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In a normal circulatory system, the volume of blood returning to the heart each minute is approximately equal to the volume that is pumped out each minute (the cardiac output). [12] Because of this, the velocity of blood flow across each level of the circulatory system is primarily determined by the total cross-sectional area of that level.
Any object, totally or partially immersed in a fluid or liquid, is buoyed up by a force equal to the weight of the fluid displaced by the object. Archimedes' principle allows the buoyancy of any floating object partially or fully immersed in a fluid to be calculated. The downward force on the object is simply its weight.
Any body wholly or partially immersed in a fluid experiences an upward force equal to the weight of the fluid displaced. In addition to the principle that bears his name, Archimedes discovered that a submerged object displaces a volume of water equal to the object's own volume (upon which the story of him shouting "Eureka" is based). This ...
Blood viscosity is a measure of the resistance of blood to flow. It can also be described as the thickness and stickiness of blood. This biophysical property makes it a critical determinant of friction against the vessel walls, the rate of venous return, the work required for the heart to pump blood, and how much oxygen is transported to tissues and organs.
Also called Dalton's law of partial pressure, and related to the ideal gas laws, this empirical law was observed by John Dalton in 1801. Darcy's law, in hydrogeology, describes the flow of a fluid (such as water) through a porous medium (such as an aquifer). Davis's law, in anatomy, describes how soft tissue models along imposed demands.
In arthropods, the open circulatory system is a system in which a fluid in a cavity called the hemocoel or haemocoel bathes the organs directly with oxygen and nutrients, with there being no distinction between blood and interstitial fluid; this combined fluid is called hemolymph or haemolymph. [28]
Vascular resistance occurs when the vessels away from the heart oppose the flow of blood. Resistance is an accumulation of three different factors: blood viscosity, blood vessel length and vessel radius. [30] Blood viscosity is the thickness of the blood and its resistance to flow as a result of the different components of the blood.
Archimedes' principle - Ignoring the minor effect of surface tension, an object, wholly or partially immersed in a fluid, is buoyed up by a force equal to the weight of the fluid displaced by the object. Thus, when in water, the weight of the volume of water displaced as compared to the weight of the diver's body and the diver's equipment ...