What is the does the lymphatic system do as a whole and how is it organized in general?
It consists of a collecting network of thin-walled vessels that drain protein filled fluid from the interstitial spaces throughout the body. It does not have a pumping mechanism, and it does not have a closed circuit rather it returns the fluid back to th
Describe the structure and function of lymphatic capillaries.
The initial/terminal capillaries have a single endothelial layer with many gaps between the cells. These capillaries collect extravasated proteins mainly albumin and water from the extracellular space and take this lymph to the larger vessels of the lymph
Describe the structure and function of the larger lymphatic collecting vessels.
Collecting lymphatic vessels collect the lymph from initial capillaries and they have valves to keep flow unidirectional. The prenodal (afferent) vessels join with successively larger vessels and eventually on the way run into multiple sets of lymph nodes
Describe the function of lymph nodes.
The nodes filter the lymph. The cells in the nodes provide immune surveillance and remove debris, and therefore act as the body's safety net.
How does the lymph get into the lymphatic system?
The capillary lymphatic endothelial cells do not have tight junctions, and the gaps between the cells is increased when fluid increases in the tissue as the cells are pulled apart by anchoring filaments. Then by diffusion these fluids, proteins, and debri
Why is it important to make sure that the fluid and protein balance maintained?
In normal blood flow through arteries and veins about 10% of the fluid and proteins through the capillaries is trapped in the tissues of the body. This means that about 1 to 2 liters per day are lost and this would quickly become life threatening as the v
How does the lymphatic system help with immune defense?
The system plays an integral role as it is the first line of defense against disease progression. The lymph fluid transports the good antibodies and lymphocytes and it filters out the bad pathogens. Therefore the lymphatic system not only removes the path
What is the normal size/shape of a lymph node and what happens when there is an infection or other disease?
The lymph node is normally a firm, symmetrical kidney bean shaped structure that is normally the size of jelly beans. The lymph node can become inflammed with infection and this is called lymphadenitis. Lymph nodes can also become swollen which may be a s
What happens if the lymph node does not filter an infection?
The infection can flow through the lymph nodes into the venous system and cause septicemia has a negative systemic infection.
How does the lymph move and flow through the system?
The lymphatic capillaries do not have smooth muscles so they depend on phyiologic forces to move the lymph forward. Skeletal muscle contractions or arterial pulsations can help move the lymph and they also have a few flimsy valves that help prevent backfl
How does the lymph system operate in fat absorption and what is the first stop that it makes in the process?
The lacteals which are the highly absorptive lymphatic capillaries in the intestinal villi absorb the large molecular weight molecules such as lipids and lipophilic compounds like fat-soluble vitamins. These then converge into intestinal trunks and as the
What are the physiologic/clinical effects of the fat absorption in the lymphatic vessels?
If the lacteals do not work properly it can lead to serious malnutrition as lipids are not correctly handled. Also these can become congested in the lymphatic system after a fatty meal and they go straight into the systemic circulation from there. This is
What happens to the lymph from the chyle cistern?
The thoracic duct receives the lymph from the chyle cistern and pushes it up against gravity to the venous angle in the left root of the neck. The movement is aided by the diaphragm and the thoracic aorta because it is sandwiched between the two. The aort
What are other organs that are within the lymphoid system?
The spleen, thymus, Peyer's patches of the small intestine, the appendix, and the tonsils are considered lymphoid organs.
Describe the anatomical pathway of the superficial lymphatic drainage system?
It is a purely superficial system that drains the skin and superficial fascia from both extremeties and the trunk. Also there is a deeper superficial system that follows the deep veins in each extremity. The following of the veins is similar as this is ho
Describe the anatomical pathway of the deep lymphatic drainage system?
It drains the viscera and the flow within these lymphatic pathways drain into the chyle cistern. Then it moves onto the thoracic duct and flows passively into the venous side of the circulatory system. The lymph that enters here is from the lower extremit
In what direction does the superficial lymphatic drainage pattern?
It drains from the distal to proximal ends. It usually flow along the superficial venous system and moves upward against gravity.
What is lymphangitis?
It is defined as an inflammation along the lymphatic vessels due to distal pathogens.
What is lymphadenitis and what leads to it?
When the ascending lymphangitis starts at a distal end of the body and moves up the extremeties along the lymphatic vessels, the lymph nodes begin to contain the spread and become inflamed themselves which is lymphadenitis. This can be palpated during an
Specifically for lymphatic drainage patterns in the lower extremity what are the two important groups of lymph nodes?
There is the Vertical group of Inguinal Lymph Nodes that receives lymph from the vessels along the great saphenous vein. There is a horizontal group of Inguinal Lymph nodes and they receive lymph from the anterior abdominal wall below the umbilicus, hip,
Specifically for lymphatic drainage patterns in the anterior trunk, what is the drainage system like?
Cutaneous lymphatic capillaries drain to the nodes on the same side as they are located. The right thorax drains into the right axillary nodes. In the head and neck the cutaneous drainage is typically bilaterally symmetrical as the lymph is dumped into th
Specifically for lymphatic drainage patterns in the head and neck, what is the drainage system like?
The lymphatic capillaries drain downward. There are lymph nodes that encircle the head and are called the pericervical collar of lymph nodes, which can be felt by palpating. Eventually the lymph moves into the deep lymphatics and flows into a collecting l
Describe the general schematics of the Deep Lymphatic Drainage System.
The convergence of the superficial lymphatic drainage system eventually creates the deep lymphatic system in the central portion of the body. The right arm, right chest, right head and neck drain into the right venous angle, whereas the rest drains into t
What happens to lymph after it leaves the inguinal region?
The deep inguinal nodes flow into the external iliac chain and nodes and these flow into the common iliav nodes. These then form the lumbar trunks which is where the lymph collects in the chyle cistern. From here at the L2 level, it flows into the thoraci
What are the possible routes for primary small cell carcinoma of the lung to follow as it metastasizes?
The cancer from the upper pulmonary lobes drain into the superior tracheo-bronchial (hilar) nodes. The lower pulmonary lobes drain to the inferior tracheo-bronchial (carinal) nodes. These then go upward to the paratracheal nodes and then these go into the
What are the possible routes for breast carcinoma to follow as it metastasizes?
The breast is a modified sweat gland so it follows the cutaneous drainage path. The majority of the lymph goes into the axilla and the lymph drains towards the nipple in a subareolar lymphatic plexus. The lymph nodes are clustered around the axillary vein
Where does the lymph go from the axillary nodes?
It travels under the clavical and upward to the neck to the supraclavicular node and then it joins the venous angle.
What is the typical flow of lymph from the breast and anterior chest?
The lymphatic channels drain toward the pectoral nodes in the anterior part of the body. Deep breast tumors will drain lymph into the posterior part of the body to the subscapular nodes. The lateral nodes receive lymph from the upper extremity and drain i
What is sentinel node mapping?
It is becoming a more normal practice to stage breast cancer. If the cancer has not reached the anterior nodes then the prognosis is much better than if it has reached the central or apical group. This technique spares a woman from havign a lymph node dis
What are the three realities of the lymphatic system?
The lymph node patterns are highly variable. The textbook drawing are idealized and probably not the case in patients or our cadavers. The easiest way to see lymph nodes is by lymphoscintigraphy by using special dyes or over the course of time.
What are causes for lymphadema?
Lymphedema or the accumulation of lymphatic fluid in the interstitial tissue that causes swelling in the body can occur with scaring from surgeries or radiation therapy, inproper dissections are performed, or when the lymphatic drainage patterns are elimi