1. the lymphatic system consists of The lymph conducting channels
Lymphoid tissues
Lymphoid organs

2. The lymphatic system is part of the immune system and acts as a secondary (accessory) circulatory system.

3. Functions of the lymphatic system:
remove excess fluids from body tissues,
absorb fatty acid and transport fat to circulatory system, and
produce immune cells (lymphocytes, monocytes, and plasma cells).

4. Blood fluid escapes through the thin-walled capillaries into spaces between body tissue cells.
Lymph vessels, which have very thin walls, pick up these fluids called lymph.

5. Composition
Lymphatic vessel
Lymphatic capillary
Lymphatic vessels: two sets, superficial and deep
Lymphatic trunks: nine
Lymphatic ducts: thoracic duct, right lymphatic duct
Lymphatic organ
Lymphatic nodes
Tonsil, spleen, thymus
Lymphatic tissue
Include diffused lymphoid tissues and lymph nodules. They are mainly situated in the wall of the respiratory-alimentary tracts and consist of aggregated of lymphocytes and associates cells.

6. Tissue fluid and its formation
composition same as blood but without read blood cells (RBCs), platelets & proteins
because they are too large to leak out of the capillaries
- forms a link between blood and cells, providing a medium for exchange of materials between blood & cells

7. At the arterial end of a capillary, liquid is forced out as tissue fluid which is similar to plasma in composition except its has no plasma proteins, platelets & RBCs.
 At the venous end, some fluid returns to blood while some enters lymph vessels which eventually join to a vein near the heart and thus returns to blood finally.

8. Lymph
some tissue fluid returns to capillaries by osmosis while
some (about 10%) goes into lymph capillaries;
this fluid is now called lymph
Path:
Blood  lymph capillaries
 lymph vessels
 lymph ducts
 Blood
- Lymph re-enters blood

9. Lymphatic capillary Begin blindly
The wall is composed of a single layer of overlapping endothelial cells
They are numerous and form complex networks
The brain, spinal cord, bone marrow, parenchyma of spleen and eyeball lack lymphatic capillaries

10. Lymph is driven by contraction of surrounding muscles, aided by valves which enable one-way flow to the neck.

11. Movement of lymph through the lymphatic system:
1. Hydrostatic pressure
2. Muscle contraction
3. Inspiratory movement
4.Valves to ensure one-way traffic towards the heart

12. The Lymphatic System Heart Vein Lymphatic duct Artery Lymphatic trunk
Capillaries
Lymphatic node
Cell
Tissue fluid
Lymphatic capillary
Lymphatic vessel

13. lymphatic vessels lymphatic capillary lymphatic vessel
lymphatic trunks
lumbar trunks(2)
brochomediastinal trunks(2)
subclavian trunks(2)
jugular trunks(2)
intestinal trunk
lymphatic ducts
thoracic duct
right lymphatic duct

14. Lymphatic vessel Features of structure
Three layered wall similar to, but thinner than vein,
More numerous valves than in vein
Interposed by lymph node at interval along the course
Arranged in superficial and deep sets

15. Lymphatic trunks
right and left jugular trunks
right and left subclavian trunks
right and left bronchomediastinal trunks
right and left lumbar trunks
intestinal trunk

16. Lymphatic ducts Right lymphatic duct
Formed by union of right jugular, subclavian, and bronchomediastinal trunks
Ends by entering the right venous angle
Receives lymph from right half of head, neck, thorax and right upper limb

17. Thoracic duct
Begins in front of L1 as a dilated sac, the cisterna chyli , which formed by joining of left and right lumbar trunks and intestinal trunk
Enter thoracic cavity by passing through the aortic hiatus of the diaphragm and ascends along on the front of the vertebral column, between thoracic aorta and azygos vein

18. Thoracic duct
Travels upward, veering to the left at the level of T5
At the roof of the neck, it turns laterally and arches forwards and descends to enter the left venous angle
Just before termination, it
receives the left jugular,
subclavian and bronchomediastinal
trunks

