Which Has The Greatest Effect On Peripheral Resistance?

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Arterioles have the most increase in resistance and cause the largest decrease in blood pressure. The constriction of arterioles increases resistance, which causes a decrease in blood flow to downstream capillaries and a larger decrease in blood pressure.

Where is the main control of peripheral resistance?

The central dictation of peripheral vascular resistance occurs at the level of the arterioles. The arterioles dilate and constrict in response to different neuronal and hormonal signals.

What has the greatest impact on peripheral resistance to blood flow?

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.

What two factors will increase blood flow?

It is by elevation of stroke volume or heart rate or both. This will increase the blood pressure and enhance the flow of blood. Such factors are sympathetic stimulation, the catecholamines norepinephrine and epinephrine, increased levels of calcium ions, and thyroid hormones.

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.

What happens when peripheral resistance increases?

Peripheral resistance is the resistance of the arteries to blood flow. As the arteries constrict, the resistance increases and as they dilate, resistance decreases. Peripheral resistance is determined by three factors: Autonomic activity: sympathetic activity constricts peripheral arteries.

How do you reduce peripheral resistance?

ACE inhibitors reduce total peripheral resistance by blocking the actions of ACE, the enzyme that converts angiotensin I to angiotensin II (Fig. 8-5). Recall that angiotensin II is a potent vasoconstrictor and stimulates release of aldosterone from the adrenal cortex, which causes sodium and water retention.

What happens to blood pressure when peripheral resistance decreases?

In cardiovascular terms this is known as ‘total peripheral resistance’ (TPR). If the area available for blood to flow through is reduced then pressure will increase.

What is the relationship between blood flow pressure and resistance?

In the arterial system, as resistance increases, blood pressure increases and flow decreases. In the venous system, constriction increases blood pressure as it does in arteries; the increasing pressure helps to return blood to the heart.

Where is blood flow the fastest?

This value is inversely related to the total cross-sectional area of the blood vessel and also differs per cross-section, because in normal condition the blood flow has laminar characteristics. For this reason, the blood flow velocity is the fastest in the middle of the vessel and slowest at the vessel wall.

What happens to the body when blood flow is interfered?

In a heart attack (or myocardial infarction), the heart muscle becomes damaged by lack of oxygen, and unless blood flow returns within minutes, muscle damage increases and the heart’s ability to pump blood is compromised. If the clot can be dissolved within a few hours, damage to the heart can be reduced.

What has the greatest effect on blood pressure?

The pressure is greatest when blood is pumped out of the heart into the arteries. When the heart relaxes between beats (blood is not moving out of the heart), the pressure falls in the arteries.

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Which blood vessels is blood pressure the highest?

Explanation: In the general circulation, the highest blood pressure is found in the aorta and the lowest blood pressure is in the vena cava. As this suggests, blood pressure drops in the general circulation as it goes from the aorta to the rest of the body.

What influences total peripheral resistance?

Three main sources of peripheral resistance: Blood vessel diameter, blood viscosity, and total vessel length. If arteries lose their elasticity and become more rigid, blood pressure increases.

Why is peripheral resistance important?

The total resistance to blood flow through peripheral vascular beds has an important influence on the cardiac output. A rise in total peripheral re sistance raises arterial blood pressure which, in turn, tends to reduce the cardiac output (1). A fall in total peripheral resistance does the reverse.

Which is the most important organ of peripheral vascular resistance?

The major regulator of vascular resistance in the body is regulation of vessel radius. In humans, there is very little pressure change as blood flows from the aorta to the large arteries, but the small arteries and arterioles are the site of about 70% of the pressure drop, and are the main regulators of SVR.

Which of the following will decrease peripheral resistance?

Which of the following would decrease peripheral resistance to blood flow? … –Decreased blood pressure. This is due to increased sodium in the blood, triggering sodium receptors in the vasomotor center to decrease sympathetic stimulation of blood vessels.

What happens to blood pressure if your blood is thicker?

The relationship between BP and viscosity is such that, given a constant systolic BP, if blood viscosity increases, then the total peripheral resistance (TPR) will necessarily increase, thereby reducing blood flow. Conversely, when viscosity decreases, blood flow and perfusion will increase.

Does increased peripheral resistance increase blood pressure?

Blood pressure increases with increased cardiac output, peripheral vascular resistance, volume of blood, viscosity of blood and rigidity of vessel walls. Blood pressure decreases with decreased cardiac output, peripheral vascular resistance, volume of blood, viscosity of blood and elasticity of vessel walls.

Which of the following could cause an increase in peripheral resistance?

Which of the following could cause an increase in peripheral resistance in the blood vessel? You correctly answered: atherosclerosis.

Which is the major source of resistance to blood flow?

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.

What is the most significant source of blood flow resistance?

The correct answer is option (c) blood viscosity. Blood viscosity is the most significant source of blood flow resistance.

What is the resistance of blood?

These results showed that the average resistance of normal blood at 60° F. measured by Kohlrausch’s method in the apparatus used amounted to 550 ohms, while the specific resistance was 93.5 ohms.

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