Lymphatic system

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SYSTEM LYMPHATIC

Lymphatic systemThe lymphatic system is a complex network of lymphoid organs, lymph nodes, lymphatic ducts, lymphatic tissues, lymphatic capillaries, and lymphatic vessels that produce and transport lymphatic fluid (lymph) from the tissues to the circulatory system. vein-like vessels (lymphatic vessels), which are distributed throughout the body and collect tissue fluid that has not returned to the blood capillaries, filtering it and returning it to the bloodstream. The lymphatic system is also an important component of the immune system as it collaborates with white blood cells to protect against invading bacteria and viruses. The study of the lymphatic system in the dissecting room is not very satisfactory because the tenuousness of the vessel walls and their small size make them indistinguishable from neighboring tissues.

Most of the information about the lymphatic system has been obtained from laboratory studies with injection of stained mass into very small vessels. Injection into large vessels does not present satisfactory results for study of the lymphatic system due to the presence of numerous valves.

It has three Interrelated Functions:

 Removal of excess fluids from body tissues;

 Fatty acid absorption and subsequent transport of fat to the circulatory system;

 Production of immune cells (such as lymphocytes, monocytes and antibody-producing cells known as plasmocytes).

Lymphatic vessels have the function drain excess fluid that comes out of the blood and bathes the cells. This excess fluid, which circulates in the lymphatic vessels and is returned to the blood, is called lymph.

Lymph:

It is a clear, whitish (sometimes yellowish or pink), alkaline, salty-flavored liquid that circulates through the lymphatic vessels. About 2/3 of all lymph is derived from the liver and intestine. Its composition is similar to that of blood, but has no red blood cells, although it contains white blood cells of which 99% are lymphocytes. In the blood lymphocytes represent about 50% of the total white blood cells. Lymph is transported through the lymphatic vessels unidirectionally and filtered into the lymph nodes (also known as lymph nodes or lymph nodes). After filtration, it is released into the blood, leading to the large thoracic veins.

Lymphatic circulation

The lymphatic circulation is responsible for the absorption of debris and macromolecules that cells produce during their metabolism, or that cannot be captured by the blood system.

The lymphatic system collects lymph by diffusion through the lymphatic capillaries and conducts it into the lymphatic system. Once inside the system, fluid is called lymph, and always has the same composition as interstitial fluid.

Lymphatic cells

Lymph travels through the lymphatic system due to weak muscle contractions, pulsation of nearby arteries, and movement of the extremities. All lymphatic vessels have unidirectional valves that prevent reflux, as in the venous system of the bloodstream. If a vessel becomes blocked, fluid builds up in the affected area, causing swelling called edema.

It may contain microorganisms that by passing through lymph node (lymph node) and spleen filters are eliminated. Therefore, during certain infections one may experience pain and swelling in the lymph nodes of the neck, armpit or groin, popularly known as íngua & #8221 ;.

The Human Lymphatic System

Unlike blood, which is driven through the vessels by force of the heart, the lymphatic system is not a closed system and does not have a central pump. Lymph depends exclusively on the action of external agents to be able to circulate. The lymph moves slowly and under low pressure mainly due to the compression caused by the movements of the skeletal muscles that presses the fluid through it. Rhythmic contraction of vessel walls also helps fluid through the lymphatic capillaries. This fluid is then progressively transported to larger lymphatic vessels accumulating in the right lymphatic duct (to the upper right body lymph) and the thoracic duct (to the rest of the body); These ducts flow into the circulatory system in the left and right subclavian vein.Right Lymphatic Duct

Right Lymphatic Duct

This duct runs along the medial border of the anterior scalene muscle at the base of the neck and ends at the junction of the right subclavian vein with the right internal jugular vein. Its orifice is fitted with two semilunar valves, which prevent the passage of venous blood to the duct. This duct leads the lymph to blood circulation in the following regions of the body: the right side of the head, neck and chest, the right upper limb, the right lung, the right side of the heart and the diaphragmatic face of the liver.

