Section 5

Question 1

What is the primary reason for the existence of the lymphatic system?

Answer 1

To manage the excess filtered fluid that is not reabsorbed in the capillaries.

Question 2

In a healthy individual, is there more filtration or reabsorption occurring in the capillaries?

Answer 2

there is slightly more filtration occurring than reabsorption.

Question 3

Explain the physiological consequence if the lymphatic system fails to function effectively.

Answer 3

there can be an accumulation of excess filtered fluid in the tissues, leading to edema and disruption of fluid balance

Question 4

What role does the lymphatic system play in preventing edema?

Answer 4

The lymphatic system prevents edema by collecting and transporting excess filtered fluid, ensuring it doesn’t accumulate in the tissues.

Question 5

How much blood flows through the capillaries each day with an average cardiac output of 5 Liters per minute?

Answer 5

approximately 7200 Liters of blood flow through the capillaries each day

Question 6

Discuss the components of the lymphatic system and their specific roles.

Answer 6

The lymphatic system comprises the spleen, thymus, lymph nodes, lymph channels, and the tonsils. Each component plays a specific role in immune function and fluid balance.

Question 7

What are the initial lymphatics?

Answer 7

Initial lymphatics are small, blind-ended lymph vessels found within capillary beds, marking the beginnings of the lymphatic system.

Question 8

How do lymphatic vessels differ from capillaries in terms of their structure?

Answer 8

Lymphatic vessels are composed of a single layer of overlapping endothelial cells, creating one-way valves, unlike capillaries where endothelial cells are joined side-by-side.

Question 9

Explain the function of the one-way valves in lymphatic vessels.

Answer 9

One-way valves in lymphatic vessels prevent backflow by closing when the pressure inside the vessel increases, ensuring fluid does not leave when interstitial pressure is elevated.

Question 10

What role do the initial lymphatics play in preventing the re-entry of large particles like protein or bacteria into capillaries?

Answer 10

The initial lymphatics provide a route for large particles, such as protein or bacteria, to access the lymphatic system and prevent their re-entry into capillaries.

Question 11

Where do larger lymph vessels eventually empty?

Answer 11

Larger lymph vessels eventually empty into the venous system, where the blood enters the right atrium of the heart.

Question 12

How is lymph propelled towards the heart in the absence of a pump in the lymphatic system?

Answer 12

Smooth muscle cells surrounding larger lymph vessels help propel lymph towards the heart, despite the absence of a pump in the lymphatic system.

Question 13

What is one of the primary functions of the lymphatic system in terms of fluid balance?

Answer 13

One of the primary functions of the lymphatic system is to return excess fluid, correcting the imbalance between filtration and reabsorption to prevent the accumulation of fluid in the interstitial space.

Question 14

Describe the role of the lymphatic system in defending the body against disease.

Answer 14

The lymphatic system defends the body against disease by passing through lymph nodes, which contain phagocytes to destroy bacteria and lymphocytes that attack bacteria, viruses, and other causes of illness.

Question 15

What role does the lymphatic system play in the transport of absorbed fat?

Answer 15

The lymphatic system transports absorbed fat from dietary digestion, as the end product of dietary fats is too large to be absorbed into capillaries.

Question 16

Why does protein filtered in the capillaries get taken up by the lymphatic system?

Answer 16

Protein filtered in the capillaries is taken up by the lymphatic system because it cannot re-enter the capillaries, and its accumulation could impact the balance of filtration and reabsorption.

Question 17

If protein allowed to accumulate in the interstitial space, what impact could it have on the balance of filtration and reabsorption?

Answer 17

If protein were allowed to accumulate in the interstitial space, it could impact the balance of filtration and reabsorption to the point that reabsorption could not occur.

Question 18

Your best friend has had a rather serious cold for the past week and now you’re starting to feel under the weather. You feel tired, lethargic, and your throat is sore to touch making it difficult to swallow. From what you have learned about the lymphatic system, why do you think the glands in your neck are swollen when you are sick?

Answer 18

Swollen glands, or swollen lymph nodes, are a sign that the body is fighting off an in infection or illness.
These glands, which are found throughout the body including the neck, have immune cells called
lymphocytes in them. Lymphocytes attack bacteria, viruses, and other things that cause illness. When
the body is trying to rid itself of harmful bacteria / viruses (such is the case when you have a cold), it
makes more lymphocytes which causes swelling in the lymph nodes.

Most of the time, the lymph nodes return to normal size once the harmful bacteria / virus has been
eliminated.

Question 19

What is oedema?

Answer 19

Edema is the swelling of tissues caused by the accumulation of interstitial fluids.

Question 20

How does a reduced concentration of plasma proteins contribute to the development of edema?

Answer 20

A reduced concentration of plasma proteins decreases plasma-colloid osmotic pressure, resulting in greater filtration forces and lesser reabsorption forces. The net result is edema.

Question 21

Explain how increased permeability of capillary walls could lead to edema.

Answer 21

Increased permeability of capillary walls can cause edema by allowing the filtering of plasma proteins into the interstitial space, increasing interstitial fluid colloid osmotic pressure and favoring filtration. This occurs in allergic reactions and insect bites.

Question 22

What happens in the scenario of increased venous pressure that can result in edema?

Answer 22

Increased venous pressure, due to an abnormality preventing normal venous drainage, increases capillary blood pressure, leading to net filtration and edema. This commonly occurs in conditions like heart failure.

Question 23

How does the blockage of lymph vessels contribute to the occurrence of edema?

Answer 23

Blockage of lymph vessels prevents the proper removal of excess interstitial fluids and proteins, resulting in edema. The lymphatic system’s inability to drain leads to fluid accumulation in the tissues.

Question 24

What is lymphatic filariasis, and why does it lead to oedema?

Answer 24

Lymphatic filariasis, also known as elephantiasis, is a tropical condition caused by a mosquito-borne parasitic worm that invades the lymph vessels. The interference with lymph drainage, particularly in the extremities, results in gross oedema, giving affected body parts an elephant-like appearance.