What is meant by blood pressure?Is this pressure same in cell blood vessels? How systallic pressure differs from diastolic pressure
Answers
BLOOD PRESSURE: is defined as the pressure used by the heart to pump blood throughout the body
This pressure will stay the same, but the velocity might decrease
systallic pressure and diastolic pressure difference is listed below :
Answer:
The systolic blood pressure is defined as the maximum pressure experienced in the aorta when the heart contracts and ejects blood into the aorta from the left ventricle (approximately 120 mmHg). The diastolic blood pressure is the minimum pressure experienced in the aorta when the heart is relaxing before ejecting blood into the aorta from the left ventricle (approximately 80 mmHg). Normal pulse pressure is, therefore, approximately 40 mmHg.
A change in pulse pressure (delta Pp) is proportional to volume change (delta V) but inversely proportional to arterial compliance (C):
Delta Pp = Delta V/C
Because the change in volume is due to the stroke volume of blood ejected from the left ventricle (SV), we can approximate pulse pressure as:
Pp = SV/C
A normal young adult at rest has a stroke volume of approximately 80 mL. Arterial compliance is approximately 2 mL/mm Hg, which confirms that normal pulse pressure is approximately 40 mm Hg.
Arterial compliance is equal to the change in volume (Delta V) over a given change in pressure (Delta P):
C = Delta V/Delta P
Because the aorta is the most compliant portion of the human arterial system, the pulse pressure is the lowest. Compliance progressively decreases until it reaches a minimum in the femoral and saphenous arteries, and then it begins to increase again. This concept requires an understanding of the effect of pressure wave reflection on amplification of aortic pressure and thus pulse pressure. The phenomenon mainly occurs in the lower body, especially the lower extremities where pressure waves reflect back due to vessel branching, and the vessels are less compliant (stiffer) When a reflected wave is in phase with a forward wave, it generates a wave with higher amplitude. An analogy here is waves bouncing off a seawall and interacting with an incoming wave. If they are in phase, the wave height is greater.
A pulse pressure that is less than 25% of the systolic pressure is inappropriately low or narrowed, whereas a pulse pressure of greater than 100 is high or widened.
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Cellular
Arteries are efferent vessels that lead away from the heart. They are lined by endothelial cells and consist of three different layers, which appears in the figure below. The innermost layer, the tunica intima, consists primarily of an endothelial layer, subendothelial layer, and an internal elastic lamina. The middle layer, also called the tunica media, has concentric layers of helically arranged smooth muscle cells, as well as varying amounts of elastic and reticular fibers and proteoglycans. Some of the larger arteries also contain an external elastic lamina. Finally, the tunica adventitia, also called the tunica externa, is the outermost layer made up of longitudinally oriented type-I collagen fibers.
There are two main types of arteries in the human body. The first, which is the more prominent of the two, is the muscular artery. Muscular arteries have a thin intimal layer with a well-developed internal elastic lamina. They also have a muscular wall that can be up to forty layers thick. The primary function of these arteries is to regulate blood flow through adjustment of blood vessel caliber. The other main type of artery is the elastic artery. Elastic arteries are unique as they have elastic fibers interspersed in between the smooth muscle cells of the tunica intima, which allows elastic arteries to store kinetic energy to smooth out the surge in blood pressure that occurs during systole, known as the Windkessel effect.
Explanation: