Principles of lymphatic system

Question 1

What is the function of the lymphatic system?

Answer 1

The lymphatic system is a transport system that aids in fluid return to the venous system and is complementary to the blood vascular system. It also plays a role in the immune system and the transport of specific fats.

Question 2

What are the components of the lymphatic system?

Answer 2

The components of the lymphatic system include lymphatic fluid, lymphatic vessels, and lymphatic organs such as the red bone marrow, thymus gland, spleen, lymph nodes, and nodules, and tonsils.

Question 3

Where does lymphatic fluid originate from?

Answer 3

Lymphatic fluid originates in tissue capillary beds and is almost identical to interstitial fluid, which is similar to blood plasma.

Question 4

What does lymphatic fluid contain?

Answer 4

Lymphatic fluid contains white blood cells, has a relatively high protein concentration, and is involved in immune responses.

Question 5

What is chyle?

Answer 5

Chyle is a special type of lymphatic fluid that contains fats from intestinal absorption.

Question 6

What are the primary lymphatic organs?

Answer 6

The primary lymphatic organs include the red bone marrow and the thymus gland.

Question 7

What are the secondary lymphatic organs?

Answer 7

The secondary lymphatic organs include the spleen, lymph nodes, and nodules, as well as the tonsils.

Question 8

What is the structure of lymphatic vessels?

Answer 8

Lymphatic vessels are porous blind-ended capillaries that converge to become larger vessels and eventually drain into large veins at the root of the neck, at the venous angle.

Question 9

How are lymphatic capillaries structured?

Answer 9

Lymphatic capillaries are simple endothelial tubes with small valves that prevent backflow. They have a larger number of valves compared to veins. Lymphatic vessels are thinner than veins, and larger vessels have three layers: the tunica intima (endothelium), the tunica media, and the tunica adventitia.

Question 10

What is the function of lymph nodes in lymphatic vessels?

Answer 10

Lymph vessels pass through lymph nodes, which act as filters or traps. Lymph nodes help to filter and remove foreign particles, debris, and pathogens from the lymph fluid.

Question 11

What are the primary lymphatic organs?

Answer 11

The primary lymphatic organs include the red bone marrow, where cell manufacture occurs, and the thymus, where T cell maturation takes place and B cells undergo maturation and differentiation.

Question 12

What are the secondary lymphatic organs?

Answer 12

The secondary lymphatic organs include the spleen, lymph nodes, and lymphatic nodules. They function in cell storage and antigen-dependent activation. Examples of lymphatic nodules include the palatine tonsils in the mouth, which are part of the mucosal associated lymphatic tissue (MALT).

Question 13

What are the roles of the lymphatic system?

Answer 13

The lymphatic system plays multiple roles, including the circulation of fluid by collecting fluid lost from capillary beds and returning it to the venous system. It is also involved in the transport of specific fats in the small intestine and serves as part of the immune system, trapping pathogens in lymph nodes and activating immune responses.

Question 14

Is the lymphatic system a closed system?

Answer 14

No, the lymphatic system is not a closed system like the circulatory system.

Question 15

How do lymphatic vessels compare to veins in structure?

Answer 15

Lymphatic vessels are structurally similar to veins. They have relatively thin walls and carry lymph under low pressure. Larger lymphatic vessels have valves to prevent the backflow of lymph under the influence of gravity.

Question 16

How are fats transported in the lymphatic system?

Answer 16

In the small intestine, larger chain fatty acids are coated with protein and packaged with cholesterol to form chylomicrons. Lymph capillaries in this region are called lacteals. The fluid that carries these fats is opaque and milky and is known as chyle.

Question 17

What is the role of the lymphatic system in immune function?

Answer 17

The lymphatic system is critical in immune responses. Lymph nodes, of which there are approximately 600 in the body, trap and process pathogens, activating specific immune responses. Other specific organs involved in immune function include the red bone marrow, thymus, spleen, lymph nodes, and lymph nodules.

Question 18

What is the function of red bone marrow?

Answer 18

Red bone marrow contains active hematopoietic cells, where blood cells are formed. In children, it is found in the medullary cavity, while in adults, it occupies the spaces of spongy bone. It contains specialized blood vessels called sinusoids, through which new cells are released.

Question 19

What is the function of yellow bone marrow?

Answer 19

Yellow bone marrow is not active in hematopoiesis. It consists primarily of adipose cells.

Question 20

Where is the thymus located and what are its functions?

Answer 20

The thymus is located in the thorax, posterior to the sternum. It is fully formed at birth but undergoes involution after puberty. The thymus contains developing T cells, and its outer cortex and inner medulla are where T cells mature.

Question 21

What are the anatomy and functions of the spleen?

Answer 21

The spleen is the largest lymphatic organ and is located on the left side of the abdominal cavity. It consists of white pulp, which is lymphatic tissue, and red pulp, which contains erythrocytes, macrophages, and immune cells. The spleen functions to filter blood, react to bloodborne antigens, remove old and defective erythrocytes, and recycle iron from degraded hemoglobin.

Question 22

What is the function of lymphatic vessels?

Answer 22

Lymphatic vessels drain lymph from lymphatic capillaries.

Question 23

: Where does all lymph drain into the venous system?

Answer 23

All lymph drains into the venous system at the neck. Lymph from the right side of the head/neck and right upper limb and right thorax drains into the right subclavian vein at the right venous angle, while lymph from all other regions of the body drains into the left subclavian vein at the left venous angle.

Question 24

What is the role of the cisterna chyli?

Answer 24

The cisterna chyli is a saccular dilation located in the abdomen that receives lymph from the abdominal viscera, abdominal wall, pelvis, perineum, and lower limbs. It serves as the origin of the thoracic duct.

Question 25

Where is the thoracic duct located and where does it drain into?

Answer 25

The thoracic duct is the largest lymphatic channel. It originates from the cisterna chyli and ascends through the aortic hiatus in the diaphragm. It has a beaded appearance due to numerous valves. The thoracic duct lies in the posterior mediastinum of the thorax and drains into the left subclavian vein.

Question 26

What structures drain into the left bronchomediastinal trunk?

Answer 26

: The left bronchomediastinal trunk drains lymph from the left lung, left bronchi, left mediastinal structures, and the left thoracic wall.

Question 27

What regions are drained by the left subclavian trunk?

Answer 27

The left subclavian trunk drains lymph from the left upper limb and the superficial regions of the left thoracic wall.

Question 28

Which areas of the body are drained by the left jugular trunk?

Answer 28

The left jugular trunk drains lymph from the left side of the head and neck.

Question 29

Where does the lymph from all three trunks drain into?

Answer 29

Lymph from all three trunks (left bronchomediastinal trunk, left subclavian trunk, and left jugular trunk) drains into the left subclavian vein.

Question 30

What structures drain into the right bronchomediastinal trunk?

Answer 30

The right bronchomediastinal trunk drains lymph from the right lung, right bronchi, right mediastinal structures, and the right thoracic wall.

Question 31

What regions are drained by the right subclavian trunk?

Answer 31

The right subclavian trunk drains lymph from the right upper limb and the superficial regions of the right thoracic wall.

Question 32

Which areas of the body are drained by the right jugular trunk?

Answer 32

The right jugular trunk drains lymph from the right side of the head and neck.

Question 33

Where does the lymph from all three trunks drain into?

Answer 33

Lymph from all three trunks (right bronchomediastinal trunk, right subclavian trunk, and right jugular trunk) drains into the right subclavian vein.

Question 34

What is the function of lymph nodes?

Answer 34

Lymph nodes act as filters, trapping and phagocytosing particulate matter, as well as detecting and defending against foreign antigens.

Question 35

How does lymph flow through lymph nodes?

Answer 35

Afferent vessels carry lymph to the lymph nodes, while efferent vessels carry lymph away from the lymph nodes.

Question 36

How do lymph nodes often appear in the body?

Answer 36

Lymph nodes often aggregate into clusters and are interconnected by chains of lymph vessels.

Question 37

What are primary nodes?

Answer 37

Primary nodes are the first node or group within a lymph node chain. They are also known as outlying or peripheral nodes.

