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    Related Topics

    From Lymphatic System

    Peyer’s Patches
    Lymphoid nodules in the small intestine.
    Occipital Lymph Nodes
    Drain the back of the scalp.
    Tracheobronchial Nodes
    Drain lungs and bronchi.
    Subclavian Trunk
    Drains lymph from the upper limbs.
    Thoracic Duct
    Main lymphatic duct draining most of the body.
    Red Bone Marrow
    Produces lymphocytes; site of B-cell maturation.
    Intestinal Trunk
    Drains lymph from the intestines.
    Axillary Lymph Nodes
    Drain the upper limbs and chest wall.
    Waldeyer’s Ring
    Ring of lymphoid tissue surrounding the naso- and oropharynx.
    Superficial Cervical Lymph Nodes
    Drain superficial structures of the head and neck.
    Preaortic Nodes
    Located in front of the aorta.
    Pretracheal Nodes
    Located anterior to the trachea.
    Parotid Lymph Nodes
    Drain the lateral face and scalp.
    Tubal Tonsils
    Near openings of the auditory tubes.
    Submandibular Lymph Nodes
    Drain the face, mouth, and pharynx.
    Palatine Tonsils
    Located on each side of the oropharynx.
    Lymph Nodes
    Small structures that filter lymph and store immune cells.
    Apical Axillary Nodes
    Located at the apex of the axilla.
    Spleen
    Filters blood and initiates immune response.
    Thymus
    Primary lymphoid organ for T-cell maturation.
    Deep Cervical Lymph Nodes
    Located along internal jugular vein; receive lymph from head and neck.
    Retroaortic Nodes
    Located behind the aorta.
    Submental Lymph Nodes
    Drain the floor of the mouth and central lower lip.
    Iliac Lymph Nodes
    Include external, internal, and common iliac nodes.
    Popliteal Lymph Nodes
    Drain the foot and leg.

    Lymphatic Collecting Vessels

    Reviewed by our medical team

    Carry lymph through lymph nodes.

    1. Overview

    Lymphatic collecting vessels are an integral component of the lymphatic system, responsible for transporting lymph from peripheral tissues toward larger lymphatic trunks and eventually into the venous circulation. These vessels are intermediate between the smaller lymphatic capillaries and the larger lymphatic trunks or ducts. They ensure the unidirectional flow of lymph, help filter it through lymph nodes, and play a vital role in immune surveillance, tissue fluid balance, and lipid absorption.

    2. Location

    Lymphatic collecting vessels are distributed throughout the body, paralleling veins and arteries. They are present in both superficial and deep regions:

    • Superficial collecting vessels: Located in the subcutaneous tissues, these follow the course of superficial veins and drain skin and superficial fascia.

    • Deep collecting vessels: Located in deeper tissues, often accompanying arteries, they drain muscles, joints, and internal organs.

    These vessels eventually converge at regional lymph nodes and drain into larger lymphatic trunks, such as the jugular, subclavian, bronchomediastinal, intestinal, and lumbar trunks, which in turn drain into the thoracic duct or right lymphatic duct.

    3. Structure

    Lymphatic collecting vessels are structurally similar to veins but have thinner walls and more internal valves. Key components include:

    • Endothelium: A single layer of endothelial cells lining the lumen that facilitates lymph flow.

    • Valves: Numerous bicuspid valves are present to prevent backflow and ensure unidirectional flow of lymph.

    • Tunica media: Contains smooth muscle that helps propel lymph via rhythmic contractions (lymphangion activity).

    • Tunica adventitia: Composed of connective tissue that provides support and elasticity.

    Between each pair of valves lies a segment called a lymphangion, which behaves as a functional unit capable of autonomous contraction, regulated by stretch and local signals.

    4. Function

    Lymphatic collecting vessels serve several critical functions:

    • Transport of lymph: They collect lymph from capillary beds and move it centrally through lymph nodes and into larger lymphatic trunks.

    • Immune cell trafficking: They carry antigen-presenting cells (e.g., dendritic cells) and lymphocytes toward lymph nodes for immune processing.

    • Facilitation of filtration: They direct lymph through multiple lymph nodes, where it is screened for pathogens, debris, and tumor cells.

    5. Physiological Role(s)

    Lymphatic collecting vessels are essential for maintaining tissue and immune homeostasis:

    • Fluid balance: They return interstitial fluid and plasma proteins that leak from blood capillaries back into the circulatory system.

    • Fat absorption: In the gastrointestinal tract, specialized collecting vessels called lacteals absorb dietary fats and transport them as chyle into the bloodstream.

    • Edema prevention: Efficient lymphatic drainage prevents accumulation of interstitial fluid, thus avoiding tissue swelling.

    • Immunosurveillance: Lymphatic vessels serve as conduits for immune surveillance by transporting antigens and immune cells to regional lymph nodes.

    These roles are especially important during inflammation, infection, and tissue repair, where lymph flow increases and immune coordination becomes critical.

    6. Clinical Significance

    Lymphedema

    Dysfunction or obstruction of collecting vessels can lead to lymphedema, characterized by accumulation of lymph in tissues, resulting in chronic swelling, typically of the limbs. Causes include:

    • Primary lymphedema: Congenital malformations or genetic conditions affecting lymphatic vessels.

    • Secondary lymphedema: Acquired due to surgery (e.g., lymph node dissection), radiation therapy, infection (e.g., filariasis), or trauma.

    Cancer Metastasis

    Collecting vessels are key pathways for the spread of malignancies. Tumor cells can enter lymphatic capillaries and travel through collecting vessels to regional lymph nodes. This is why lymph node assessment is crucial in staging cancers such as breast, melanoma, cervical, and gastrointestinal cancers.

    Lymphangitis

    Infection of lymphatic vessels, typically bacterial, results in a condition called lymphangitis. It presents with red streaks along the course of collecting vessels, often associated with fever and tender lymphadenopathy. It requires prompt antibiotic treatment to prevent systemic spread.

    Lymphatic Insufficiency

    In some chronic diseases, collecting vessels may become dilated, incompetent, or fibrotic, impairing lymph flow. This may contribute to chronic inflammation, delayed wound healing, or susceptibility to infections.

    Imaging and Interventions

    Modern techniques such as lymphoscintigraphy, indocyanine green (ICG) lymphography, and MR lymphangiography can visualize collecting vessels and assess lymphatic function. In some cases, lymphovenous anastomosis or vascularized lymph node transfer is performed to restore lymphatic flow.

    Did you know? The tonsils, which are part of the lymphatic system, help trap pathogens that enter through the mouth or nose.