TheLymphatic

System

** The lymphatic system is the system of vessels, cells, and organsthat carries excess fluids to the bloodstream and filters pathogens from the blood .

** is part of the circulatory system and a vital part of the immune system .

Lymphatic SystemComponents of Lymphatic System :-

A- Lymph Vessels . Lymphatic Capillaries .Lymph is the fluid .Lymphatic vessels .Lymph nodes .Lymphatic ducts .

. Lymph is formed when high arterial pressure forces fluid out of the capillaries and into the tissue.

* The human circulatory system processes an average of 20 litres of blood per day through capillary filtration, which removes plasma while leaving the blood cells. Roughly 17 litres of the filtered plasma are reabsorbed directly into the blood vessels, while the remaining three litres remain in the interstitial fluid.

Lymph Fluid

Lymph Drainage Into Veins

Lymph Vessels

* The lymph vessels transport the lymph to the lymph nodes, which are soft, ovoid organs lying along the course of lymphatic vessels.

* They range in size from 2 - 25 mm. There can be from 400 - 700 nodes scattered throughout the human body.

* Half of them are located in the abdomen; many are in the cervical (neck) region. The main groups of nodes are found in the major articulations of the body, with the exception of the wrists.

LYMPH NODES

• HELP PROTECT THE BODY BY REMOVING FOREIGN MATERIAL (BACTERIA AND TUMOR CELLS)

• PROTECT THE BODY BY PRODUCING LYMPHOCYTES .

• LARGE CLUSTERS IN INGUINAL, AXILLARY, CERVICAL REGIONS

• OUTER CORTEX CONTAIN LYMPHOCYTES, INNER MEDULLA CONTAIN PHAGOCYTIC MACROPHAGES

Lymph Node

CortexThe outer cortex consists mainly of the B cells arranged as follicles, which may develop a germinal center when challenged with an antigen, and the deeper cortex mainly consisting of the T cells .________________________________________________Medullacontains large blood vessels, sinuses and

medullary cords that contain antibody-secreting plasma cells.The medullary cords are cords of lymphatic tissue, and include plasma cells, macrophages, and B cells.

Lymph nodes filter the lymph and also contain large numbers of white blood cells (a big part of the immune system), which remove foreign cells and debris from the lymph.

When you get certain infections, the lymph nodes swell with billions of white blood cells working to clear the foreign cells that are causing the infection.

The filtered lymph then flows back into the blood stream at certain points.

• Intestinal Trunk

 

• Lumbar Trunk

 

• Bronchmediastinal Trunk

 

• Subclavian Trunk

 

• Jugular Trunks

Lymphatic Trunks

• Thoracic duct:

 

• Right lymphatic duct

Major Lymphatic ducts

The lymphatic system has a slow rhythm, low velocity and low pressure

Lymphatic tissue is made up of a framework of reticular fibers which are produced by reticular cells and which support lymphocytes, macrophages, and related cells. Lymphatic tissue may be found either as scattered foci of cells, as dense nodules within connective tissue (especially in the gut as tonsils or Peyer's Patches), or as aggregations of lymphoid cells enclosed within a capsule such as the lymph nodes, spleen and thymus. Primary : Bone Marrow – Thymus gland .Secondary : Tonsils Lymph NodesSpleen

B- Lymphatic tissue

Derivation and Distribution of Lymphocytes

Location – behind the sternum in the mediastinum

The capsule divides it into 2 lobesDevelopment

Infant – conspicuousPuberty – maximum sizeMaturity – decreases in size

FunctionDifferentiation and maturation of T cells

Thymus Gland

Thymus Gland

Largest lymphatic organLocated between the stomach & diaphragmStructure is similar to a node

Spleen

SPLEEN- FILTERS BLOOD- DESTROY WORN- OUT RBC- STORE PLATELETS AND ACT AS BLOOD

RESERVOIR- HEMATOPOEISIS IN FETUS BUT ONLY

PRODUCE LYMPHOCYTES IN ADULTS

Multiple groups of large lymphatic nodulesLocation – mucous membrane of the oral and

pharyngeal cavitiesPalatine tonsils

Posterior-lateral walls of the oropharynxPharyngeal tonsil

Posterior wall of nasopharynxLingual tonsils

Base of tongue

Tonsils

Tonsils

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Lymphocyte cells are produced in the bone marrow. There are two major classes: T cells processed in the thymus, and B cells which mature outside of the thymus. T cells act as messengers and destroyers against pathogens. B cells secrete antibodies that match a specific invading antigen. A lymphocyte is a type of white blood cell which function is to find and eliminate bacteria, viruses, and other foreign materials.

Lymphocytes

THYMUS GLAND- LYMPHATIC MASS OVERLYING THE

HEART- PRODUCES THYMOSIN HORMONE

TONSILS- RING THE PHARYNX- TRAP AND REMOVE ANY BACTERIA

ENTERING THE THROAT - ( TONSILLITIS)

PEYER’S PATCHES - PREVENT BACTERIA FROM

PENETRATING THE INTESTINAL WALL

CELLS OF THE IMMUNE SYSTEM

1. LYMPHOCYTESB LYMPHOCYTES – PRODUCE

ANTIBODIES- DEVELOP IN BM

T LYMPHOCYTES – CELL MEDIATED IMMUNITY

- DEVELOP IN THYMUS2. MACROPHAGES

ARISE FROM MONOCYTESENGULF FOREIGN PARTICLESPRESENT FRAGMENTS OF ANTIGENS ON

THEIR SURFACE

INTERACT WITH LYMPHOCTES IN IMMUNE

RESPONSE