The variables affecting blood flow and blood pressure in the systemic circulation are cardiac output, compliance, blood volume, blood viscosity, and the length and diameter of the blood vessels. … In the arterial system, as resistance increases, blood pressure increases and flow decreases.
Which factor has the greatest effect on blood flow?
The three most important factors affecting resistance are blood viscosity, vessel length and vessel diameter and are each considered below. Blood viscosity is the thickness of fluids that affects their ability to flow.
Which variable has the strongest effect on fluid flow?
Viscosity has a greater effect on fluid flow than vessel radius. Vessel radius has a greater effect on fluid flow than viscosity.
What has the greatest effect on blood viscosity?
Increasing red cell hematocrit increases relative viscosity. Note that the increase is non-linear; increased hematocrit causes a disproportionate increase in relative viscosity. Therefore, blood viscosity strongly depends on hematocrit. At a normal hematocrit of 40%, the relative viscosity of blood is about 4.
Which of the following can cause an increase in blood flow?
Any factor that causes cardiac output to increase, by elevating heart rate or stroke volume or both, will elevate blood pressure and promote blood flow. These factors include sympathetic stimulation, the catecholamines epinephrine and norepinephrine, thyroid hormones, and increased calcium ion levels.
What happens to the body when blood flow is interfered?
Nicotine causes your blood vessels to constrict or narrow, which limits the amount of blood that flows to your organs. Over time, the constant constriction results in blood vessels that are stiff and less elastic. Constricted blood vessels decrease the amount of oxygen and nutrients your cells receive.
What are the three important sources of resistance to blood flow?
There are three primary factors that determine the resistance to blood flow within a single vessel: vessel diameter (or radius), vessel length, and viscosity of the blood. Of these three factors, the most important quantitatively and physiologically is vessel diameter.
Which blood vessels experience the sharpest decrease in blood pressure?
The greatest drop in blood pressure occurs at the transition from arteries to arterioles. Primary function of each type of blood vessel: Arterioles have a very small diameter (<0.5 mm), a small lumen, and a relatively thick tunica media that is composed almost entirely of smooth muscle, with little elastic tissue.
Why pressure changes are not the best way to control blood flow?
Pressure changes are not the best way to control blood flow because it could place more stress on the heart (which causes the initial pressure) and requires the heart to change its force of contraction. The blood vessels need time to respond to that change in force as well as the large arteries around the heart.
Which blood vessels handle the highest blood pressure?
Arteries carry blood away from your heart. Arteries have thick walls so they can handle the high pressure and velocity that expels your blood out of your heart. Veins carry blood back to your heart from the rest of your body.
What has the greatest effect on peripheral resistance?
Peripheral resistance is determined by three factors: Autonomic activity: sympathetic activity constricts peripheral arteries. Pharmacologic agents: vasoconstrictor drugs increase resistance while vasodilator drugs decrease it. Blood viscosity: increased viscosity increases resistance.
Which of the following has a directly proportional effect on blood flow?
Which of the following is directly proportional to blood flow? pressure changes.
What is the driving force for blood flow?
Mean arterial pressure is the force that drives the flow of blood through the circulatory system.
What is the largest artery in the body?
Aorta Anatomy
The aorta is the large artery that carries oxygen-rich blood from the left ventricle of the heart to other parts of the body.
Which are major classes of blood vessels?
There are three main types of blood vessels:
- Arteries. They carry oxygen-rich blood away from the heart to all of the body’s tissues. …
- Capillaries. These small blood vessels connect the arteries and the veins. …
- Veins. These are blood vessels that take blood back to the heart.
Where are Sinusoids found within the body?
Sinusoids are a special type of capillary that have a wide diameter. These are found in the liver, spleen, lymph nodes, bone marrow and some endocrine glands. They can be continuous, fenestrated, or discontinuous.