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Animal Blood pressure
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Which animal is considered to have the highest blood pressure
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Tests have shown that the blood pressure at the base of the giraffe's brain is 200 mm HG (millimeters of Mercury) when the giraffe is upright and, during tests, instead of being higher as expected, dropped to 175 mm Hg when the head was lowered.
As in most ruminants, the blood reaches the brain from the heart by way of the common and external carotid arteries. The two external carotids divide,just before each reaches the brain, into many small vessels forming a tight network that is called the rete mirabile. The vessels of the giraffe rete have elastic walls which can accommodate excess blood when the head is lowered so that the brain is not flooded. As a further safeguard for the brain while the giraffe is in this position, a connection between the carotid artery and the vertebral artery drains off a portion of the blood even before it reaches this network. The walls of the rete mirabile vessels are also elastic enough to retain sufficient blood when the head is raised so that the brain's supply is not depleted momentarily during the system's pressure changes.
Interestingly, with few exceptions the course of the blood vessels of the skin corresponds with the white background lines on the coat of the giraffe. One would surmise that this configuration would aid in dumping heat. Blood in vessels under the dark patches would tend to be warmed.
(Source: The Giraffe, Its Biology, Behavior, and Ecology)
As in most ruminants, the blood reaches the brain from the heart by way of the common and external carotid arteries. The two external carotids divide,just before each reaches the brain, into many small vessels forming a tight network that is called the rete mirabile. The vessels of the giraffe rete have elastic walls which can accommodate excess blood when the head is lowered so that the brain is not flooded. As a further safeguard for the brain while the giraffe is in this position, a connection between the carotid artery and the vertebral artery drains off a portion of the blood even before it reaches this network. The walls of the rete mirabile vessels are also elastic enough to retain sufficient blood when the head is raised so that the brain's supply is not depleted momentarily during the system's pressure changes.
Interestingly, with few exceptions the course of the blood vessels of the skin corresponds with the white background lines on the coat of the giraffe. One would surmise that this configuration would aid in dumping heat. Blood in vessels under the dark patches would tend to be warmed.
(Source: The Giraffe, Its Biology, Behavior, and Ecology)
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