19. Thoracic duct
Drains lymph from lower limbs, pelvic cavity, abdominal cavity, left side of thorax, and left side of the head, neck and left upper limb

20. Lymphatic vessel Have valves that give them a beaded appearance
Two sets: superficial (lie in the superficial fascia ) and deep (run with blood vessels and nerves)
Passes through at least one lymph node and often several

21. lymphatic ducts thoracic duct from cisterna chyli (L1)
to left venous angles
left jugular trunk
left subclavian trunk
left bronchomediastinal trunk
right and left lumbar trunk
intestinal trunk
right lymphatic duct
right brochomediastinal trunk
right subclavian trunk
right jugular trunk

22. The lymph vessels join to form larger ducts that pass through lymph nodes (or glands).
Each lymph node has a fibrous outer covering (capsule), a cortex, and a medulla.

23. (Small oval or bean-shaped bodes
lymph node
(Small oval or bean-shaped bodes
Afferent vessels enter the node on its convex surface, and efferent vessels leave the node at its concave surface－the hilum
Arranged in groups, along the blood vessels
Regional nodes
is the lymph node where the lymph of the organ or part of the body drainage to firstly

24. Photo from U. S. Federal Government courtesy of Wikipedia.

25. Lymph nodes filter foreign substances, such as bacteria and cancer cells, from the lymph before it is re-entered into the blood system through the larger veins.
Lymph nodes, which are scattered among the lymph vessels, act as the body’s first defense against infection.

26. Lymph nodes produce the following cells:
Lymphocytes – a type of white blood cell,
Monocytes – a leukocyte that protects against blood-borne pathogens, and
Plasma cells – produce antibodies.

27. Each lymph node has its own blood supply and venous drainage.
The lymph nodes usually have names that are related to their location in the body.

28. When a specific location gets infected, the lymph nodes in that area will enlarge to fight the infection.
If the lymph node closest to an infected area is unable to eliminate the infection, other lymph nodes in the system will attempt to fight the infection.

29. This is particularly critical in the case of cancer, which can be spread from its point of origin to all parts of the body through the lymphatic system.

30. Lymph drainage of the body

31. The lymphatic drainage of head
Lymph nodes of head
Located at junction of head and neck
Consist of
Occipital lymph nodes
Mastoid lymph nodes
Parotid lymph nodes
★ Submandibular lymph nodes lies near the submandibular gland, receive lymphatic vessels from the face, nose and mouth
submental lymph nodes
Drain into deep cervical lymph nodes

32. Lymph nodes of the neck Anterior cervical ln.
Superficial anterior cervical lymph nodes
Deep anterior cervical lymph nodes
Lateral cervical ln. ★ Superficial lateral cervical ln. －lie along the external jugular vein
★ Deep lateral cervical ln. －extend along the internal jugular vein

33. Lymph nodes of the neck ★ Deep lateral cervical ln.
Extend along the internal jugular vein from the base of skull to the root of neck
Divided into superior deep lateral cervical ln. and inferior deep lateral cervical ln.
Receive lymphatic vessels from head, neck, tongue, larynx, cervical parts of esophagus and trachea, thyroid gland, upper parts of the thoracic wall and breast
Efferent vessels form the jugular trunk
Left jugular trunk joins the thoracic duct
Right jugular trunk joins the right lymphatic duct

34. Lymph nodes of the neck
Superior deep lateral cervical ln. Jugulodigastric ln.
Lies at the junction of posterior belly of digastric and internal jugular vein
Drain the nasopharynx, palatine tonsil and root of tongue
Inferior deep lateral cervical ln. Juguloomohyoid ln.
Lies at the junction of the intermediate tendon of omohyoid and internal jugular vein
Drain the apex of tongue

35. Lymph nodes of the neck Inferior deep lateral cervical ln.
Supraclavicular lymph nodes
Lie along transverse cervical a. & v.
palpable in the supraclavicular fossa. The most notable supraclavicular lymph node is Virchow's node. which can contain metastasis of visceral (abdominal) tumor.
Retropharyngeal ln.
Lying vertically behind the pharynx
drain nasopharyngeal lymph

36. Lymph nodes of upper limb
Cubital lymph node
lies above medial epicondyle of humerus
Receive lymph vessels from forearm
Axillary lymph node
arranged in five groups

37. Axillary lymph nodes
Axillary lymph nodes vary in size from a pin-head to a large bean.
They are arranged in five groups.

