Simply put, this happened because the urine vacated or left the body with velocity; thereby, lowering the pressure which in turn relieved the discomfort the person was feeling. Gas: you breathe in very deeply; you feel your lungs fill with air. That feeling of fullness is the high pressure being felt on the lung walls. Simply put, this relief or lowering of pressure happened because the air vacated the body with velocity. Try it and experiment with in taking air slowly and quickly; thereby, changing the fluid's velocity, pay attention to how your lungs feel or perceive pressure as you breathe in and out.
To this end, have you noticed that when you exercise, that your blood pressure increases then it will level out even though your body is at work? That is because your blood will flow at an increased rate velocity to lower the pressure on the vein walls and will do so just enough to keep the system going at the pace of work, it is undertaking. It operates as a self-regulating system of balance and it is only achieved with a low to high or high to low exchange.
In fluid physics, most systems try to find a natural balance between the object such as the bladder, lungs hose, balloon, container, tube, etc. Now you may be wondering, why blood in veins has a higher velocity as compared to capillaries. That answer comes down to the work of the veins in comparison to the work of the capillaries. Important Solutions 1. Question Bank Solutions Concept Notes Time Tables. Advertisement Remove all ads.
Why is the velocity of blood flow the lowest in the capillaries? In blood vessels, most of the resistance is due to vessel diameter. As vessel diameter decreases, the resistance increases and blood flow decreases. Very little pressure remains by the time blood leaves the capillaries and enters the venules. Blood flow through the veins is not the direct result of ventricular contraction. Instead, venous return depends on skeletal muscle action, respiratory movements, and constriction of smooth muscle in venous walls.
Pulse refers to the rhythmic expansion of an artery that is caused by ejection of blood from the ventricle. It can be felt where an artery is close to the surface and rests on something firm. The measures of blood pressure also change in response to stress, nutritional factors, drugs, or disease.
The body regulates blood pressure by changes in response to the cardiac output and stroke volume. Cardiac output is the volume of blood pumped by the heart in one minute. It is calculated by multiplying the number of heart contractions that occur per minute heart rate times the stroke volume the volume of blood pumped into the aorta per contraction of the left ventricle.
Therefore, cardiac output can be increased by increasing heart rate, as when exercising. However, cardiac output can also be increased by increasing stroke volume, such as if the heart were to contract with greater strength.
Stroke volume can also be increased by speeding blood circulation through the body so that more blood enters the heart between contractions. During heavy exertion, the blood vessels relax and increase in diameter, offsetting the increased heart rate and ensuring adequate oxygenated blood gets to the muscles.
Stress triggers a decrease in the diameter of the blood vessels, consequently increasing blood pressure. These changes can also be caused by nerve signals or hormones; even standing up or lying down can have a great effect on blood pressure. Privacy Policy. Skip to main content. The Circulatory System. Search for:. Blood Flow and Blood Pressure Regulation. Blood Flow Through the Body The heart pumps oxygenated and deoxygenated blood throughout the body in a complex system of arteries, veins, and capillaries.
Learning Objectives Explain the blood flow through the body.
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