CFR 3 Notes

This set of flashcards covers the key concepts and details related to the cardiovascular and lymphatic systems, fluid exchange processes, and related physiological functions.

What is the main physiological function of the lymphatic system?

To collect and return interstitial fluid to the blood vascular system.

What are the three main functions of the lymphatic system?

1. Collect and return interstitial fluid; 2. Mount immune responses; 3. Absorb lipids from the gastrointestinal tract.

What is the significance of negative interstitial fluid pressure?

It helps maintain fluid equilibrium and prevents excessive fluid return to the capillaries.

What does the term 'oedema' refer to?

Excess interstitial fluid in tissues leading to swelling.

What causes increased interstitial fluid pressure and potentially leads to oedema?

1. Increased capillary pressure; 2. Decreased plasma proteins; 3. Lymphatic obstruction; 4. Increased capillary permeability.

How does capillary hydrostatic pressure change from arterial to venous ends?

It decreases from +25 mmHg at the arterial end to +10 mmHg at the venous end.

What is the balance of hydrostatic and osmotic pressures critical for?

It is critical for fluid exchange in capillaries.

How much fluid is ultrafiltered through the blood capillary network per minute?

20 mL/min.

What percentage of the gross ultrafiltrate is reabsorbed in the venous capillaries?

About 90%.

What happens to the remaining 10% of the gross ultrafiltrate?

It passes into the lymphatic system as net ultrafiltrate.

Describe the structure of lymphatic vessels.

They are similar to blood capillaries but end blindly and have a thin, permeable endothelium with overlapping cells forming non-return valves.

What role do lymph nodes play in the lymphatic system?

They filter out bacteria and foreign particles using lymphocytes and macrophages.

What are Peyer's patches?

They are specialized lymph nodes found in the gut.

What is the cisterna chyli?

A large sac in the abdomen that drains lymph from the lower body and left upper body into the thoracic duct.

Where does lymph from the right upper body drain into?

Into the right lymphatic duct, which joins the venous system at the right subclavian and right jugular veins.

What is the average lymph flow during rest?

About 120 mL/hour.

What kind of pressure does the plasma colloid osmotic pressure exert?

A negative force that draws fluid into capillaries.

What can cause a decrease in plasma protein levels?

Conditions like severe burns or nephritis that cause loss of albumin.

What is the effect of mechanical pressure on filtration?

It can overcome colloidal osmotic pressure, facilitating fluid movement from capillaries.

How does exercise affect lymph flow?

It can increase lymph flow by five to fifteen times due to muscle contraction.

What is the composition of lymphatic fluid?

It is similar to interstitial fluid and contains proteins, fat droplets, and lymphocytes.

What causes lymphatic obstruction that can lead to oedema?

Conditions such as filariasis leading to protein accumulation in interstitial fluid.

What is the colloidal osmotic pressure of plasma at the venous end of capillaries?

-28.0 mmHg.

What factors can alter the capillary permeability?

Burns or allergic reactions can lead to increased permeability.

Where does oxygenated blood travel in relation to capillaries?

From arterioles to tissue via arterial capillaries.

What is the average interstitial fluid pressure?

-6.3 mmHg.

What happens if interstitial fluid pressure becomes positive?

It can lead to tissue swelling or oedema.

What are the major components of the lymphatic system?

Lymphatic vessels, lymph nodes, and lymph fluid.

How does lymphatic fluid differ from blood plasma?

Lymphatic fluid has a lower protein concentration and contains fat droplets from the gastrointestinal tract.

Why is the lymphatic system not equal on both sides of the body?

Each side has a different drainage pathway, with most drainage occurring via the thoracic duct on the left side.

Where does the thoracic duct collect lymph before returning it to the venous system?

At the junction of the left subclavian and left jugular veins.

What happens to lymph flow during periods of physical rest?

Lymph flow is fairly sluggish.

What type of pressure does interstitial fluid pressure create?

A negative pressure that encourages fluid to enter tissues.

What is the role of macrophages in lymph nodes?

To engulf and destroy bacteria and foreign particles.

How do the values of hydrostatic and osmotic pressure change from the arterial to venous end?

Hydrostatic pressure decreases, while osmotic pressure remains relatively constant.

Which white blood cells are primarily found in lymph nodes?

Lymphocytes and macrophages.

What is the primary reason for protein accumulation in interstitial fluid?

Lymphatic obstruction or increased capillary permeability.

What structures are found in the lymphatic capillaries to prevent backflow?

Non-return valves formed by overlapping endothelial cells.

What are lymph nodes composed of?

Lymphoid tissue rich in lymphocytes.

What is unique about terminal lymphatic capillaries?

They drain excess interstitial fluid and end blindly.

Where does the thoracic duct originate?

From the cisterna chyli in the abdomen.

What is the composition and importance of the lymphatic fluid?

It contains proteins and immune cells, aiding in immune response and fluid balance.