Question 38

What are terminal nodes?

Answer 38

Terminal nodes are the last node or group within a lymph node chain.

Question 39

What are sentinel nodes?

Answer 39

Sentinel nodes are hypothetical first lymph node or group of nodes draining a cancer.

Question 40

Describe the structure of a lymph node.

Answer 40

Lymph nodes are bean-shaped organs covered with a capsule. They have a hilum, which contains blood vessels and efferent lymphatic vessels. Afferent lymphatics penetrate the convex side of the lymph node and drain into subcapsular and medullary sinuses.

Question 41

Where are lymphoid follicles clearly visible?

Answer 41

Lymphoid follicles are clearly visible in the cortex of a lymph node. They contain a germinal center and are separated by trabecular sinuses.

Question 42

What types of cells are found in lymphoid follicles?

Answer 42

Lymphoid follicles contain B cells, macrophages, T cells, and plasma cells.

Question 43

How are lymph nodes arranged?

Answer 43

Lymph nodes are arranged in chains within the body.

Question 44

How are lymph vessels and nodes grouped?

Answer 44

Lymph vessels and nodes are grouped into deep and superficial regions.

Question 45

Where are superficial inguinal nodes located?

Answer 45

Superficial inguinal nodes are located in the subcutaneous tissue and are more numerous than veins in that area.

Question 46

How do superficial lymphatic vessels drain?

Answer 46

Superficial lymphatic vessels converge towards and follow venous drainage, eventually draining into deep lymphatic vessels.

Question 47

Where are superficial lymph nodes located?

Answer 47

Superficial lymph nodes are located superficial to the deep fascia and are associated with superficial veins. They drain to deep nodes.

Question 48

How do deep lymphatic vessels accompany arteries?

Answer 48

Deep lymphatic vessels run alongside arteries and receive drainage from internal organs.

Question 49

Where are deep lymph nodes located?

Answer 49

Deep lymph nodes are closely located to vasculature and viscera, and their nomenclature is taken from neighboring structures.

Question 50

What is Mucosal Associated Lymphatic Tissue (MALT)?

Answer 50

Mucosal associated lymphatic tissue, such as palatine tonsils, is a specialized lymphatic tissue that guards against pathogenic substances and serves as a site for the initial immune response.

Question 51

What happens in lymphatic nodules?

Answer 51

Lymphatic nodules are characterized by clonal proliferation of B cells and subsequent development of lymphatic nodules, which are dense oval masses of lymphocytes and macrophages that congregate in response to pathogens or can be a permanent feature.

Question 52

Where can diffuse lymphatic tissue be found in the body?

Answer 52

Diffuse lymphatic tissue can be found in the lamina propria (LP) of the large intestine.

Question 53

Where are lymphatic nodules found?

Answer 53

Lymphatic nodules are found in the palatine tonsil and multiple nodules are present in the ileum, forming Peyer’s patches.

Question 54

What is lymphedema and what can cause it?

Answer 54

Lymphedema is the swelling of limbs due to blockage or damage to the lymphatic system. It can be caused by trauma, surgical injury, surgical removal (such as in cancer treatment), infection, or radiation therapy.

Question 55

What is lymphadenopathy and what are its causes?

Answer 55

Lymphadenopathy refers to the swelling of lymph nodes. It can be caused by various factors such as bacterial, viral, fungal, or filarial (threadworm) infections, skin wounds (e.g., cat scratch caused by Bartonella henselae), metastases (spread of cancer), primary malignancies (lymphoma), lymphadenitis (infection of lymph nodes), or lymphangitis (infection of lymph vessels). Ascending lymphangitis requires urgent medical treatment.

Question 56

What is the role of lymphatic nodes in disease?

Answer 56

Lymphatic nodes can be involved in disease processes such as metastases, where cancer cells spread from elsewhere in the body through the lymphatics. Carcinomas are the most common type of cancer that spreads through the lymphatic system. Lymphoma, which is cancer of lymphocytes, can also affect lymphatic nodes, including Hodgkin lymphoma and non-Hodgkin lymphoma.