Thoracic Duct

It conducts lymph from most of the body to the blood. It is the trunk common to all lymphatic vessels except the vessels mentioned above (right lymphatic duct). It extends from the second lumbar vertebra to the base of the neck. It begins in the abdomen by a dilation, the kilo cistern, enters the chest through the aortic hiatus of the diaphragm and rises between the aorta and the azygos vein. It ends by flowing into the angle formed by the junction of the left subclavian vein with the left internal jugular vein.

Lymphatic Organs:

Lymphatic OrgansThe spleen, lymph nodes (lymph nodes), palatine tonsils (tonsils), pharyngeal tonsil (adenoids) and thymus (lymphocyte-rich reticular connective tissue) are organs of the lymphatic system. Some authors consider the bone marrow belonging to the lymphatic system because they produce lymphocytes. These organs contain a framework that supports the circulation of A and B lymphocytes and other immune cells such as macrophages and dendritic cells. When microorganisms invade the body or it encounters another antigen (such as pollen), the antigens are transported from the tissue to the lymph. Lymph is carried through the lymphatic vessels to the regional lymph node. At the lymph node, macrophages and dendritic cells phagocyte the antigens, process them, and present the antigens to the lymphocytes, which can then initiate antibody production or serve as memory cells to recognize the antigen again in the future.

Spleen:

The spleen is located in the left hypochondrium region, but its cranial extremity extends into the epigastric region. It is situated between the bottom of the stomach and the diaphragm. It is soft, of very friable consistency, highly vascularized and of a dark purple color. The size and weight of the spleen varies greatly, in adults it is about 12 cm long, 7 cm wide and 3 cm thick.
The spleen is a lymphoid organ although it does not filter lymph. It is an organ excluded from the lymphatic circulation but interposed in the blood circulation and whose venous drainage necessarily passes through the liver. It has a large amount of macrophages that, through phagocytosis, destroy microbes, tissue remnants, foreign substances, already worn out circulating blood cells such as erythrocytes, leukocytes and platelets. In this way, the spleen “cleanses” the blood, acting as a filter of this essential fluid. The spleen also plays a role in the immune response by reacting to infectious agents. It is even considered by some scientists, a large lymph node.

Spleen LOCATION
 Spleen LOCATION
Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.
Spleen Anatomy
 
Spleen Anatomy
Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.

Its main functions are to reserve blood in the case of heavy bleeding, destruction of red blood cells and preparation of a new hemoglobin from the iron released from the destruction of red blood cells.

Lymph Nodes (Lymph Nodes):

They are small bean-shaped organs located along the lymphatic canal. They are the most numerous lymphatic organs in the body. They store white cells (lymphocytes) that have a bactericidal effect, that is, they are cells that fight infections and diseases. When an infection occurs, they may become large and sore while reacting to invading microorganisms. They also release lymphocytes into the bloodstream. They have structure and function very similar to those of the spleen. They are distributed in ganglion chains (eg cervical, axillary, inguinal, etc.). The popular term “tongue” refers to the appearance of a painful lump.

Lymph nodes tend to cluster in groups (armpits, neck and groin). When a body part becomes infected or inflamed, the nearest lymph nodes become dilated and tender. There are about 400 ganglia in man, of which 160 are in the neck region.

 MacrLymph Nodesphage: They have phagocytosis capacity and can ingest up to 100 bacteria before they die themselves, which also make them important in eliminating necrotic tissues.

 Lymphocytes: A type of white blood cell. 99% of the white blood cells present in the lymph are lymphocytes. They produce antibodies to defend the body from infections. Like other blood cell types, lymphocytes develop in the bone marrow and move in the lymphatic system.

 T cells & #8211; They begin to live as immature cells called stem cells. Even in childhood, some lymphocytes migrate to the thymus, where they mature and become T cells. Under normal conditions, most lymphocytes circulating in the body are T cells. Their function is to recognize and destroy abnormal body cells (eg virus infected cells). T lymphocytes learn how to differentiate what is proper to the body from what is not yet in the thymus. Mature T lymphocytes leave the thymus and enter the lymphatic system, where they act as part of the immune surveillance system.

