Lymphatic system

Question 1

What’s the lymphatic system?

Answer 1

The lymphatic system is a network of drainage tubes, connected to lymph glands which act as drainage channels for the body’s tissues

Question 2

Name 2 characteristics of lymphatic capillaries

Answer 2

Lymphatic capillaries have no smooth muscle.

Lymphatic capillaries are blind (closed) ended

Question 3

Why are lymphatic capillaries closed ended?

Answer 3

So interstitial fluid can flow into the capillaries but not out

Question 4

Name 2 characteristics of the collecting vessels

Answer 4

Collecting vessels have smooth muscle coverage.

Collecting vessels have luminal valves

Question 5

Describe the process of lymph drainage

Answer 5

Lymph drainage begins with absorption of fluid from the tissues. Lymph is transported through larger collecting vessels to lymph nodes, which filter the lymph where there is also interaction with the immune system. After passing through a series of lymph nodes, large lymph vessels eventually discharge into the great veins of the neck.

Question 6

What is lymph?

Answer 6

Lymph is interstitial fluid containing salts, proteins and cells, originally formed from a plasma ultrafiltrate.

Question 7

What are the 2 main functions of lymph glands (filter stations positioned at intervals along the lymph drainage route)?

Answer 7

1) To clean up the lymph before it re-enters the blood stream, by sieving out, trapping and destroying foreign materials.
2) Monitoring the lymph for tell-tale signs of predators (e.g. pathogens), and therefore playing an important role in immune response

Question 8

What is chronic oedema?

Answer 8

Long-term lymphatic failure

Question 9

What are the 2 possible causes of chronic oedema?

Answer 9

1) The lymph drainage is insufficient

2) The lymph load exceeds the capacity

Question 10

What’s the difference between relative and absolute lymphatic failure?

Answer 10

Relative lymphatic failure is where there’s lymphatic failure, but capillary filtration increases, so it’s less serious. Absolute lymphatic failure has no increase in capillary filtration

Question 11

What is a venous oedema?

Answer 11

High lymph load from venous hypertension overwhelming lymph drainage

Question 12

What is a common complication of impaired lymph drainage? (consider the functions of the lymphatic system)

Answer 12

Infection can ensue, e.g. cellulitis, because the lymphatic system houses the immune system and is responsible for immune cell trafficking

Question 13

The lymphatic system is also involved in fat homeostasis. What 2 processes is it responsible for?

Answer 13

Gut fat absorption and peripheral fat resorption

Question 14

The lymphatic system is majorly responsible for metastasis. What is the name of the process designed to detect lymphatic spread of cancer and guide treatment?

Answer 14

A sentinel node biopsy