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More specifically, the sensitivity of carotid body chemoreceptors to decreased PO 2 is greater when pH is decreased and PCO 2 is increased. Impulse rate for carotid bodies is particularly sensitive to changes in arterial PO2 in the range of 60 down to 30 mm Hg, a range in which hemoglobin saturation with oxygen decreases rapidly. [5]
In utero and at birth, the carotid body's response to hypoxia is not fully developed; it takes a few days to a few weeks to increase its sensitivity to that of an adult carotid body. During this period of development, it is proposed that neonates heavily rely on other oxygen-sensing chemoreceptors, such as the aortic body or central ...
It is a condition known as 'carotid sinus hypersensitivity' (CSH), 'carotid sinus syndrome' or 'carotid sinus syncope', in which manual stimulation causes large changes in heart rate and blood pressure, which can result in bradycardia, vasodilation, and hypotension.
In the carotid body the respiratory chemoreceptors need a period of time postnatally in order to reach functional maturity. [10] This maturation period is known as resetting. [11] At birth the chemorecptors express a low sensitivity for lack of oxygen but this increases over the first few days or weeks of life.
These are sensitive to pH and CO 2. [19] peripheral chemoreceptors: consists of aortic and carotid bodies. Aortic body detects changes in blood oxygen and carbon dioxide, but not pH, while carotid body detects all three. They do not desensitize. Their effect on breathing rate is less than that of the central chemoreceptors.
Peripheral chemoreceptors (carotid and aortic bodies) and central chemoreceptors (medullary neurons) primarily function to regulate respiratory activity. This is an important mechanism for maintaining arterial blood pO2, pCO2 , and pH within appropriate physiological ranges.
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The baroreflex or baroreceptor reflex is one of the body's homeostatic mechanisms that helps to maintain blood pressure at nearly constant levels. The baroreflex provides a rapid negative feedback loop in which an elevated blood pressure causes the heart rate to decrease. Decreased blood pressure decreases baroreflex activation and causes heart ...