 B cells & #8211; They remain in the bone marrow and mature into B cells. B cells recognize 'foreign' cells and materials (such as bacteria that have invaded the body). When these cells come into contact with a foreign protein (eg, on the surface of bacteria), they produce antibodies that 'stick' to the surface of the foreign cell and cause its destruction. Derived from a stem cell (stem cell) of the bone marrow and mature until they turn into plasma cells, which secrete antibodies.

Both T and B lymphocytes play an important role in the recognition and destruction of infectious organisms such as bacteria and viruses. Natural killer cells, slightly larger than T and B lymphocytes, are named for killing certain microbes and cancer cells. The "natural" of their name indicates that they are ready to destroy a variety of target cells as soon as they are formed, rather than requiring the maturation and educational process that B and T lymphocytes need. Natural killer cells also produce some cytokines, messenger substances that regulate some of the functions of T lymphocytes, B lymphocytes and macrophages.


Palatine Tonsils - Pharyngeal TonsilaPalatine Tonsils (Tonsils)
:

The palatine tonsil is located on the lateral wall of the oral pharynx between the two palatine arches. Produce lymphocytes.

Pharyngeal Tonsil (Adenoids):

It is a bulge produced by lymphatic tissue found in the posterior wall of the pharyngeal nasal part. This during childhood usually hypertrophy into a considerable mass known as adenoid.

thymus:

Thymus PositionA child's thymus is a prominent organ in the anterior portion of the superior mediastinum, while the adult-old thymus can hardly be recognized due to atrophic changes. During its growth period it is very close to a gland in appearance and structure.

The thymus consists of two lateral lobes kept in close contact by connective tissue, which also forms a distinct capsule for the whole organ. It lies partially on the thorax and neck, extending from the fourth costal cartilage to the lower edge of the thyroid gland. The two wolves usually vary in size and shape, the right usually overlaps the left. It has a pinkish, soft and lobulated gray color, measuring approximately 5 cm long, 4 cm wide and 6 mm thick.

Considered a lymphatic organ because it is made up of a large number of lymphocytes and its only known function is to produce lymphocytes. The most developed lymphatic organ in the prenatal period, involves from birth to puberty.

thymus thymus
SURFACE LYMPHODS AND LYMPHATIC VESSELS OF HEAD AND NECK
 SURFACE LYMPHODS AND LYMPHATIC VESSELS OF HEAD AND NECK
Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.
PHARMACEUTICAL LYMPHATIC VESSELS AND LYMPHONES
 
PHARMACEUTICAL LYMPHATIC VESSELS AND LYMPHONES
Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.
LYMPHATIC VESSELS AND LAMPHONES OF THE MAMMARY GLAND
 LYMPHATIC VESSELS AND LAMPHONES OF THE MAMMARY GLAND
Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.
LYMPHATIC VESSELS AND LYMPHODS OF THE TOP MEMBER
 
 LYMPHATIC VESSELS AND LYMPHODS OF THE TOP MEMBER
Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.
LYMPHODS AND LYMPHATIC VASE PAINTS OF THE BACK ABDOMINAL WALL
 LYMPHODS AND LYMPHATIC VASE PAINTS OF THE BACK ABDOMINAL WALL
Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.
LYMPHATIC VESSELS AND LYMPHONODES OF THE PERINEY AND INGUINAL REGION
 
LYMPHATIC VESSELS AND LYMPHONODES OF THE PERINEY AND INGUINAL REGION
Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.
LYMPHATIC VESSELS AND LYMPHODS OF THE LOWER MEMBER
 LYMPHATIC VESSELS AND LYMPHODS OF THE LOWER MEMBER
Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.
LYMPHATIC VESSELS AND LYMPHODS OF THE POPLIT REGION
 
LYMPHATIC VESSELS AND LYMPHODS OF THE POPLIT REGION
Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.