Hey guys, This came up in my recent preparation for an upcoming physiology exam.
ID: 3519916 • 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
1) Giraffes the tallest extant animals and are renowed for their high central arterial blood pressure, which is necessary to secure brain perfusion, the giraffes have a heart with a small intraventricular cavity and a relativley thick ventricular wall allowing for generation of high aterial pressures at noemal left ventricular wall tension, this adaptations results in left ventricular wall tensions but produce a lowered cardiac output. 2)Giraffe skin is thick and tight helps in maintainning the blood pressure, dermal armour or thermoregulation , the tight skin surrounding the extremities of the giraffe aids in the movement of fluid against gravity hence preventing the pooling of blood and tissue fluid(edema) but the skin has also been implicated in the thermoregulatory capacities and denfensive anatomy. 3)The giraffes are adapted to the high blood pressure and do not suffer any consequences as seen in humans, the giraffe heart has evolved to have thicker muscle walls and a small radius giving it great power, and also the walls of the blood pressure also thickens with age as the giraffes neck grows longer, to avoid rupturing under increasing pressure, and the blood pressure also depends upon the the way of adjusting the capacity of the cardiovascular system and are able to shrink and expand their blood vessels to change the volume of the cardiovascular system very efficiently.