tension. Here cardiac output is determined by inert gas rebreathing which provide additional stroke volume.
(ii) Thickness of the skin play an important role in the maintanance of the blood pressure in giraffe. Tight skin may lead to movement of the fluid against the gravity. Moreover skin of the neck and legs may help in the cardiovascular regulation of the blood flow from head and leg.