Chapter 16: The Microcirculation and Lymphatic System

The average interstitial hydrostatic pressure is _____ mmHg.

-3

About _____% of the fluid filtered from the arterial end of the capillary enters the lymphatic system; the other _____% is reabsorbed on the venous end.

10, 90

The average functional capillary hydrostatic pressure is _____ mmHg.

17.3

The normal rate of net filtration in the body (excluding kidneys) is only about _____ mL/min.

2

The total estimated lymph flow per day is _____ L.

2-3

The average colloid osmotic pressure of plasma is _____ mmHg.

28

The average colloid osmotic pressure of interstitial fluid is _____ mmHg.

8

The rate of water diffusion through the capillary membrane is around _____ times greater than the rate plasma flows linearly along the capillary.

80

Capillary lymphatic endothelial cells contain a few _____ filaments that may contribute to initial lymph pumping.

Actomyosin

The biggest contributor to plasma colloid osmotic pressure is _____, followed less so by _____. _____ contributes very little to this pressure.

Albumin (80%), globulins (20%), fibrinogen

Endothelial cells of lymphatic capillaries are attached to surrounding connective tissue by _____.

Anchoring filaments

The combination of proteoglycan filaments in the _____ of interstitium and the entrapped interstitial fluid is called _____.

Brush pile, tissue gel

The _____ is a measure of the capacity of a capillary membrane to filter water for a given net filtration pressure.

Capillary filtration coefficient (Kf)

The whole-body _____, calculated by dividing the net filtration rate by the net filtration pressure, equals _____ mL/min/mmHg.

Capillary filtration coefficient (Kf), 6.67

The four Starling forces acting at the capillary membrane are _____, _____, _____ and _____.

Capillary hydrostatic pressure, interstitial fluid hydrostatic pressure, plasma colloid osmotic pressure, interstitial fluid colloid osmotic pressure

_____ are small plasmalemma vesicles formed from protein _____, cholesterol, and sphingolipids, which play a role in endocytosis and transcytosis of macromolecules across endothelial cells.

Caveolae, caveolins

The structure of the interstitium has two main components: _____ fiber bundles, and _____ filaments.

Collagen, proteoglycan

Plasma and interstitial proteins are responsible for producing the _____.

Colloid osmotic pressure (oncotic pressure)

As blood flows through a capillary, there is _____ mixing of the interstitial fluid and plasma; the only dissolved constituents uncapable of readily diffusing are _____.

Continual, proteins

When a lymph vessel is stretched with fluid, its smooth muscle in the vessel wall automatically _____.

Contracts

Rates of _____ across capillaries are so fast, even slight concentration differences allow more than adequate transport.

Diffusion

The _____ describes the additional increase in plasma colloid osmotic pressure due to the association of sodium, potassium, and other ions with plasma proteins (equivalent in magnitude to around _____ mmHg.)

Donnan effect, 9

Any factor increasing _____ pressure also increases lymph flow, up until around 2 mmHg.

Interstitial fluid (hydrostatic)

The two factors determining lymph flow are _____ and activity of the _____.

Interstitial fluid pressure, lymphatic pump

The lower hydrostatic pressure on the venous end of a capillary results in an _____ net filtration pressure.

Inward (negative)

The thoracic duct drains into the junction between the _____ subclavian vein and internal jugular vein.

Left

As a general rule, the normal interstitial fluid pressure is usually several mmHg _____ than that of the surrounding pressure.

Less (lower)

_____-soluble substances, such as oxygen and carbon dioxide, diffuse directly through cell membranes of capillaries; _____-soluble substances, such as sodium, chloride, and glucose, must diffuse through the intercellular pores.

Lipid, water

Protein concentration of lymph from the _____ and _____ are much higher than the average 2 g/dL of ordinary lymph tissue (based on their function).

Liver, intestines

The process of _____ accounts for the slightly negative pressure of interstitial spaces.

Lymphatic pumping

If the sum of Starling forces, also known as the _____, is positive, a net fluid _____ will occur across the capillary. If the sum is negative, a net fluid _____ will occur.

Net filtration pressure (NFP), filtration, absorption

The higher hydrostatic pressure at the arterial end of the capillary results in an _____ net filtration pressure.

Outward (positive)

When the rate of _____ usage of a tissue is great, intermittent periods of capillary blood flow occur more often.

Oxygen

Capillaries in various tissues have vast differences in _____ according to the function of the tissue there.

Permeability

The _____ emerges from a capillary's origin at a metarteriole and can open/close the entrance to the capillary.

Precapillary sphincter

Interstitial fluid contains a higher total _____ of proteins than the plasma, but due to interstitial fluid's much higher volume, the _____ of proteins is lower.

Quantity (mass), concentration

When tissues develop edema, small pockets of free fluid known as _____ expand tremendously within the interstitium.

Rivulets

Most water-soluble molecules and small ions rapidly diffuse through _____ between endothelial cells.

Slit pores (intercellular clefts)

Inward-flapping lymphatic _____ allow inflow of interstitial fluid, but prevent its backflow from the vessel.

Valves

Blood flows through capillaries intermittently, a phenomenon called _____ that is due to contraction of _____ and _____.

Vasomotion, metarterioles, precapillary sphincters