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Circulation V. Veins Regulation of Arterial Blood Pressure

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Page 1: Circulation V. Veins Regulation of Arterial Blood Pressure

Circulation V.

Veins

Regulation of Arterial Blood Pressure

Page 2: Circulation V. Veins Regulation of Arterial Blood Pressure

Veins.

• Blood flows from the capillaries into the venules, small veins, large veins and into the right atrium.

• Some exchange of molecules occurs between the venules and the interstitial fluid.

• Most of the blood is in the veins.

• Blood reservoir.

Page 3: Circulation V. Veins Regulation of Arterial Blood Pressure
Page 4: Circulation V. Veins Regulation of Arterial Blood Pressure
Page 5: Circulation V. Veins Regulation of Arterial Blood Pressure

• The force driving the blood in the veins is the pressure difference between peripheral veins (5-10 torr) and the right atrium (0 torr).

• Veins are low resistance high capacitance (=compliance) vessels.

• Valves in veins allow flow in one direction.

Page 6: Circulation V. Veins Regulation of Arterial Blood Pressure
Page 7: Circulation V. Veins Regulation of Arterial Blood Pressure

Venous Valves

Page 8: Circulation V. Veins Regulation of Arterial Blood Pressure

• Walls contain smooth muscle innervated by sympathetic nerves that release NE.

• NE causes venoconstriction.

• Skeletal muscle pump.• Respiratory pump.

Page 9: Circulation V. Veins Regulation of Arterial Blood Pressure

Arterial Blood Pressure Regulation.

• Mean arterial blood pressure (MAP) has to be regulated to insure proper blood flow to tissues.

• High MAPtissue damage.• Low MAP poor tissue perfusion. • MAP = CO x TPR• TPR = total peripheral resistance

(sum of resistances of arterioles)

Page 10: Circulation V. Veins Regulation of Arterial Blood Pressure

MAP = CO x TPR

Page 11: Circulation V. Veins Regulation of Arterial Blood Pressure

• MAP = CO x TPR.• CO determines the rate at

which blood goes into the art. system.

• TPR determines the rate at which blood leaves the art. system.

• MAP depends on volume of blood in the art. system.

Page 12: Circulation V. Veins Regulation of Arterial Blood Pressure

Baroreceptor Reflex.

Page 13: Circulation V. Veins Regulation of Arterial Blood Pressure

Arterial Baroreceptors

• Pressure receptors (stretch receptors).

• When blood pressure goes up the receptors are stretched and fire APs.

Page 14: Circulation V. Veins Regulation of Arterial Blood Pressure

Carotid Sinus and Aortic Arch Receptors.

Page 15: Circulation V. Veins Regulation of Arterial Blood Pressure

Effects of Gravity.

Page 16: Circulation V. Veins Regulation of Arterial Blood Pressure
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Page 18: Circulation V. Veins Regulation of Arterial Blood Pressure