Blood Pressure Along the Vascular Circuit
Pressure Along the Vascular Circuit
Systemic Circulation
Artery: 95 mmHg
Arteriole: 60 mmHg
Capillary: 25 mmHg
Venule: 15 mmHg
Vein: 15-3 mmHg
Pulmonary Circulation
Artery: 15 mmHg
Capillary: 10 mmHg
Vein: 5 mmHg
Pressure in systemic circulation are higher than those in pulmonary circulation.
High-pressure system includes
Systemic arteries
Systemic arterioles
Left ventricle in its contracted state
Low-pressure system includes
All the remaining part of the circuit, including pulmonary circulation
Left ventricle in its relaxed state
Relation Between Resistance and Pressure
Pressure drop at any level depends on resistance at that level.
The more the resistance → the more the pressure drop.
Arterioles provide the greatest resistance → greatest pressure drop occurs at arterioles.
Why capillaries do not provide greater resistance in spite of having a smaller diameter?
Answer: Because capillaries are large in number → total cross-section area of all capillaries combined is larger than that of arterioles → capillaries provide lesser resistance.