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Levels of Lymph Nodes
The document discusses the lymphatic system's functions, including fluid recovery, immunity, and lipid absorption, along with its anatomical components such as lymph, lymphatic vessels, and lymphatic organs. It explains the mechanisms of lymph flow, focusing on how lymphatic vessels operate without a central pump and the role of muscles and respiratory actions in aiding circulation. Additionally, it details the classification and locations of various lymph nodes in the body, highlighting their significance in immune defense and fluid transport.
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Levels of Lymph Nodes
- 1. LEVELS OF LYMPH NODES DR AMITHAG , BDS, MDS ORAL AND MAXILLOFACIAL PATHOLOGY
- 2. FUNCTIONS OF LYMPHATICSYSTEM • The lymphatic system has three functions: • Fluid recovery. • Immunity • Lipid absorption • The lymphatic vessels of the small intestine receive the special designation of lacteals or chyliferous vessels.
- 3. THE MAIN FUNCTIONSOF THE LYMPHATIC SYSTEM ARE AS FOLLOWS • To collect and transport tissue fluids from the intercellular spaces in all the tissues of the body, back to the veins in the blood system; • It plays an important role in returning plasma proteins to the bloodstream; • Digested fats are absorbed and then transported from the villi in the small intestine to the bloodstream via the lacteals and lymph vessels. • New lymphocytes are manufactured in the lymph nodes;
- 4. • Antibodies andlymphocytes assist the body to build up an effective immunity to infectious diseases; • Lymph nodes play an important role in the defence mechanism of the body. They filter out micro-organisms (such as bacteria) and foreign substances such as toxins, etc. • It transports large molecular compounds (such as enzymes and hormones) from their manufactured sites to the bloodstream.
- 5. COMPONENTS OF LYMPHATICSYSTEM The components of the lymphatic system are :- • lymph, the recovered fluid; • Lymphatic vessels, which transport the lymph; • Lymphatic tissue, composed of aggregates of lymphocytes and macrophages that populate many organs of the body; and • Lymphatic organs, in which these cells are especially concentrated and which are set off from surrounding organs by connective tissue capsules.
- 6. LYMPH • Lymph isusually a clear, colorless fluid, similar to blood plasma but low in protein. Its composition varies substantially from place to place. • Origin of Lymph :- • Lymph originates in microscopic vessels called lymphatic capillaries. These vessels penetrate nearly every tissue of the body but are absent from the central nervous system, cartilage, bone, and bone marrow. • The gaps between lymphatic endothelial cells are so large that bacteria and other cells can enter along with the fluid.
- 7. LYMPH Origin of Lymph:- • The overlapping edges of the endothelial cells act as valve like flaps that can open and close. • When tissue fluid pressure is high, it pushes the flaps inward (open) and fluid flows into the lymphatic capillary. When pressure is higher in the lymphatic capillary than in the tissue fluid, the flaps are pressed outward (closed).
- 8. Lymphatic Capillaries. (a)Relationship of the lymphatic capillaries to a bed of blood capillaries. (b) Uptake of tissue fluid by a lymphatic capillary.
- 9. Lymphatic Vessels :- •They have a tunica interna with an endothelium and valve, a tunica media with elastic fibers and smooth muscle, and a thin outer tunica externa. • Their walls are thinner and their valves are more numerous than those of the veins.
- 10. MECHANISM OF LYMPHATICFLOW • Lymph flows under forces similar to those that govern venous return, except that the lymphatic system has no pump like the heart. • Lymph flows at even lower pressure and speed than venous blood; it is moved primarily by rhythmic contractions of the lymphatic vessels themselves, which contract when stretched by lymph. • The lymphatic vessels, like the veins, are also aided by a skeletal muscle pump that squeezes them and moves the lymph along. • Also like the medium veins, lymphatic vessels have valves that prevent lymph from flowing backward.
