Physiology Module 7: Circulation, Blood Flow, and Microcirculation

What is the pressure at the arteriolar end of capillaries?

35 mmHg

What is the pressure at the venous end of capillaries?

10 mmHg

What is the central venous pressure?

0 mmHg

What factors determine blood flow?

Pressure difference at the two ends of a vessel and vascular resistance.

What are the two types of blood flow?

Laminar (streamline) flow and turbulent flow.

What is pulse in terms of circulation?

A new surge of blood in a vessel each time the heart beats.

What is pulse pressure?

The difference between systolic and diastolic pressure.

What are the two major factors affecting pulse pressure?

Stroke volume output of the heart and total distensibility of the arterial tree.

What is microcirculation?

Circulation with vessels of less than 100 micra in diameter.

What is the structure of the capillary membrane?

Porous for passing fluid between plasma and the interstitium.

What is interstitial fluid (ISF)?

Fluid present in the interstitium, outside the capillary.

What is the value of plasma colloid osmotic pressure (PCOP)?

28 mmHg

What is the effect of capillary pressure (CP) on fluid movement?

Outward movement of fluid from blood capillary to ISF.

What causes interstitial edema?

Accumulation of fluid in the interstitial space due to factors like elevated capillary pressure.

What is venous return?

The amount of blood returning to the heart through veins.

What is cardiac output?

The amount of blood pumped out of the heart to the major arteries.

What does the Frank-Starling Law state?

Within physiological limits, whatever amount of blood enters the heart is the same amount pumped out.

What is cardiac failure?

The failure of the heart to pump out blood, classified as compensated vs. decompensated.

What is circulatory shock?

Generalized inadequate blood flow through the body leading to tissue damage due to low O2 and nutrient supply.

What is the pressure in the aorta during systole?

120 mmHg

What is the pressure in the aorta during diastole?

80 mmHg

What is the role of arterioles in circulation?

They act as control valves releasing blood into capillaries.

What are the key characteristics of arteries?

Transport blood under high pressure, carry nutrients, and have strong vascular walls.

What is the function of capillaries?

Two-way diffusion for the exchange of fluid, nutrients, electrolytes, and hormones.

What are venules?

They collect blood from capillaries and gradually coalesce into larger veins.

What is the function of veins in circulation?

Return blood from venules to the heart and serve as blood reservoirs.

What is the significance of interstitial colloid osmotic pressure (ISCOP)?

It promotes outward movement toward ISF.