This can occur when someone is
very stressed or has a lot of tightened muscles due to exercise stress
, as can be seen in the adjacent picture. In summary, any increases in cardiac output (HR and/or SV), blood viscosity or total peripheral resistance will result in increases in BP.
How does total peripheral resistance affect cardiac output?
During exercise, the
cardiac output increases more than the total resistance decreases
, so the mean arterial pressure usually increases by a small amount.
How does increased peripheral resistance affect 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.
What has the biggest impact on peripheral resistance?
The last factor affecting resistance is
blood vessel diameter
. This factor is the most variable of the three and has the greatest impact on resistance. … So the peripheral blood vessels dilate to increase blood flow to the limbs.
Does total peripheral resistance increase as blood viscosity increases?
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.
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 and heart rate when arterial resistance is increased?
Cardiac output is a function of heart rate and stroke volume.
If the pressure in a vessel increases then the blood flow will increase
. However, if the resistance in a vessel increases then the blood flow will decrease.
What are the three main factors that influence peripheral resistance?
back | nextPeripheral 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.
What happens when total peripheral resistance decreases?
The decrease in total peripheral resistance is the result of
decreased vascular resistance in skeletal muscle vascu- lar beds, leading to increased blood flow
. The increase in blood flow to cardiac and skeletal muscle produced by exercise is called exercise hyperemia.
What is total peripheral resistance TPR determined by?
Total peripheral resistance (TPR) is determined as
the quotient of ModelFlow-derived MAP divided by CO.
TPR
est
was obtained as the quotient of mean arterial pressure in millimeters of mercury (mmHg) divided by cardiac output in liters per minute (L/min) [Equation 2].
What factors affect blood flow and pressure?
Four major factors interact to affect blood pressure:
cardiac output, blood volume, peripheral resistance, and viscosity
. When these factors increase, blood pressure also increases. Arterial blood pressure is maintained within normal ranges by changes in cardiac output and peripheral resistance.
Which circuit has the greatest peripheral resistance?
Total peripheral resistance is the combined resistances of all the blood vessels within the systemic circuit. The greatest amount of resistance comes from
arterioles
and small arteries and these are called resistance vessels.
What causes increased peripheral vascular resistance?
Peripheral vascular resistance (systemic vascular resistance, SVR) is the resistance in the circulatory system that is used to create blood pressure, the flow of blood and is also a component of cardiac function.
When blood vessels constrict (vasoconstriction)
this leads to an increase in SVR.
What happens when blood viscosity increases?
Although it is commonly accepted that sustained hyperviscosity can decrease perfusion and increase blood pressure, it should be noted that increased blood viscosity has two effects in the cardiovascular system:
it may act to increase shear stress on the endothelium and increase NO release, promoting vasodilation as
…
How does blood viscosity affect resistance?
Blood Viscosity
The viscosity of blood is
directly proportional to resistance and inversely proportional to flow
; therefore, any condition that causes viscosity to increase will also increase resistance and decrease flow.
What is the normal range for blood viscosity?
Blood is a non-Newtonian, shear thinning fluid with thixotropic and viscoelastic properties. Many cardiovascular handbooks consider blood viscosity values
between 3.5 and 5.5 cP
to be normal.