- 11. • Since lymphaticvessels are often wrapped with an artery in a common sheath, arterial pulsation may also rhythmically squeeze the lymphatic vessels and contribute to lymph flow. • A thoracic (respiratory) pump aids the flow of lymph from the abdominal to the thoracic cavity as one inhales, just as it does in venous return. • Finally, at the point where the collecting ducts join the subclavian veins, the rapidly flowing bloodstream draws the lymph into it. • Considering these mechanisms of lymph flow, it should be apparent that physical exercise significantly increases the rate of lymphatic return.
- 12. LYMPHATIC CELLS ANDTISSUES • T lymphocytes (T cells). These are so-named because they develop for a time in the thymus and later depend on thymic hormones. There are several subclasses of T cells. • B lymphocytes (B cells). These are named after an organ in birds (the bursa of Fabricius) in which they were first discovered. When activated, B cells differentiate into plasma cells, which produce circulating antibodies, the protective gamma globulins of the body fluids.
- 13. LYMPHATIC ORGANS • PrimaryLymphatic Organs :- • Lymphatic (lymphoid) organs contain large numbers of lymphocytes, a type of white blood cell that plays a pivotal role in immunity. • The primary lymphatic organs are • the red bone marrow and • the thymus gland. • Lymphocytes originate and/or mature in these organs.
- 14. PRIMARY LYMPHATIC ORGANS •Red Bone Marrow • It is the site of stem cells that are ever capable of dividing and producing blood cells. • Some of these cells become the various types of white blood cells: neutrophils, eosinophils, basophils, lymphocytes, and monocytes. • In a child, most of the bones have red bone marrow, but in an adult it is limited to the sternum, vertebrae, ribs, part of the pelvic girdle, and the proximal heads of the humerus and femur.
- 15. RED BONE MARROW •Red bone marrow is the site of stem cells that are ever capable of dividing and producing blood cells. Some of these cells become the various types of white blood cells: • neutrophils, eosinophils, basophils, lymphocytes, and monocytes . • In a child, most bones have red bone marrow, but in an adult it is limited to the sternum, vertebrae, ribs, part of the pelvic girdle, and the proximal heads of the humerus and femur.
- 16. RED BONE MARROW •The red bone marrow consists of a network of reticular tissue fibers, which support the stem cells and their progeny. • They are packed around thin-walled sinuses filled with venous blood. Differentiated blood cells enter the bloodstream at these sinuses. • Lymphocytes differentiate into the B lymphocytes and the T lymphocytes. • Bone marrow is not only the source of B lymphocytes, but also the place where B lymphocytes mature. • T lymphocytes mature in the thymus.
- 18. CLASSIFICATION Node Location AfferentEfferent Superficial Lymph Nodes of the Head Occipital (2-4) Superior nuchal line between sternocleidomastoid and trapezius Occipital part of scalp Superficial cervical lymph nodes Accessary lymph Mastoid (1-3) Superficial to sternocleidomastoid insertion Posterior parietal scalp Skin of ear, posterior external acoustic meatus Superior deep cervical nodes Accessary nodes Preauricular (2-3) Anterior to ear over parotid fascia Drains areas supplied by superficial temporal artery Anterior parietal scalp Anterior surface of ear Superior deep cervical lymph nodes
- 20. Parotid (up to10 or more) About parotid gland and under parotid fascia Deep to parotid gland External acoustic meatus Skin of frontal and temporal regions Eyelids, tympanic cavity Cheek, nose (posterior palate) Superior deep cervical lymph nodes Facial Superficial(up to 12) Maxillary Buccal Mandibular Distributed along course of facial artery and vein Skin and mucous membranes of eyelids, nose, cheek Submandibular nodes Deep Distributed along course of maxillary artery lateral to lateral pterygoid muscle Temporal and infratemporal fossa Nasal pharynx Superior deep cervical lymph nodes
