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Their function is to sense pressure changes by responding to change in the tension of the arterial wall. [1] The baroreflex can begin to act in less than the duration of a cardiac cycle (fractions of a second) and thus baroreflex adjustments are key factors in dealing with postural hypotension , the tendency for blood pressure to decrease on ...
B-type natriuretic peptide (BNP) and its pro hormone NT-proBNP are especially useful in diagnosing heart failure, as their levels in the blood increase along with the severity of the condition. [3] Rapid testing of BNP and NT-proBNP can also help distinguish between shortness of breath due to heart and lung-related causes.
Due to the broad definition of a hormone (as a signaling molecule that exerts its effects far from its site of production), numerous kinds of molecules can be classified as hormones. Among the substances that can be considered hormones, are eicosanoids (e.g. prostaglandins and thromboxanes), steroids (e.g. oestrogen and brassinosteroid), amino ...
The ability of a target cell to respond to a hormone depends on the presence of receptors, within the cell or on its plasma membrane, to which the hormone can bind. Hormone receptors are dynamic structures. Changes in the number and sensitivity of hormone receptors may occur in response to high or low levels of stimulating hormones. Blood ...
Outside the liver, angiotensinogen is picked up from the circulation or expressed locally in some tissues; with renin they form angiotensin I, and locally expressed angiotensin-converting enzyme, chymase or other enzymes can transform it into angiotensin II. [13] [14] [15] This process can be intracellular or interstitial. [10]
Pulsatile secretion is a biochemical phenomenon observed in a wide variety of cell and tissue types, in which chemical products are secreted in a regular temporal pattern. The most common cellular products observed to be released in this manner are intercellular signaling molecules such as hormones or neurotransmitters.
[13] [14] In the heart, this contributes to a decreased heart rate. They do so by the G βγ subunit of the G protein; G βγ shifts the open probability of K + channels in the membrane of the cardiac pacemaker cells, which causes an outward current of potassium, effectively hyperpolarizing the membrane, which slows down the heart rate.
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