38. Axillary lymph nodes
Pectoral lymph nodes Lying along the lower border of pectoralis minor behind the pectoralis major
Receive lymph vessels from the lateral quadrants of the breast and superficial vessels from the anterolateral abdominal wall above the level of the umbilicus

39. Axillary lymph nodes
Lateral lymph nodes Along medial side distal part of axillary vein
Receives lymph from upper limb

40. Axillary lymph nodes Subscapular lymph node
Lying along subscapular vessels, in front of the subscapularis
Receive superficial lymph vessels from the back, down as far as the level of the iliac crests
Efferents of above three groups pass to central lymph node

41. Axillary lymph nodes Central lymph node
Lying in the center of the axilla in the axillary fat
Receive lymph from the above three nodes
Efferents pass to apical lymph node

42. Axillary lymph nodes
Apical lymph node
infraclavicular lymph nodes
Lying at the apex of the axilla at the lateral border of the fist rib
Receive lymph of the efferent lymph vessels from all the other axillary nodes
The efferents of the apical nodes form the subclavian trunk

43. Axillary lymph nodes
Efferents form subclavian trunk, the right subclavian trunk joins the right lymphatic duct; left usually drains directly into thoracic duct
Apical ln.
Subclavian trunk
Central ln.
Pectoral ln.
Lateral ln.
Subscapular ln.

44. Lymphatic drainage of thorax
The lymphatic drainage of thoracic wall
To axillary lymph nodes
To parasternal lymph nodes (along internal thoracic vessels)
To intercostals lymph nodes from deeper structures

45. The lymphatic and venous drainages of the breast are of great importance in the spread of carcinoma.
About three quarters of the lymphatic drainage is to the axillary nodes: (1) Lymphatics pass around the edge of the pectoralis major and reach the pectoral group of axillary nodes;
(2) routes through or between the pectoral muscles may lead directly to the apical nodes of the axilla;
(3) lymphatics follow the blood vessels through the pectoralis major and enter the parasternal (internal thoracic) nodes;
(4) connections may lead across the median plane and hence to the contralateral breast;
(5) lymphatics may reach the sheath of the rectus abdominis and the subperitoneal and subhepatic plexuses.
It should be noted that free communication exists between nodes below and above the clavicle and between the axillary and cervical nodes.

46. lymph nodes of the thorax
Pulmonary ln. lie in the angles of bifurcation of branching lobar bronchi
Bronchopulmonary hilar ln. －lie in the hilums of the lung
Tracheobronchial ln. －situated above or below the bifurcation of trachea
Paratracheal ln. －along each side of the trachea

47. lymph nodes of the thorax
Anterior mediastinal lymph node
Lies anterior to the large blood vessels of thoracic cavity and pericardium
The efferents unite with those of paratracheal lymph nodes and parasternal lymph nodes to form the right and left bronchomediastinal trunks
The left bronchomediastinal trunk terminates in thoracic duct, and right in the right lymphtic duct
Posterior mediastinal lymph nodes lie along the esophagus and thoracic aorta

48. Lymph nodes of lower limb
Popliteal ln.
Embedded in the fatty connective tissue of popliteal fossa
Receive superficial lymphatic vessels from posterolateral part of calf, and from deep lymphatic vessels accompanying anterior and posterior tibia a.
Efferents pass to the deep inguinal ln.

