Anatomy of Lymphatic system

ANATOMY OF LYMPHATIC SYSTEM

1. ANATOMY AND PHYSIOLOGY OF LYMPHATIC SYSTEM BY:DIPALI HARKHANI

2. WHAT IS LYMPHATIC SYSTEM? The  lymphatic system  is part of the   circulatory system  and an important part of the  immune system , comprising a network of  lymphatic vessels  that carry a clear fluid called   lymph  (from Latin,  lympha  meaning " water”)directionally towards the heart. 

3. COMPOSITION OF LYMPH T he composition of lymph is similar to that of plasma but the constituents have some additional substances that are too large to pass through blood capillary walls E x. macroparticles from damaged area Dameged cells by disease and bacteria.

4. LYMPH VESSELS T hese originate as blind end tubes in the interstitial spaces. S tructurely,they are same as blood capillaries. T heir walls are more permeable to all interstitial fluid including proteins and cell debris. T he capillaries joint to form larger lypmph vessels. L ymph vessels have numerous cup shaped valves that prevent back flow of movements of lymph in vessels. L ymph vessels join together to form two larger ducts ( i ) The T horacic duct (ii) The right L ymphatic duct

5. LYMPH VESSELS

6. ( i ) THE THORACIC DUCT What is duct?  A  duct  is a circumscribed channel leading from an   organ . Length- 40cm Ascends through the diaphragm and passes upwards in the thoracic cavity. it drains Lymph from B oth legs T he pelvicabdominal cavities L eft half of the T he Thorax H ead & Neck T he Left upper Limbs.

7. (ii) THE RIGHT LYMPHATIC DUCT IT LIES IN THE ROOT OF THE NECK AND OPEN INTO RIGHT SUBCLAVIAN VEIN. IT DRAINS LYMPH FROM RIGHT HALF OF THE THORAX NECK RIGHT UPPER LIMB

8. LYMPH NODES A ll the small and medium size lymph vessels open into lymph nodes. The size of a node arise from pin head to the largest is about the size of an almond S tructure H as a fibrous capsule,dips down into the node forming trabecula that divide the node into compartments. B elow the capsule is sub capsular substance. T he outer portion is called cortex . T he inner portion is called medulla .

9. LYMPH NODES I t has tightly packed. lymphocytes,macrophages and plasma cells. F unctions P hagocytic action. P roduction of antibodies. E nlargement of lymph nodes,when the area of drainage is infected. A ctivate T and B lymphocytes. F iltration of lymph.

10. LYMPHATIC TISSUE OR LYMPHATIC ORGANS T he lymphatic organs are found in a number of situations n the body. such as ( i )Tonsils (ii)Spleen (iii)Bone M arrow (iv)Thymus G land ( i ) Lonsils Lingual Tonsils are the paired and lie at the base of the tongue.

11. LINGUAL TONSILS

12. (ii)SPLEEN T he S pleen is formed partly by lymphatic system. L ocation -left hypochondriac region L ength- 12 cm W idth- 7 cm T hick- 2.5 cm S hape -oval R elations - Posteriorly & Superiorly- Diaphragm I nferiorly -Left colic flexure of large intestine A nteriorly -Fundus of the stomach

13. STRUCTURE OF SPLEEN E nclosed in peritoneum. C overed by a capsule. T he trabaculae subdivides the structure into lobules. T he spleen don’t has no afferent lymphatic vessels. So it does not filter lymph. S pleen consists red and white pulp. B lood supply S plenic artery S plenic vein L ymphatic vessels N erves

14. FUNCTIONS OF SPLEEN P hagocytosis of Bacteria B reak down of RBC. P roduction of Antibodies.

15. (iii)BONE MARROW T he R ed B one M arrow is a key element of the  lymphatic system , Being one of the primary lymphoid organs that generate  lymphocytes  from immature hematopoietic  progenitor cells . T he bone marrow and  Thymus  constitute the primary lymphoid tissues involved in the production and early selection of lymphocytes. F urthermore, bone marrow performs a  valve -like function to prevent the backflow of  lymphatic fluid  in the lymphatic system .

16. (iv) THYMUS GLAND W eight -15 gms R elations - A nteriorly -Sternum. P osteriorly –Aortic arch. Superiorly- R oot of neck. Inferiorly -Heart. Laterally- L ungs. L obes - two E ach lobule has aggregation of lymphocytes. T he cortex is composed of aggregation of lymphocytes. M edulla contains less lymphocytes. T he T hymus gland develops mature T lymphocytes .

17. BLOOD SUPPLY TO THE THYMUS GLAND I nferior thyroid artery. I nternal thoracic artery. N erves derived from vagus nerve. F unctions A ctivation of T-lymphocytes P roduction of antibodies. P roduction of T hymosin hormone. [ T hymosins  are small proteins present in many animal tissues. they are named thymosins because they were originally isolated from the  thymus ]