Lymphatic System Anatomy PDF

Anatomy of lymphatic system Dr /Bothina Zakaria Lecturer of human anatomy  Lymphatic system It is part of immune system. it keeps body fluids levels in balance and defends the body against infections. It is formed of: ✓Lymph vessels. ✓lymph nodes. ✓ly...

Anatomy of lymphatic system Dr /Bothina Zakaria Lecturer of human anatomy  Lymphatic system It is part of immune system. it keeps body fluids levels in balance and defends the body against infections. It is formed of: ✓Lymph vessels. ✓lymph nodes. ✓lymphoid organs. ✓Lymphoid tonsils. Lymph: it is colorless fluid which circulates runs inside the lymphatic vessels, which accompany the veins but not seen by naked eyes. ✓ In small intestine, fats are absorbed by intestinal epithelium and packed to form milky opaque lymph which is called chylomicrons; here the lymph is termed chyle. ✓ It begins as lymphatic capillaries. Lymphatic capillaries It present in the most areas in the body except brain, bone marrow, epidermis, eyeball and cartilage  Lymphatic vessels (Lymphatics) Movement of lymph is controlled by the action of adjacent muscle especially the skeletal muscles and pulse of arteries. Unidirectional flow maintained by the presence of valves in the lymphatics.  Lymph nodes These are several small masses of lymphoid tissue present at the pathway of lymphatic vessels, small and encapsulated (0.1 to 2.5 cm long). It works as filters for foreign substances and contains elements of body defense systems like lymphocytes and macrophages. It presents in certain groups which may be superficial to skin at areas and deep in other areas. 1.Cervical lymph nodes which drain head and neck. 2.Axillary lymph nodes which drain upper limb and breast. 3.Mediastinal lymph nodes which drain thoracic organs. 4.Aortic lymph nodes which drain abdominal organs. 5.Inguinal lymph nodes which drain groin and lower limbs. Lymphatic trunks and ducts  Lymph from the right side of head and neck, right upper limb, right side of the thorax and right upper abdominal wall is drained to right lymphatic duct. Lymph from the left side of the body is drained to the thoracic duct.  Thoracic duct ▪ It is the largest lymphatic duct in the body ▪ It drains lymph from the lower limbs, pelvis, perineum, abdomen, left side of the neck and left upper limb. ▪ Length = 45 cm.  Course: it takes origin from the upper end of the abdominal lymph trunks or cisterna chyli in front of the lower border of the last thoracic vertebra. It reaches the thorax by ascending through the aortic opening of the diaphragm. It ascends in front the vertebral column.  It crosses gradually from right to left side of the median plane of the body in front T5. At level of C7, its terminate in the angle of junction between left internal jugular and left subclavian vein.  Lymphoid organs Parts of body that produce lymphocytes such as: ✓ Thymus gland. ✓ Tonsils. ✓ Spleen. ✓ Red bone marrow. ✓ Lymphoid follicles at wall of alimentary tract. Tonsils Adenoid Thymus ▪ It is a central lymphoid organ which involved in early development of the immune system, it is well developed at birth and grows until puberty, and later on it is diminished at size and replaced by fibrous and adipose tissue. ▪ It has unequal 2 pyramidal lobes which are bound together by loose connective tissue. Spleen  It is considered as the largest lymphoid organ in the body, it is reddish brown in color. Shape: pyramidal in shape The spleen has two ends, three borders and two surfaces  The anterior end is expanded and directed downwards and forwards, and reaches the mid- axillary line. The posterior end is rounded. It is directed upwards, backwards and medially, and rests on the upper pole of the left kidney.  The superior border is characteristically notched near the anterior end. The inferior border is rounded. The intermediate border is also rounded and is directed to the right. ✓ Diaphragmatic(LATERAL) surface is convex and smooth contains impressions from the 9th to 11th ribs. ✓ The visceral(MEDIAL) surface has three impressions ,these are for the stomach, for the splenic flexure of the colon and the renal area for the left kidney.  The hilum lies on the visceral surface. It transmits the splenic vessels and nerves, and provides attachment to the ligaments.