49. Lymph nodes of lower limb
Superficial inguinal lymph nodes Superior group:
Lies just distal to the inguinal ligament
Receive lymph vessels from anterior abdominal wall below umbilicus, gluteal region, perineal region, external genital organs
Inferior group:
Lies vertical along the terminal great saphenous v.
Receives all superficial lymph vessels of lower limb, except for those from the posterolateral part of calf
Efferent vessels drain into the deep inguinal ln. or external iliac ln.

50. Lymph nodes of lower limb
Deep inguinal lymph nodes
Lie medial to the femoral v.
Receive deep lymph vessels of lower limb, perineal region, and efferent vessels from the superficial inguinal ln.
Drain into the external iliac ln.

51. Lymph nodes of pelvis Internal iliac lymph node
Surround internal iliac vessels
Receive afferents from pelvic viscera, perineum, buttock and back of thigh
External iliac lymph nodes
Lie along external iliac artery
Receive afferents from lower limb and some parts of pelvic viscera
Sacral lymph node
locate along middle sacral a. and lateral sacral a.
Receive lymph from posterior pelvic wall ,rectum,prostate or uterus
Common iliac lymph node
Lie along common iliac artery
Receive afferents from all the above nodes
Efferent pass to lumbar lymph node

52. Lymph nodes of abdomen Lymphatic drainage of abdominal wall
To axillary lymph node from region above umbilicus
To superficial inguinal lymph node from region below umbilicus
To lumbar lymph node from post wall of abdomen

53. Lymph nodes of abdomen Lymphatic drainage of abdominal viscera
Lumbar lymph nodes
Lie on posterior abdominal wall, along the abdominal aorta and inferior vena cava
Receive lymph from kidneys, suprarenal glands, testes, ovaries, fundus of uterus, uterine tubes, and common iliac nodes
Right and left lumbar trunks formed by efferent vessel
Paired viscera－drain to the lumbar lymph nodes

54. Lymph nodes of abdomen
Right and left gastric ln. lie along the same vessels and finally to the celiac ln.
Right and left gastroomental ln. lie along the same vessels, the former drain into subpyloric ln., the latter drain into splenic ln.
Suprapyloric and subpyloric ln. receive lymphatics from pyloric part and finally to the celiac ln.
Splenic ln. receive lymphatics from fundus and left third of stomach, and finally to the celiac ln.
Celiac lymph nodes －situated around the celiac trunk

55. Lymph nodes of abdomen
Superior mesenteric lymph node －situated around superior mesenteric a.
Inferior mesenteric lymph node －situated around inferior mesenteric a.
Intestinal trunk －formed by efferent vessel of celiac, superior and inferior lymph nodes

56. Thymus Featrues Consists of two elongated lobes
Is large organ in the fetus
Occupies the thoracic cavity behind the sternum
Secrete lymphopoietin

57. Thymus
The thymus is partly in the neck and partly in the thorax. It comprises one to three lobes, each of which consists of numerous lobules containing lymphocytes, which are important in the development and maintenance of the immune system. The cervical part of the thymus lies on the anterior and lateral sides of the trachea, whereas the thoracic part lies posterior to the superior portion of the sternum. The organ has a profuse blood supply and lymphatic drainage. The thymus reaches its greatest size at puberty and then begins to regress. Much of its substance is replaced by fat and fibrous tissue, but thymic tissue never disappears completely. Function:to develop lymph cell

58. Spleen Shape Location:
The largest single mass of lymphoid tissue in the body
Reddish in color
Location:
lies in the left hypochondriac region (between stomach and diaphragm) deep to the 9th to 11th rib
its long axis corresponds roughly to the 10th rib
Its lower pole extends forward only as far as the midline and cannot be palpated on clinical examination

59. Spleen Two surfaces Two extremities Two border
Diaphragmatic: smooth, convex
Visceral: concave, hilum of spleen
Two extremities
Anterior－wider
Posterior－rounder
Two border
Superior－has 2-3 splenic notch, which serve as a landmark on palpation when it is enlarge; normally it is not palpable
Inferior－rounder

60. Spleen Function Erythrocyte storage Phagocytosis Cytopoiesis
Immune responses