- 21. Cervical Lymph Nodes SuperficialAnterior jugular vein between superficial cervical fascia and infrahyoid fascia Skin, muscles, and viscera of infrahyoid region of neck Superior deep cervical lymph nodes Deep Between viscera of neck and investing layer of deep cervical fascia Adjoining parts of larynx, thyroid gland Superior deep cervical lymph nodes Anterior cervical/Superficial Submental (2-3) Submental triangle Chin Medial part of lower lip Lower incisor teeth and gingiva Tip of tongue Cheeks Submandibular lymph node to jugulo-omohyoid lymph node and superior deep cervical lymph nodes
- 23. Submandibula r (3-6) Submandibular triangle adjacent to gland Facialnodes Chin Lateral upper and lips Submental nodes Cheeks and nose, anterior nasal cavity Maxillary and mandibular teeth and gingiva Oral palate Lateral parts of 2/3 of tongue Superior deep cervical lymph nodes and jugulo-omohyoid lymph nodes Superficial cervical (1-2) Along external jugular vein superficial to sternocleidomast oid muscle Lower part of ear and parotid region Superior deep cervical lymph nodes
- 26. Deep Cervical LymphNodes Superior deep cervical Surrounding internal jugular vein deep to sternocleidomastoi d and superior to omohyoid muscle Occipital nodes Mastoid nodes Preauricular nodes Parotid nodes Submandibular nodes Superficial cervical nodes Retropharyngeal nodes Inferior deep cervical nodes or separate channel to jugulo- subclavian junction Jugulodigastric Junction of internal jugular vein and posterior digastric muscle Palatine and lingual tonsils Posterior palate Lateral portions of the anterior 2/3 of tongue Inferior deep cervical lymph nodes
- 28. Jugulo- omohyoid Above junction of internaljugular vein and muscle Posterior 1/3 of tongue Submandibular nodes Submental nodes Inferior deep cervical lymph nodes Inferior deep cervical Along internal jugular vein below omohyoid muscle deep to the sternocleidomastoi d muscle Transverse cervical nodes Anterior cervical nodes Superior deep cervical nodes Jugular trunk Retropharynge al (1-3) Retropharyngeal space Posterior nasal cavity Paranasal sinuses Hard and soft palate Nasopharynx, oropharynx Anditory tube Superior deep cervical nodes
- 30. Accessory (2-6) Alongaccessory nerve in posterior triangle Occipital nodes Mastoid nodes Lateral neck and shoulder Transverse cervical nodes Transverse cervical (1-10) Along transverse cervical blood vessels at level of clavicle Accessory nodes Apical axillary nodes Lateral neck Anterior thoracic wall Jugular trunk or directly into thoracic duct or right lymphatic duct or independently junction of jugular vein and subclavian vein
- 31.
Editor's Notes
- #3 1. Fluid recovery Each day, they lose an excess of 2 to 4 L of water and one-quarter to one-half of the plasma protein. The lymphatic system absorbs this excess fluid and returns it to the bloodstream by way of the lymphatic vessels. 2. Immunity. As the lymphatic system recovers excess tissue fluid, it also picks up foreign cells and chemicals from the tissues. On its way back to the bloodstream, the fluid passes through lymph nodes, where immune cells stand guard against foreign matter. When they detect it, they activate a protective immune response. 3. Lipid absorption. In the small intestine, special lymphatic vessels called lacteals absorb dietary lipids that are not absorbed by the blood capillaries
- #7 A lymphatic capillary consists of a sac of thin endothelial cells that loosely overlap each other like the shingles of a roof. The cells are tethered to surrounding tissue by protein filaments that prevent the sac from collapsing. Unlike the endothelial cells of blood capillaries, lymphatic endothelial cells are not joined by tight junctions. The gaps between them are so large that bacteria and other cells can enter along with the fluid.
- #10 Lymphatic vessels form in the embryo by budding from the veins, so it is not surprising that the larger ones have a similar histology.
- #13 The T stands for thymus-dependent.