The pathway of lymph is an open channel where the lymphatic fluid circulates. Since it is a one-way channel, lymph can move from tissue spaces to the blood. The lymph typically moves from lymphatic vessels to lymphatic trunks, collecting ducts, and ultimately into the subclavian veins. Here, let us discuss the circulation of lymph with the help of a flowchart.
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Circulation of Lymph
The lymphatic system emerges from tissue spaces as a fine meshwork of vessels. It is a complex fluid drainage system. Normal blood circulation forces fluid out of the bloodstream, where it is filtered by lymph nodes to get rid of bacteria and abnormal cells. Thereafter, the lymph vessels carry this fluid back into the bloodstream.
When the interstitial fluid reaches lymph capillaries, it is called lymph. The interstitial fluid is transferred from lymphatic capillaries to lymphatic collecting vessels, where it is filtered by lymph nodes throughout the length of the vessels and stopped from flowing backwards by valves. Lymph moves from lymphatic vessels to lymphatic trunks, collecting ducts, and ultimately into the subclavian veins.
Circulation of Lymph – Flow Chart
Afferent lymph vessel
Efferent lymph vessel
There are two large collecting ducts. One on the right side (right lymphatic duct) and the other on the left side (thoracic duct). The right lymphatic duct drains into the junction of the right subclavian veins and the right internal jugular veins. Likewise, the thoracic duct drains between the left subclavian and left internal jugular veins. More than two-thirds of the body’s tissue spaces have lymphatic vessels that drain into the thoracic duct.
Also Check:Composition and Function of Lymph in Humans
Rate of Lymph Circulation
Lymph enters the blood at a rate of about 120 mL per hour. Out of this, the right lymphatic duct receives 20 mL/hour and the thoracic duct receives roughly 100 mL/hour.
Factors Increasing Lymph Flow
- The rise in interstitial fluid pressure encourages lymphatic flow.
- The increase in the blood capillary pressure.
- Increasing lymph capillary surface area through dilatation.
- The rise in lymph capillaries’ permeability.
- The rise in tissues’ functional activities.
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